Y sbl ip20 driver 60w connection diagram. Free homemade driver for powering LEDs from an electronic converter for energy-saving lamps. RGB LED connection

A guarantee of brightness, efficiency and durability of LED sources is proper power supply, which can be provided by special electronic devices - drivers for LEDs. They convert the AC voltage in the 220V network into a DC voltage of a given value. An analysis of the main types and characteristics of devices will help you understand what function converters perform and what to look for when choosing them.

The main function of an LED driver is to provide a stabilized current passing through the LED device. The value of the current flowing through the semiconductor crystal must correspond to the nameplate parameters of the LED. This will ensure the stability of the crystal's glow and help avoid its premature degradation. In addition, at a given current, the voltage drop will correspond to the value required for the p-n junction. You can find out the appropriate supply voltage for the LED using the current-voltage characteristic.

When lighting residential and office premises with LED lamps and luminaires, drivers are used, the power of which is supplied from a 220V alternating current network. Automotive lighting (headlights, DRLs, etc.), bicycle headlights, and portable flashlights use DC power supplies in the range from 9 to 36V. Some low-power LEDs can be connected without a driver, but then a resistor must be included in the circuit for connecting the LED to a 220-volt network.

The driver output voltage is indicated in the range of two final values, between which stable operation is ensured. There are adapters with an interval from 3V to several tens. To power a circuit of 3 series-connected white LEDs, each of which has a power of 1 W, you will need a driver with output values U - 9-12V, I - 350 mA. The voltage drop for each crystal will be about 3.3V, for a total of 9.9V, which will be within the driver range.

Main characteristics of converters

Before you buy a driver for LEDs, you should familiarize yourself with the basic characteristics of the devices. These include output voltage, rated current and power. The output voltage of the converter depends on the voltage drop across the LED source, as well as on the connection method and the number of LEDs in the circuit. The current depends on the power and brightness of the emitting diodes. The driver must provide the LEDs with the current they need to maintain the required brightness.

One of the important characteristics of the driver is the power that the device produces in the form of a load. The choice of driver power is influenced by the power of each LED device, the total number and color of the LEDs. The algorithm for calculating power is that the maximum power of the device should not be lower than the consumption of all LEDs:

P = P(led) × n,

where P(led) is the power of a single LED source, and n is the number of LEDs.

In addition, a mandatory condition must be met to ensure a power reserve of 25-30%. Therefore, the maximum power value must be no less than the value (1.3 x P).

You should also take into account the color characteristics of the LEDs. After all, semiconductor crystals of different colors have different voltage drops when a current of the same strength passes through them. So the voltage drop of a red LED at a current of 350 mA is 1.9-2.4 V, then the average value of its power will be 0.75 W. For the green analogue, the voltage drop is in the range from 3.3 to 3.9V and at the same current the power will be 1.25 W. This means that 16 red LED sources or 9 green ones can be connected to the driver for 12V LEDs.

Helpful advice! When choosing a driver for LEDs, experts advise not to neglect the maximum power value of the device.

What are the types of drivers for LEDs by device type?

Drivers for LEDs are classified by device type into linear and pulsed. The structure and typical driver circuit for linear-type LEDs is a current generator on a transistor with a p-channel. Such devices provide smooth current stabilization under the condition of unstable voltage on the input channel. They are simple and cheap devices, but they are low efficient, generate a lot of heat during operation and cannot be used as drivers for high-power LEDs.

Pulse devices create a series of high-frequency pulses in the output channel. Their operation is based on the PWM (pulse width modulation) principle, when the average output current is determined by the duty cycle, i.e. the ratio of the pulse duration to the number of its repetitions. The change in the average output current occurs due to the fact that the pulse frequency remains unchanged, and the duty cycle varies from 10-80%.

Due to the high conversion efficiency (up to 95%) and compactness of the devices, they are widely used for portable LED designs. In addition, the efficiency of the devices has a positive effect on the duration of operation of autonomous power devices. Pulse-type converters are compact in size and have a wide range of input voltages. The disadvantage of these devices is the high level of electromagnetic interference.

Helpful advice! You should purchase an LED driver at the stage of selecting LED sources, having previously decided on a circuit of LEDs from 220 volts.

Before choosing a driver for LEDs, you need to know the conditions of its operation and the location of the LED devices. Pulse-width drivers, which are based on a single microcircuit, are miniature in size and are designed to be powered from autonomous low-voltage sources. The main application of these devices is car tuning and LED lighting. However, due to the use of a simplified electronic circuit, the quality of such converters is somewhat lower.

Dimmable LED Drivers

Modern drivers for LEDs are compatible with dimming devices for semiconductor devices. The use of dimmable drivers allows you to control the level of illumination in the premises: reduce the intensity of the glow in the daytime, emphasize or hide individual elements in the interior, and zone the space. This, in turn, makes it possible not only to rationally use electricity, but also to save the resource of the LED light source.

Dimmable drivers come in two types. Some are connected between the power supply and LED sources. Such devices control the energy supplied from the power supply to the LEDs. Such devices are based on PWM control, in which energy is supplied to the load in the form of pulses. The duration of the pulses determines the amount of energy from the minimum to the maximum value. Drivers of this type are mainly used for LED modules with a fixed voltage, such as LED strips, tickers, etc.

The driver is controlled using PWM or

Dimmable converters of the second type control directly the power source. The principle of their operation is both PWM regulation and control of the amount of current flowing through the LEDs. Dimmable drivers of this type are used for LED devices with stabilized current. It is worth noting that when controlling LEDs using PWM control, effects that negatively affect vision are observed.

Comparing these two control methods, it is worth noting that when regulating the current through LED sources, not only a change in the brightness of the glow is observed, but also a change in the color of the glow. Thus, white LEDs emit yellowish light at lower currents, and glow blue when increased. When controlling LEDs using PWM control, effects that negatively affect vision and a high level of electromagnetic interference are observed. In this regard, PWM control is used quite rarely, unlike current regulation.

LED Driver Circuits

Many manufacturers produce driver chips for LEDs that allow the sources to be powered from a reduced voltage. All existing drivers are divided into simple ones, made on the basis of 1-3 transistors, and more complex ones using special microcircuits with pulse width modulation.

ON Semiconductor offers a wide selection of ICs as the basis for drivers. They are distinguished by reasonable cost, excellent conversion efficiency, cost-effectiveness and low level of electromagnetic pulses. The manufacturer presents a pulse-type driver UC3845 with an output current of up to 1A. On such a chip you can implement a driver circuit for a 10W LED.

Electronic components HV9910 (Supertex) is a popular driver chip due to its simple circuit resolution and low price. It has a built-in voltage regulator and outputs for brightness control, as well as an output for programming the switching frequency. The output current value is up to 0.01A. On this chip it is possible to implement a simple driver for LEDs.

Based on the UCC28810 chip (made by Texas Instruments), you can create a driver circuit for high-power LEDs. In such an LED driver circuit, an output voltage of 70-85V can be created for LED modules consisting of 28 LED sources with a current of 3 A.

Helpful advice! If you are planning to buy ultra-bright 10 W LEDs, you can use a switching driver based on the UCC28810 chip for designs made from them.

Clare offers a simple pulse-type driver based on the CPC 9909 chip. It includes a converter controller housed in a compact housing. Due to the built-in voltage stabilizer, the converter can be powered from a voltage of 8-550V. The CPC 9909 chip allows the driver to operate under conditions of a wide range of temperature conditions from -50 to 80°C.

How to choose a driver for LEDs

There is a wide range of LED drivers on the market from different manufacturers. Many of them, especially those made in China, are low in price. However, buying such devices is not always profitable, since most of them do not meet the declared characteristics. In addition, such drivers are not accompanied by a warranty, and if they are found to be defective, they cannot be returned or replaced with quality ones.

Thus, there is a possibility of purchasing a driver whose declared power is 50 W. However, in reality it turns out that this characteristic is not permanent and such power is only short-term. In reality, such a device will work as a 30W or maximum 40W LED driver. It may also turn out that the filling will be missing some components responsible for the stable functioning of the driver. In addition, components of low quality and with a short service life may be used, which is essentially a defect.

When purchasing, you should pay attention to the product brand. A quality product will definitely indicate the manufacturer, who will provide a guarantee and will be ready to be responsible for their products. It should be noted that the service life of drivers from trusted manufacturers will be much longer. Below is the approximate operating time of the drivers depending on the manufacturer:

driver from dubious manufacturers - no more than 20 thousand hours;
devices of average quality - about 50 thousand hours;
converter from a trusted manufacturer using high-quality components - over 70 thousand hours.

Helpful advice! The quality of the LED driver is up to you to decide. However, it should be noted that it is especially important to purchase a branded converter if we are talking about using it for LED spotlights and powerful lamps.

Calculation of drivers for LEDs

To determine the output voltage of the LED driver, it is necessary to calculate the ratio of power (W) to current (A). For example, a driver has the following characteristics: power 3 W and current 0.3 A. The calculated ratio is 10V. Thus, this will be the maximum output voltage of this converter.

Related article:

Types. Connection diagrams for LED sources. Resistance calculation for LEDs. Checking the LED with a multimeter. DIY LED designs.

If you need to connect 3 LED sources, the current of each of them is 0.3 mA at a supply voltage of 3V. Connecting one of the devices to the LED driver, the output voltage will be equal to 3V and the current will be 0.3 A. By collecting two LED sources in series, the output voltage will be equal to 6V and the current will be 0.3 A. By adding a third LED to the serial chain, we will get 9V and 0.3 A. With a parallel connection, 0.3 A will be equally distributed between the 0.1 A LEDs. Connecting the LEDs to a 0.3 A device with a current value of 0.7, they will receive only 0.3 A.

This is the algorithm for the functioning of LED drivers. They produce the amount of current for which they are designed. The method of connecting LED devices in this case does not matter. There are driver models that require any number of LEDs connected to them. But then there is a limitation on the power of LED sources: it should not exceed the power of the driver itself. Drivers are available that are designed for a certain number of connected LEDs. A smaller number of LEDs can be connected to them. But such drivers have low efficiency, unlike devices designed for a specific number of LED devices.

It should be noted that drivers designed for a fixed number of emitting diodes are provided with protection against emergency situations. Such converters do not work correctly if fewer LEDs are connected to them: they will flicker or not light up at all. Thus, if you connect voltage to the driver without an appropriate load, it will work unstable.

Where to buy drivers for LEDs

You can buy LED-drivers at specialized points selling radio components. In addition, it is much more convenient to familiarize yourself with the products and order the necessary product using the catalogs of the relevant sites. In addition, in online stores you can purchase not only converters, but also LED lighting devices and related products: control devices, connection tools, electronic components for repairing and assembling a driver for LEDs with your own hands.

Selling companies offer a huge range of drivers for LEDs, the technical characteristics and prices of which can be seen in the price lists. As a rule, product prices are indicative and are specified when ordering from the project manager. The range includes converters of various powers and degrees of protection, used for external and internal lighting, as well as for illumination and tuning of cars.

When choosing a driver, you should take into account the conditions of its use and the power consumption of the LED design. Therefore, it is necessary to purchase a driver before purchasing LEDs. So, before you buy a driver for 12 volt LEDs, you need to take into account that it should have a power reserve of about 25-30%. This is necessary in order to reduce the risk of damage or complete failure of the device due to a short circuit or voltage surges in the network. The cost of the converter depends on the number of devices purchased, form of payment and delivery time.

The table shows the main parameters and dimensions of 12 volt voltage stabilizers for LEDs, indicating their estimated price:

Modification LD DC/AC 12 V	Dimensions, mm (h/w/d)	Output current, A	Power, W	price, rub.
1x1W 3-4VDC 0.3A MR11	8/25/12	0,3	1x1	73
3x1W 9-12VDC 0.3A MR11	8/25/12	0,3	3x1	114
3x1W 9-12VDC 0.3A MR16	12/28/18	0,3	3x1	35
5-7x1W 15-24VDC 0.3A	12/14/14	0,3	5-7x1	80
10W 21-40V 0.3A AR111	21/30	0,3	10	338
12W 21-40V 0.3A AR11	18/30/22	0,3	12	321
3x2W 9-12VDC 0.4A MR16	12/28/18	0,4	3x2	18
3x2W 9-12VDC 0.45A	12/14/14	0,45	3x2	54

Making drivers for LEDs with your own hands

Using ready-made microcircuits, radio amateurs can independently assemble drivers for LEDs of various powers. To do this, you must be able to read electrical diagrams and have skills in working with a soldering iron. For example, you can consider several options for DIY LED drivers for LEDs.

The driver circuit for a 3W LED can be implemented based on the PT4115 chip made in China by PowTech. The microcircuit can be used to power LED devices over 1W and includes control units that have a fairly powerful transistor at the output. The PT4115 based driver is highly efficient and has a minimum number of wiring components.

Overview of PT4115 and technical parameters of its components:

light brightness control function (dimming);
input voltage – 6-30V;
output current value – 1.2 A;
current stabilization deviation up to 5%;
protection against load breaks;
presence of outputs for dimming;
efficiency – up to 97%.

The microcircuit has the following conclusions:

for output switch – SW;
for the signal and supply sections of the circuit – GND;
for brightness control – DIM;
input current sensor – CSN;
supply voltage – VIN;

DIY LED driver circuit based on PT4115

Driver circuits for powering LED devices with a dissipating power of 3 W can be designed in two versions. The first assumes the presence of a power source with a voltage from 6 to 30V. Another circuit provides power from an AC source with a voltage of 12 to 18V. In this case, a diode bridge is introduced into the circuit, at the output of which a capacitor is installed. It helps smooth out voltage fluctuations; its capacity is 1000 μF.

For the first and second circuits, the capacitor (CIN) is of particular importance: this component is designed to reduce ripple and compensate for the energy accumulated by the inductor when the MOP transistor is turned off. In the absence of a capacitor, all the inductive energy through the semiconductor diode DSB (D) will reach the supply voltage output (VIN) and will cause breakdown of the microcircuit relative to the supply.

Helpful advice! It should be taken into account that connecting a driver for LEDs in the absence of an input capacitor is not permitted.

Taking into account the number and how much LEDs consume, the inductance (L) is calculated. In the LED driver circuit, you should select an inductance whose value is 68-220 μH. This is evidenced by data from technical documentation. A slight increase in the value of L can be allowed, but it should be taken into account that then the efficiency of the circuit as a whole will decrease.

As soon as voltage is applied, the magnitude of the current passing through the resistor RS (works as a current sensor) and L will be zero. Next, the CS comparator analyzes the potential levels located before and after the resistor - as a result, a high concentration appears at the output. The current going to the load increases to a certain value controlled by RS. The current increases depending on the inductance value and the voltage value.

Assembling Driver Components

The wiring components of the RT 4115 microcircuit are selected taking into account the manufacturer’s instructions. For CIN, a low impedance capacitor (low ESR capacitor) should be used, since the use of other analogues will negatively affect the driver efficiency. If the device is powered from a unit with a stabilized current, one capacitor with a capacity of 4.7 μF or more will be needed at the input. It is recommended to place it next to the microcircuit. If the current is alternating, you will need to introduce a solid tantalum capacitor with a capacitance of at least 100 μF.

In the connection circuit for 3 W LEDs, it is necessary to install a 68 μH inductor. It should be located as close to the SW terminal as possible. You can make the coil yourself. To do this, you will need a ring from a failed computer and a winding wire (PEL-0.35). As diode D, you can use the FR 103 diode. Its parameters: capacitance 15 pF, recovery time 150 ns, temperature from -65 to 150 ° C. It can handle current pulses up to 30A.

The minimum value of the RS resistor in an LED driver circuit is 0.082 ohms, the current is 1.2 A. To calculate the resistor, you need to use the value of the current required by the LED. Below is the formula for calculation:

RS = 0.1/I,

where I is the rated current of the LED source.

The RS value in the LED driver circuit is 0.13 Ohm, respectively, the current value is 780 mA. If such a resistor cannot be found, several low-resistance components can be used, using the resistance formula for parallel and series connection in the calculation.

DIY driver layout for a 10 Watt LED

You can assemble a driver for a powerful LED yourself, using electronic boards from failed fluorescent lamps. Most often, the lamps in such lamps burn out. The electronic board remains operational, which allows its components to be used for homemade power supplies, drivers and other devices. Transistors, capacitors, diodes, and inductors (chokes) may be needed for operation.

The faulty lamp must be carefully disassembled using a screwdriver. To make a driver for a 10 W LED, you should use a fluorescent lamp with a power of 20 W. This is necessary so that the throttle can withstand the load with a reserve. For a more powerful lamp, you should either select the appropriate board, or replace the inductor itself with an analogue with a larger core. For LED sources with lower power, you can adjust the number of turns of the winding.

Next, you need to make 20 turns of wire over the primary turns of the winding and use a soldering iron to connect this winding to the rectifier diode bridge. After this, apply voltage from the 220V network and measure the output voltage on the rectifier. Its value was 9.7V. The LED source consumes 0.83 A through the ammeter. The rating of this LED is 900 mA, however, the reduced current consumption will increase its resource. The diode bridge is assembled by hanging installation.

The new board and diode bridge can be placed in a stand from an old table lamp. Thus, the LED driver can be assembled independently from available radio components from failed devices.

Due to the fact that LEDs are quite demanding on power supplies, it is necessary to select the right driver for them. If the converter is chosen correctly, you can be sure that the parameters of LED sources will not deteriorate and the LEDs will last their intended life.

The advantages of LED paws have been discussed many times. The abundance of positive reviews from users of LED lighting willy-nilly makes you think about Ilyich’s own light bulbs. Everything would be nice, but when it comes to calculating the conversion of an apartment to LED lighting, the numbers are a little “straining”.

To replace an ordinary 75W lamp, you need a 15W LED bulb, and a dozen such lamps need to be replaced. With an average cost of about $10 per lamp, the budget comes out to be decent, and the risk of purchasing a Chinese “clone” with a life cycle of 2-3 years cannot be ruled out. In light of this, many are considering the possibility of making these devices themselves.

Power theory for LED lamps from 220V

The most budget option can be assembled with your own hands from these LEDs. A dozen of these little ones cost less than a dollar, and the brightness corresponds to a 75W incandescent lamp. Putting everything together is not a problem, but if you don’t connect them directly to the network, they will burn out. The heart of any LED lamp is the power driver. It determines how long and how well the light bulb will shine.

To assemble a 220-volt LED lamp with your own hands, let’s look at the power driver circuit.

The network parameters significantly exceed the needs of the LED. In order for the LED to operate from the network, it is necessary to reduce the voltage amplitude, current strength and convert the alternating voltage of the network into direct voltage.

For these purposes, a voltage divider with a resistor or capacitive load and stabilizers are used.

Components of a LED luminaire

A 220-volt LED lamp circuit will require a minimum number of available components.

LEDs 3.3V 1W – 12 pcs.;
ceramic capacitor 0.27 µF 400-500V – 1 pc.;
resistor 500 kOhm - 1 Mohm 0.5 - 1 W - 1 pcs.t;
100V diode – 4 pcs.;
electrolytic capacitors 330 μF and 100 μF 16V 1 pc.;
12V voltage stabilizer L7812 or similar – 1 pc.

Making a 220V LED driver with your own hands

The 220 volt ice driver circuit is nothing more than a switching power supply.

As a homemade LED driver from a 220V network, we will consider the simplest switching power supply without galvanic isolation. The main advantage of such schemes is simplicity and reliability. But be careful when assembling, since this circuit has no current limit. The LEDs will draw their required one and a half amperes, but if you touch the bare wires with your hand, the current will reach tens of amperes, and such a shock of current is very noticeable.

The simplest driver circuit for 220V LEDs consists of three main stages:

Capacitive voltage divider;
diode bridge;
voltage stabilization cascade.

First cascade– capacitive reactance on capacitor C1 with resistor. The resistor is necessary for self-discharge of the capacitor and does not affect the operation of the circuit itself. Its rating is not particularly critical and can be from 100 kOhm to 1 Mohm with a power of 0.5-1 W. The capacitor is necessarily non-electrolytic at 400-500V (effective peak voltage of the network).

When a half-wave of voltage passes through a capacitor, it passes current until the plates are charged. The smaller its capacity, the faster the full charge occurs. With a capacity of 0.3-0.4 μF, the charging time is 1/10 of the half-wave period of the mains voltage. In simple terms, only a tenth of the incoming voltage will pass through the capacitor.

Second cascade- diode bridge. It converts alternating voltage to direct voltage. After cutting off most of the half-wave voltage with a capacitor, we get about 20-24V DC at the output of the diode bridge.

Third cascade– smoothing stabilizing filter.

A capacitor with a diode bridge acts as a voltage divider. When the voltage in the network changes, the amplitude at the output of the diode bridge will also change.

To smooth out the voltage ripple, we connect an electrolytic capacitor in parallel to the circuit. Its capacity depends on the power of our load.

In the driver circuit, the supply voltage for the LEDs should not exceed 12V. The common element L7812 can be used as a stabilizer.

The assembled circuit of a 220-volt LED lamp begins to work immediately, but before connecting it to the network, carefully insulate all exposed wires and soldering points of circuit elements.

Driver option without current stabilizer

There are a huge number of driver circuits on the network for LEDs from a 220V network that do not have current stabilizers.

The problem with any transformerless driver is the ripple of the output voltage, and therefore the brightness of the LEDs. A capacitor installed after the diode bridge partially copes with this problem, but does not completely solve it.

There will be ripple on the diodes with an amplitude of 2-3V. When we install a 12V stabilizer in the circuit, even taking into account ripple, the amplitude of the incoming voltage will be higher than the cutoff range.

Voltage diagram in a circuit without a stabilizer

Diagram in a circuit with a stabilizer

Therefore, a driver for diode lamps, even one assembled with one’s own hands, will not be inferior in pulsation level to similar units of expensive factory-made lamps.

As you can see, assembling the driver with your own hands is not particularly difficult. By changing the parameters of the circuit elements, we can vary the output signal values within wide limits.

If you want to build a 220-volt LED floodlight circuit based on such a circuit, it is better to convert the output stage to 24V with an appropriate stabilizer, since the output current of the L7812 is 1.2A, this limits the load power to 10W. For more powerful lighting sources, it is necessary to either increase the number of output stages, or use a more powerful stabilizer with an output current of up to 5A and install it on a radiator.

Homemade driver for LEDs from a 220V network. Ice driver circuits

DIY LED driver: simple circuits with descriptions

Using LEDs as lighting sources usually requires a specialized driver. But it happens that the necessary driver is not at hand, but you need to organize lighting, for example, in a car, or test the LED for brightness. In this case, you can make a driver for the LEDs yourself.

How to make a driver for LEDs

The circuits below use the most common elements that can be purchased at any radio store. No special equipment is required during assembly - all necessary tools are widely available. Despite this, with a careful approach, the devices work for quite a long time and are not much inferior to commercial samples.

Required materials and tools

In order to assemble a homemade driver, you will need:

Soldering iron with a power of 25-40 W. You can use more power, but this increases the risk of overheating of the elements and their failure. It is best to use a soldering iron with a ceramic heater and a non-burning tip, because... a regular copper tip oxidizes quite quickly and has to be cleaned.
Flux for soldering (rosin, glycerin, FKET, etc.). It is advisable to use a neutral flux - unlike active fluxes (phosphoric and hydrochloric acids, zinc chloride, etc.), it does not oxidize the contacts over time and is less toxic. Regardless of the flux used, after assembling the device, it is better to wash it with alcohol. For active fluxes this procedure is mandatory, for neutral ones - to a lesser extent.
Solder. The most common is low-melting tin-lead solder POS-61. Lead-free solders are less harmful when inhaling fumes during soldering, but have a higher melting point with lower fluidity and a tendency to degrade the weld over time.
Small pliers for bending leads.
Wire cutters or side cutters for cutting long ends of leads and wires.
Installation wires are insulated. Stranded copper wires with a cross-section of 0.35 to 1 mm2 are best suited.
Multimeter for monitoring voltage at nodal points.
Electrical tape or heat shrink tubing.
A small prototype board made of fiberglass. A board measuring 60x40 mm will be sufficient.

PCB development board for quick installation

Simple driver circuit for 1 W LED

One of the simplest circuits for powering a powerful LED is shown in the figure below:

As you can see, in addition to the LED, it includes only 4 elements: 2 transistors and 2 resistors.

The powerful n-channel field-effect transistor VT2 acts here as a regulator of the current passing through the LED. Resistor R2 determines the maximum current passing through the LED and also acts as a current sensor for transistor VT1 in the feedback circuit.

The more current passes through VT2, the greater the voltage drops across R2, accordingly VT1 opens and lowers the voltage at the gate of VT2, thereby reducing the LED current. In this way, stabilization of the output current is achieved.

The circuit is powered from a constant voltage source of 9 - 12 V, a current of at least 500 mA. The input voltage should be at least 1-2 V greater than the voltage drop across the LED.

Resistor R2 should dissipate 1-2 W of power, depending on the required current and supply voltage. Transistor VT2 is n-channel, designed for a current of at least 500 mA: IRF530, IRFZ48, IRFZ44N. VT1 – any low-power bipolar npn: 2N3904, 2N5088, 2N2222, BC547, etc. R1 – power 0.125 - 0.25 W with a resistance of 100 kOhm.

Due to the small number of elements, assembly can be carried out by hanging installation:

Another simple driver circuit based on the LM317 linear controlled voltage regulator:

Here the input voltage can be up to 35 V. The resistor resistance can be calculated using the formula:

where I is the current strength in amperes.

In this circuit, the LM317 will dissipate significant power given the large difference between the supply voltage and the LED drop. Therefore, it will have to be placed on a small radiator. The resistor must also be rated for at least 2 W.

This scheme is discussed more clearly in the following video:

Here we show how to connect a powerful LED using batteries with a voltage of about 8 V. When the voltage drop across the LED is about 6 V, the difference is small, and the chip does not heat up much, so you can do without a heatsink.

Please note that if there is a large difference between the supply voltage and the drop across the LED, it is necessary to place the microcircuit on a heat sink.

Power driver circuit with PWM input

Below is a circuit for powering high-power LEDs:

The driver is built on a dual comparator LM393. The circuit itself is a buck-converter, that is, a pulse step-down voltage converter.

Driver Features

Supply voltage: 5 - 24 V, constant;
Output current: up to 1 A, adjustable;
Output power: up to 18 W;
Output short circuit protection;
The ability to control brightness using an external PWM signal (it will be interesting to read how to adjust the brightness of an LED strip using a dimmer).

Operating principle

Resistor R1 with diode D1 form a source of reference voltage of about 0.7 V, which is additionally regulated by variable resistor VR1. Resistors R10 and R11 serve as current sensors for the comparator. As soon as the voltage across them exceeds the reference one, the comparator will close, thus closing the pair of transistors Q1 and Q2, and they, in turn, will close the transistor Q3. However, inductor L1 at this moment tends to resume the flow of current, so the current will flow until the voltage at R10 and R11 becomes less than the reference voltage, and the comparator opens transistor Q3 again.

The pair of Q1 and Q2 acts as a buffer between the output of the comparator and the gate of Q3. This protects the circuit from false positives due to interference on the Q3 gate, and stabilizes its operation.

The second part of the comparator (IC1 2/2) is used for additional brightness control using PWM. To do this, the control signal is applied to the PWM input: when TTL logic levels (+5 and 0 V) are applied, the circuit will open and close Q3. The maximum signal frequency at the PWM input is about 2 KHz. This input can also be used to turn the device on and off using the remote control.

D3 is a Schottky diode, rated for current up to 1 A. If you cannot find a Schottky diode, you can use a pulse diode, for example FR107, but the output power will then decrease slightly.

The maximum output current is adjusted by selecting R2 and turning on or off R11. This way you can get the following values:

350 mA (1 W LED): R2=10K, R11 disabled,
700 mA (3 W): R2=10K, R11 connected, nominal 1 Ohm,
1A (5W): R2=2.7K, R11 connected, nominal 1 Ohm.

Within narrower limits, adjustment is made using a variable resistor and a PWM signal.

Assembling and configuring the driver

The driver components are mounted on a breadboard. First, the LM393 chip is installed, then the smallest components: capacitors, resistors, diodes. Then transistors are installed, and lastly a variable resistor.

It is better to place elements on the board in such a way as to minimize the distance between the connected pins and use as few wires as jumpers as possible.

When connecting, it is important to observe the polarity of the diodes and the pinout of the transistors, which can be found in the technical description for these components. You can also check diodes using a multimeter in resistance measurement mode: in the forward direction, the device will show a value of about 500-600 Ohms.

To power the circuit, you can use an external DC voltage source of 5-24 V or batteries. 6F22 (“crown”) and other batteries have too small a capacity, so their use is impractical when using high-power LEDs.

After assembly, you need to adjust the output current. To do this, LEDs are soldered to the output, and the VR1 engine is set to the lowest position according to the diagram (checked with a multimeter in the “testing” mode). Next, we apply the supply voltage to the input, and by rotating the VR1 knob we achieve the required brightness.

List of elements:

Conclusion

The first two of the considered circuits are very simple to manufacture, but they do not provide short circuit protection and have rather low efficiency. For long-term use, the third circuit on LM393 is recommended, since it does not have these disadvantages and has greater capabilities for adjusting the output power.

ledno.ru

220V LED driver circuit

Power theory for LED lamps from 220V

To assemble a 220-volt LED lamp with your own hands, let’s look at the power driver circuit.

For these purposes, a voltage divider with a resistor or capacitive load and stabilizers are used.

Components of a LED luminaire

A 220-volt LED lamp circuit will require a minimum number of available components.

LEDs 3.3V 1W – 12 pcs.;
ceramic capacitor 0.27 µF 400-500V – 1 pc.;
resistor 500kOhm - 1Mohm 0.5 - 1W - 1 pcs.t;
100V diode – 4 pcs.;
electrolytic capacitors 330 μF and 100 μF 16V 1 pc.;
12V voltage stabilizer L7812 or similar – 1 pc.

Making a 220V LED driver with your own hands

The 220 volt ice driver circuit is nothing more than a switching power supply.

The simplest driver circuit for 220V LEDs consists of three main stages:

Capacitive voltage divider;
diode bridge;
voltage stabilization cascade.

The first stage is capacitance on capacitor C1 with a resistor. The resistor is necessary for self-discharge of the capacitor and does not affect the operation of the circuit itself. Its rating is not particularly critical and can be from 100 kOhm to 1 Mohm with a power of 0.5-1 W. The capacitor is necessarily non-electrolytic at 400-500V (effective peak voltage of the network).

The second stage is a diode bridge. It converts alternating voltage to direct voltage. After cutting off most of the half-wave voltage with a capacitor, we get about 20-24V DC at the output of the diode bridge.

The third stage is a smoothing stabilizing filter.

A capacitor with a diode bridge acts as a voltage divider. When the voltage in the network changes, the amplitude at the output of the diode bridge will also change.

To smooth out the voltage ripple, we connect an electrolytic capacitor in parallel to the circuit. Its capacity depends on the power of our load.

In the driver circuit, the supply voltage for the LEDs should not exceed 12V. The common element L7812 can be used as a stabilizer.

The assembled circuit of a 220-volt LED lamp begins to work immediately, but before connecting it to the network, carefully insulate all exposed wires and soldering points of circuit elements.

Driver option without current stabilizer

There are a huge number of driver circuits on the network for LEDs from a 220V network that do not have current stabilizers.

Voltage diagram in a circuit without a stabilizer

Diagram in a circuit with a stabilizer

Therefore, a driver for diode lamps, even one assembled with one’s own hands, will not be inferior in pulsation level to similar units of expensive factory-made lamps.

As you can see, assembling the driver with your own hands is not particularly difficult. By changing the parameters of the circuit elements, we can vary the output signal values within wide limits.

svetodiodinfo.ru

How to choose an LED driver, led driver

The most optimal way to connect to 220V, 12V is to use a current stabilizer or LED driver. In the language of the intended enemy it is written “led driver”. By adding the desired power to this request, you can easily find a suitable product on Aliexpress or Ebay.

1. Features of Chinese
2. Service life
3. LED driver 220V
4. RGB driver 220V
5. Module for assembly
6. Driver for LED lamps
7. Power supply for LED strip
8. DIY LED driver
9. Low voltage
10. Brightness adjustment

Features of Chinese

Many people like to buy from the largest Chinese bazaar, Aliexpress. prices and assortment are good. LED driver is most often chosen due to its low cost and good performance.

But with the rise in the dollar exchange rate, it became unprofitable to buy from the Chinese, the cost became equal to the Russian one, and there was no guarantee or possibility of exchange. For cheap electronics, the characteristics are always overestimated. For example, if the power specified is 50 watts, at best this is the maximum short-term power, not constant. The nominal will be 35W - 40W.

In addition, they save a lot on the filling to reduce the price. In some places there are not enough elements that ensure stable operation. The cheapest components are used, with a short service life and low quality, so the defect rate is relatively high. As a rule, components operate at the limit of their parameters, without any reserve.

If the manufacturer is not listed, then he does not have to be responsible for the quality and no review will be written about his product. And the same product is produced by several factories in different configurations. For good products, the brand must be indicated, which means that he is not afraid to be responsible for the quality of his products.

One of the best is the MeanWell brand, which values the quality of its products and does not produce junk.

Life time

Like any electronic device, the LED driver has a service life that depends on operating conditions. Branded modern LEDs already work up to 50-100 thousand hours, so the power fails earlier.

Classification:

consumer goods up to 20,000 hours;
average quality up to 50,000 hours;
up to 70,000h. power supply using high-quality Japanese components.

This indicator is important when calculating long-term payback. There is enough consumer goods for household use. Although the miser pays twice, and this works great in LED spotlights and lamps.

LED driver 220V

Modern LED drivers are designed using a PWM controller, which can stabilize the current very well.

Main parameters:

rated power;
operating current;
number of connected LEDs;
Power factor;
Stabilizer efficiency.

Housings for outdoor use are made of metal or impact-resistant plastic. When the case is made of aluminum, it can act as a cooling system for electronic components. This is especially true when filling the body with compound.

The markings often indicate how many LEDs can be connected and what power. This value can be not only fixed, but also in the form of a range. For example, it is possible to connect 12 220 LEDs from 4 to 7 pieces of 1W each. It depends on the LED driver circuit design.

RGB driver 220V

Three-color RGB LEDs differ from single-color LEDs in that they contain crystals of different colors (red, blue, and green) in one housing. To control them, each color must be lit separately. For diode strips, an RGB controller and power supply are used for this.

If a power of 50W is indicated for an RGB LED, then this is the total for all 3 colors. To find out the approximate load on each channel, divide 50W by 3, we get about 17W.

In addition to powerful led drivers, there are also 1W, 3W, 5W, 10W.

There are 2 types of remote controls. With infrared control, like a TV. With radio control, the remote control does not need to be pointed at the signal receiver.

Assembly module

If you are interested in an LED driver for assembling an LED spotlight or lamp with your own hands, then you can use an LED driver without a housing.

If you already have a current stabilizer for LEDs that is not suitable for the current strength, then you can increase or decrease it. Find the PWM controller chip on the board, on which the characteristics of the LED driver depend. There is a marking on it, by which you need to find the specifications for it. The documentation will indicate a typical connection diagram. Typically, the output current is set by one or more resistors connected to the pins of the microcircuit. If you change the value of the resistors or install a variable resistance according to the information from the specifications, you can change the current. Just do not exceed the initial power, otherwise it may fail.

Driver for LED lamps

There are slightly different requirements for the power supply of street lighting equipment. When designing street lighting, it is taken into account that the LED driver will work in conditions from -40° to +40° in dry and humid air.

The ripple factor for luminaires may be higher than for indoor use. For street lighting, this indicator becomes unimportant.

When operating outdoors, the power supply must be completely sealed. There are several ways to protect against moisture:

filling the entire board with sealant or compound;
assembly of the block using silicone seals;
placement of the LED driver board in the same volume as the LEDs.

The maximum level of protection is IP68, designated as “Waterproof LED Driver” or “waterproof electronic led driver”. For the Chinese, this is not a guarantee of waterproofness.

In my experience, the stated level of protection against moisture and dust does not always correspond to the real one. In some places there may not be enough seals. Pay attention to the cable entry and exit from the housing; there are samples with a hole that is not closed with sealant or other means. Water through the cable will be able to flow into the housing and then evaporate within it. This will cause corrosion on the board and exposed wires. This will greatly reduce the life of the spotlight or lamp.

Power supply for LED strip

LED strip works on a different principle; it requires a stabilized voltage. The current-setting resistor is installed on the tape itself. This simplifies the connection process; you can connect a piece of any length ranging from 3cm to 100m.

Therefore, power for the LED strip can be made from any 12V power supply from consumer electronics.

Main parameters:

number of volts at the output;
rated power;
degree of protection against moisture and dust
Power factor.

DIY LED driver

You can make a simple DIY driver in 30 minutes, even if you don’t know the basics of electronics. As a voltage source, you can use a power supply from consumer electronics with a voltage from 12V to 37V. The power supply from a laptop is especially suitable, it has 18 - 19V and a power from 50W to 90W.

A minimum of parts will be required, all of them are shown in the picture. A heatsink for cooling a powerful LED can be borrowed from a computer. Surely somewhere at home in a closet you have old spare parts from the system unit gathering dust. Best suited from the processor.

To find out the required resistance value, use the current stabilizer calculator for LM317.

Before making a 50W led driver with your own hands, it’s worth searching a little, for example, every diode lamp contains it. If you have a faulty light bulb whose diodes are faulty, then you can use the driver from it.

Low voltage

We will analyze in detail the types of low-voltage ice drivers operating from voltages up to 40 volts. Our Chinese brothers-in-mind offer many options. Voltage stabilizers and current stabilizers are produced on the basis of PWM controllers. The main difference is that the module with the ability to stabilize the current has 2-3 blue regulators on the board, in the form of variable resistors.

The technical characteristics of the entire module are indicated by the PWM parameters of the microcircuit on which it is assembled. For example, the outdated but popular LM2596 according to its specifications holds up to 3 Amperes. But without a radiator it will only handle 1 Ampere.

A more modern option with improved efficiency is the XL4015 PWM controller designed for 5A. With a miniature cooling system it can operate up to 2.5A.

If you have very powerful, super-bright LEDs, then you need an LED driver for LED lamps. Two radiators cool the Schottky diode and the XL4015 chip. In this configuration, it is capable of operating up to 5A with voltage up to 35V. It is advisable that it does not operate in extreme conditions, this will significantly increase its reliability and service life.

If you have a small lamp or pocket spotlight, then a miniature voltage stabilizer with a current of up to 1.5A is suitable for you. Input voltage from 5 to 23V, output up to 17V.

Brightness adjustment

To regulate the brightness of the LED, you can use compact LED dimmers that have appeared recently. If its power is not enough, then you can install a larger dimmer. They usually operate in two ranges: 12V and 24V.

You can control it using an infrared or radio remote control (RC). They cost from 100 rubles for a simple model and from 200 rubles for a model with a remote control. Basically, such remote controls are used for 12V diode strips. But it can easily be connected to a low-voltage driver.

Dimming can be analog in the form of a rotary knob or digital in the form of buttons.

led-obzor.ru

LED DRIVER

We'll look at a really simple and inexpensive high-power LED driver. The circuit is a constant current source, which means it keeps the LED brightness constant no matter what power you use. If a resistor is sufficient to limit the current of small, ultra-bright LEDs, then for powers above 1 watt a special circuit is needed. In general, it is better to power an LED this way than using a resistor. The proposed LED driver is ideal especially for high-power LEDs, and can be used for any number and configuration of them, with any type of power supply. As a test project, we took a 1 watt LED element. You can easily change the driver elements for use with more powerful LEDs, for different types of power supply - power supply, batteries, etc.

LED driver specifications:

Input voltage: 2V to 18V - output voltage: 0.5 less than input voltage (0.5V drop across FET) - current: 20 amps

Details on the diagram:

R2: approximately 100 ohm resistor

R3: resistor is selected

Q2: small NPN transistor (2N5088BU)

Q1: Large N-channel transistor (FQP50N06L)

LED: Luxeon 1-watt LXHL-MWEC

Other driver elements:

A transformer adapter is used as a power source; you can use batteries. To power one LED, 4 - 6 volts is enough. That's why this circuit is convenient because you can use a wide range of power sources and it will always light the same way. A heatsink is not required, since about 200 mA of current flows. If more current is planned, you should install the LED element and transistor Q1 on the heatsink.

Select resistance R3

The LED current is set using R3, it is approximately equal to: 0.5 / R3

Power dissipated by resistor approximately: 0.25 / R3

In this case, the current is set to 225 mA using R3 at 2.2 ohms. R3 has a power of 0.1 W, so a standard 0.25 W resistor is fine. Transistor Q1 will operate up to 18V. If you want more, you need to change the model. Without heatsinks, the FQP50N06L can only dissipate about 0.5 W - that's enough for 200 mA of current with a 3-volt difference between the power supply and the LED.

Functions of transistors in the diagram:

Q1 is used as a variable resistor. - Q2 is used as a current sensor and R3 is a setting resistor that causes Q2 to close when increased current flows. The transistor creates feedback that continuously monitors the current current parameters and keeps it exactly at the specified value.

This circuit is so simple that there is no point in assembling it on a printed circuit board. Simply connect the leads of the parts using a surface-mounted connection.

Forum on power supply of various LEDs

elwo.ru

Drivers for LED light bulbs.

A small laboratory on the topic “which driver is better?” Electronic or on capacitors as ballast? I think everyone has their own niche. I will try to consider all the pros and cons of both schemes. Let me remind you of the formula for calculating ballast drivers. Maybe someone is interested? I will base my review on a simple principle. First, I’ll look at capacitor-based drivers as ballast. Then I'll look at their electronic counterparts. Well, at the end there is a comparative conclusion. Now let's get down to business. We take a standard Chinese light bulb. Here is its diagram (slightly improved). Why improved? This circuit will fit any cheap Chinese light bulb. The only difference will be in the ratings of the radio components and the absence of some resistances (in order to save money).

There are light bulbs with missing C2 (very rare, but it happens). In such light bulbs the pulsation coefficient is 100%. It is very rare to use R4. Although resistance R4 is simply necessary. It will replace the fuse and will also soften the starting current. If it is not in the diagram, it is better to install it. The current through the LEDs determines the rating of capacitance C1. Depending on how much current we want to pass through the LEDs (for DIYers), we can calculate its capacity using formula (1).

I have written this formula many times. I repeat. Formula (2) allows us to do the opposite. With its help, you can calculate the current through the LEDs, and then the power of the light bulb, without having a Wattmeter. To calculate power, we also need to know the voltage drop across the LEDs. You can measure it with a voltmeter, or you can simply count it (without a voltmeter). It's easy to calculate. The LED behaves in the circuit like a zener diode with a stabilization voltage of about 3V (there are exceptions, but very rare). When LEDs are connected in series, the voltage drop across them is equal to the number of LEDs multiplied by 3V (if there are 5 LEDs, then 15V, if 10 - 30V, etc.). It's simple. It happens that circuits are assembled from LEDs in several parallels. Then it will be necessary to take into account the number of LEDs in only one parallel. Let's say we want to make a light bulb with ten 5730smd LEDs. According to the passport data, the maximum current is 150mA. Let's calculate a 100mA light bulb. There will be a power reserve. Using formula (1) we get: C=3.18*100/(220-30)=1.67 μF. The industry does not produce such a capacity, not even the Chinese one. We take the nearest convenient one (we have 1.5 μF) and recalculate the current using formula (2). (220-30)*1.5/3.18=90mA. 90mA*30V=2.7W. This is the rated power of the light bulb. It's simple. In life, of course, it will be different, but not much. It all depends on the actual voltage in the network (this is the first minus of the driver), on the exact capacity of the ballast, the actual voltage drop across the LEDs, etc. Using formula (2) you can calculate the power of light bulbs already purchased (already mentioned). The voltage drop across R2 and R4 can be neglected; it is insignificant. You can connect quite a lot of LEDs in series, but the total voltage drop should not exceed half the mains voltage (110V). If this voltage is exceeded, the light bulb reacts painfully to all voltage changes. The more it exceeds, the more painfully it reacts (this is friendly advice). Moreover, beyond these limits the formula does not work accurately. It is no longer possible to calculate exactly. Now these drivers have a very big advantage. The power of the light bulb can be adjusted to the desired result by selecting capacity C1 (both homemade and already purchased). But then a second minus appeared. The circuit has no galvanic isolation from the network. If you poke an indicator screwdriver anywhere in the switched-on light bulb, it will show the presence of a phase. Touching (the light bulb plugged in) with your hands is strictly prohibited. Such a driver has almost 100% efficiency. Losses are only on diodes and two resistances. It can be made within half an hour (quick). It’s not even necessary to etch the board. I ordered these capacitors: aliexpress.com/snapshot/310648391.html aliexpress.com/snapshot/310648393.html These are the diodes: aliexpress.com/snapshot/6008595825.html

But these schemes have another serious drawback. These are pulsations. Ripple with a frequency of 100 Hz, the result of rectification of the mains voltage.

The shape of different light bulbs will vary slightly. It all depends on the size of the filter capacity C2. The larger the capacity, the smaller the humps, the less pulsation. It is necessary to look at GOST R 54945-2012. And there it is written in black and white that pulsations with a frequency of up to 300 Hz are harmful to health. There is also a formula for calculation (Appendix D).

But that's not all. It is necessary to look at the Sanitary Standards SNiP 23-05-95 “NATURAL AND ARTIFICIAL LIGHTING”. Depending on the purpose of the room, the maximum permissible pulsations are from 10 to 20%. Nothing in life just happens. The result of the simplicity and low cost of light bulbs is obvious. It's time to move on to electronic drivers. Here, too, not everything is so rosy. This is the driver I ordered. This is the link to it at the beginning of the review.

Why did you order this one? Will explain. I wanted to “collectively farm” lamps using 1-3W LEDs myself. I chose it based on price and characteristics. I would be satisfied with a driver for 3-4 LEDs with a current of up to 700mA. The driver must contain a key transistor, which will relieve the driver control chip. To reduce RF ripple, there should be a capacitor at the output. First minus. The cost of such drivers (US $13.75 / 10 pieces) differs more from ballast ones. But here's a plus. The stabilization currents of such drivers are 300mA, 600mA and higher. Ballast drivers would never dream of this (I don’t recommend more than 200mA). Let's look at the characteristics from the seller: ac85-265v" that everyday household appliances." load after 10-15v; can drive 3-4 3w led lamp beads series 600ma But the output voltage range is too small (also a minus). A maximum of five LEDs can be connected in series. At the same time, you can pick up as much as you like. LED power is calculated by the formula: Driver current multiplied by the voltage drop across the LEDs [number of LEDs (from three to five) and multiplied by the voltage drop across the LED (about 3V)]. Another big drawback of these drivers is high RF interference. Some units not only hear FM radio, but also lose reception of digital TV channels when they are operating. The conversion frequency is several tens of kHz. But, as a rule, there is no protection (from interference).

There is something like a “screen” under the transformer. Should reduce interference. It is this driver that produces almost no noise. Why they emit noise becomes clear if you look at the voltage oscillogram on the LEDs. Without capacitors, the Christmas tree is much more serious!

The driver output should contain not only an electrolyte, but also ceramics to suppress RF interference. Expressed his opinion. Usually it costs one or the other. Sometimes it costs nothing. This happens in cheap light bulbs. The driver is hidden inside, making it difficult to file a claim. Let's look at the diagram. But I’ll warn you, it’s for informational purposes only. I applied only the basic elements that we need for creativity (to understand “what’s what”).

There is an error in the calculations. By the way, at low power levels the device also fluctuates. Now let’s count the pulsations (the theory at the beginning of the review). Let's see what our eye sees. I connect a photodiode to the oscilloscope. I combined two pictures into one for ease of perception. The light on the left is off. On the right - the light is on. We look at GOST R 54945-2012. And there it is written in black and white that pulsations with a frequency of up to 300 Hz are harmful to health. And we have about 100Hz. Harmful for the eyes.
I got 20%. It is necessary to look at the Sanitary Standards SNiP 23-05-95 “NATURAL AND ARTIFICIAL LIGHTING”. Can be used, but not in the bedroom. And I have a corridor. You don’t have to look at SNiP. Now let's look at another option for connecting LEDs. This is a wiring diagram for the electronic driver.
Total 3 parallels of 4 LEDs. This is what the Wattmeter shows. 7.1W active power.
Let's see how much reaches the LEDs. I connected an ammeter and a voltmeter to the driver output.
Let's calculate the pure LED power. P=0.49A*12.1V=5.93W. Everything that is missing is taken care of by the driver. Now let's see what our eye sees. The light on the left is off. On the right - the light is on. Pulse repetition frequency is about 100 kHz. We look at GOST R 54945-2012. And there it is written in black and white that only pulsations with a frequency of up to 300 Hz are harmful to health. And we have about 100 kHz. It is harmless to the eyes.

I examined everything, measured everything. Now I will highlight the pros and cons of these circuits: Disadvantages of light bulbs with a capacitor as ballast compared to electronic drivers. -During operation, you categorically cannot touch the circuit elements, they are under phase. -It is impossible to achieve high LED luminescence currents, because This requires large capacitors. And an increase in capacity leads to large inrush currents, damaging the switches. -Large pulsations of the light flux with a frequency of 100 Hz require large filter capacitors at the output. Advantages of light bulbs with a capacitor as ballast compared to electronic drivers. +The circuit is very simple and does not require any special skills in manufacturing. +The output voltage range is simply fantastic. The same driver will work with both one and forty LEDs connected in series. Electronic drivers have a much narrower output voltage range. +Low cost of such drivers, which literally consists of the cost of two capacitors and a diode bridge. +You can make it yourself. Most parts can be found in any shed or garage (old TVs, etc.). +You can regulate the current through the LEDs by selecting the ballast capacity. +Indispensable as an initial LED experience, as the first step in mastering LED lighting. There is one more quality that can be attributed to both pros and cons. When using similar circuits with backlit switches, the LEDs of the light bulb are illuminated. For me personally, this is more of a plus than a minus. I use it everywhere as emergency (night) lighting. I deliberately do not write which drivers are better; each has its own niche. I gave everything I know to the maximum. Showed all the pros and cons of these schemes. And as always, the choice is yours to make. I just tried to help. That's all! Good luck everyone.

mysku.ru

How to choose an LED driver - types and main characteristics

LEDs have become very popular. The main role in this was played by the LED driver, which maintains a constant output current of a certain value. We can say that this device is a current source for LED devices. This current driver, working together with the LED, provides long service life and reliable brightness. Analysis of the characteristics and types of these devices allows you to understand what functions they perform and how to choose them correctly.

What is a driver and what is its purpose?

An LED driver is an electronic device whose output produces a direct current after stabilization. In this case, it is not voltage that is generated, but rather current. Devices that stabilize voltage are called power supplies. The output voltage is indicated on their body. 12 V power supplies are used to power LED strips, LED strips and modules.

The main parameter of the LED driver, which it can provide to the consumer for a long time at a certain load, is the output current. Individual LEDs or assemblies of similar elements are used as a load.

The LED driver is usually powered from a 220 V mains voltage. In most cases, the operating output voltage range is from three volts and can reach several tens of volts. To connect six 3W LEDs, you will need a driver with an output voltage from 9 to 21 V, rated at 780 mA. Despite its versatility, it has low efficiency if a minimum load is applied to it.

When lighting in cars, in the headlights of bicycles, motorcycles, mopeds, etc., when equipping portable lamps, constant voltage power is used, the value of which varies from 9 to 36 V. You can not use a driver for LEDs with low power, but in such In cases, it will be necessary to add a corresponding resistor to the 220 V supply network. Despite the fact that this element is used in household switches, connecting an LED to a 220 V network and counting on reliability is quite problematic.

Key Features

The power that these devices are capable of delivering under load is an important indicator. Don't overload it trying to achieve maximum results. As a result of such actions, drivers for LEDs or the LED elements themselves may fail.

The electronic content of the device is influenced by many reasons:

device protection class;
elemental component that is used for assembly;
input and output parameters;
manufacturer's brand.

The production of modern drivers is carried out using microcircuits using pulse-width conversion technology, which includes pulse converters and current-stabilizing circuits. PWM converters are powered from 220 V, have a high class of protection against short circuits, overloads, as well as high efficiency.

Specifications

Before purchasing an LED converter, you should study the characteristics of the device. These include the following parameters:

output power;
output voltage;
rated current.

LED driver connection diagram

The output voltage is affected by the connection diagram to the power source and the number of LEDs in it. The current value depends proportionally on the power of the diodes and the brightness of their radiation. The LED driver must supply as much current to the LEDs as required to ensure constant brightness. It is worth remembering that the power of the required device should be greater than that consumed by all LEDs. It can be calculated using the following formula:

P(led) – power of one LED element;

n - number of LED elements.

To ensure long-term and stable operation of the driver, the device’s power reserve should be 20–30% of the nominal one.

When performing calculations, you should take into account the color factor of the consumer, as it affects the voltage drop. It will have different meanings for different colors.

Best before date

LED drivers, like all electronics, have a certain service life, which is greatly influenced by operating conditions. LED elements manufactured by well-known brands are designed to last up to 100 thousand hours, which is much longer than power sources. Based on the quality, the calculated driver can be classified into three types:

low quality, with service life up to 20 thousand hours;
with average parameters - up to 50 thousand hours;
converter consisting of components from well-known brands - up to 70 thousand hours.

Many people don’t even know why they should pay attention to this parameter. This will be needed to select a device for long-term use and further payback. For use in domestic premises, the first category is suitable (up to 20 thousand hours).

How to choose a driver?

There are many types of drivers used for LED lighting. Most of the products presented are made in China and do not have the required quality, but they stand out due to their low price range. If you need a good driver, it is better not to go for cheap Chinese products, since their characteristics do not always coincide with those stated, and they rarely come with a warranty. There may be a defect on the microcircuit or rapid failure of the device; in this case, it will not be possible to exchange for a better product or return the funds.

The most commonly chosen option is a boxless driver, powered by 220 V or 12 V. Various modifications allow them to be used for one or more LEDs. These devices can be chosen for organizing research in the laboratory or conducting experiments. For phyto-lamps and household use, drivers for LEDs located in the housing are chosen. Frameless devices win in terms of price, but lose in aesthetics, safety and reliability.

Types of drivers

Devices that supply power to LEDs can be divided into:

pulse;
linear.

Pulse-type devices produce many high-frequency current pulses at the output and operate on the PWM principle, their efficiency is up to 95%. Pulse converters have one significant drawback - strong electromagnetic interference occurs during operation. To ensure a stable output current, a current generator is installed in the linear driver, which plays the role of an output. Such devices have low efficiency (up to 80%), but are technically simple and inexpensive. Such devices cannot be used for high power consumers.

From the above, we can conclude that the power source for LEDs should be chosen very carefully. An example would be a fluorescent lamp that is supplied with a current that exceeds the norm by 20%. There will be virtually no changes in its characteristics, but the performance of the LED will decrease several times.

lampagid.ru

Schemes for connecting LEDs to 220V and 12V

Let's consider ways to connect medium-power ice diodes to the most popular ratings of 5V, 12 volts, 220V. Then they can be used in the manufacture of color and music devices, signal level indicators, smooth switching on and off. I’ve been planning to make a smooth artificial dawn for a long time in order to maintain my daily routine. In addition, dawn emulation allows you to wake up much better and easier.

Read about connecting LEDs to 12 and 220V in the previous article; all methods are discussed, from complex to simple, from expensive to cheap.

1. Types of circuits
2. Designation on the diagram
3. Connecting the LED to a 220V network, diagram
4. Connection to DC voltage
5. The simplest low voltage driver
6. Drivers with power supply from 5V to 30V
7. Turn on 1 diode
8. Parallel connection
9. Serial connection
10. RGB LED connection
11. Turning on COB diodes
12. Connecting SMD5050 for 3 crystals
13. LED strip 12V SMD5630
14. LED strip RGB 12V SMD5050

Types of circuits

There are two types of LED connection diagrams, which depend on the power source:

LED driver with stabilized current;
power supply with stabilized voltage.

In the first option, a specialized source is used, which has a certain stabilized current, for example 300mA. The number of connected LED diodes is limited only by its power. No resistor (resistance) is required.

In the second option, only the voltage is stable. The diode has very low internal resistance; if you turn it on without ampere limitation, it will burn out. To turn it on, you must use a current-limiting resistor. The calculation of the resistor for the LED can be done using a special calculator.

The calculator takes into account 4 parameters:

voltage reduction on one LED;
rated operating current;
number of LEDs in the circuit;
number of volts at the output of the power supply.

If you use inexpensive Chinese-made LED elements, then most likely they will have a wide range of parameters. Therefore, the actual Ampere value of the circuit will be different and the set resistance will need to be adjusted. To check how large the spread of parameters is, you need to turn everything on sequentially. We connect power to the LEDs and then lower the voltage until they barely glow. If the characteristics differ greatly, then some of the LEDs will work brightly, and some will work dimly.

This leads to the fact that some elements of the electrical circuit will have higher power, and because of this they will be more heavily loaded. There will also be increased heating, increased degradation, and lower reliability.

Designation on the diagram

The above two pictograms are used for designation in the diagram. Two parallel arrows indicate that the light is very strong, the number of bunnies in your eyes cannot be counted.

Connecting an LED to a 220V network, diagram

To connect to a 220 volt network, a driver is used, which is a source of stabilized current.

The driver circuit for LEDs comes in two types:

simple on a quenching capacitor;
full-fledged using stabilizer chips;

Assembling a driver on a capacitor is very simple; it requires a minimum of parts and time. The 220V voltage is reduced by a high-voltage capacitor, which is then rectified and slightly stabilized. It is used in cheap LED lamps. The main disadvantage is the high level of light pulsations, which is bad for health. But this is individual, some people don’t notice it at all. It is also difficult to calculate the circuit due to the variation in the characteristics of the electronic components.

A complete circuit using custom ICs ensures better stability in the driver output. If the driver copes well with the load, then the ripple factor will not be higher than 10%, and ideally 0%. In order not to make a driver yourself, you can take it from a faulty light bulb or lamp, if the problem was not with the power supply.

If you have a more or less suitable stabilizer, but the current strength is less or more, then it can be adjusted with a minimum of effort. Find the technical specifications for the chip from the driver. Most often, the number of Amperes at the output is set by a resistor or several resistors located next to the microcircuit. By adding resistance to them or removing one of them, you can obtain the required current strength. The only thing is not to exceed the specified power.

DC connection

3.7V – batteries from phones;
5V – USB chargers;
12V – car, cigarette lighter, consumer electronics, computer;
19V – blocks from laptops, netbooks, monoblocks.

The simplest low voltage driver

The simplest current stabilizer circuit for LEDs consists of a linear microcircuit LM317 or its analogues. The output of such stabilizers can be from 0.1A to 5A. The main disadvantages are low efficiency and strong heating. But this is compensated by the maximum ease of manufacture.

Input up to 37V, up to 1.5 Amperes for the housing indicated in the picture.

To calculate the resistance that sets the operating current, use the current stabilizer calculator on LM317 for LEDs.

Drivers with power supply from 5V to 30V

If you have a suitable power source from any household appliance, then it is better to use a low-voltage driver to turn it on. They can be up or down. A booster will make even 1.5V 5V so that the LED circuit works. A step-down from 10V-30V will make a lower one, for example 15V.

They are sold in a large variety by the Chinese; the low-voltage driver differs in two regulators from a simple Volt stabilizer.

The actual power of such a stabilizer will be lower than what the Chinese indicated. In the module parameters, they write the characteristics of the microcircuit and not the entire structure. If there is a large radiator, then such a module will handle 70% - 80% of what was promised. If there is no radiator, then 25% - 35%.

Particularly popular are models based on LM2596, which are already quite outdated due to low efficiency. They also get very hot, so without a cooling system they do not hold more than 1 Ampere.

XL4015, XL4005 are more efficient, the efficiency is much higher. Without a cooling radiator, they can withstand up to 2.5A. There are very miniature models based on MP1584 measuring 22mm by 17mm.

Turn on 1 diode

The most commonly used are 12 volts, 220 volts and 5V. This is how low-power LED lighting of 220V wall switches is made. Factory standard switches most often have a neon lamp installed.

Parallel connection

When connecting in parallel, it is advisable to use a separate resistor for each series circuit of diodes in order to obtain maximum reliability. Another option is to put one powerful resistor on several LEDs. But if one LED fails, the current on the remaining ones will increase. By whole it will be higher than the nominal or specified value, which will significantly reduce the resource and increase heating.

The rationality of using each method is calculated based on the requirements for the product.

Serial connection

Serial connection when powered from 220V is used in filament diodes and LED strips at 220 volts. In a long chain of 60-70 LEDs, each one drops 3V, which allows it to be connected directly to high voltage. Additionally, only a current rectifier is used to obtain plus and minus.

This connection is used in any lighting technology:

LED lamps for home;
led lamps;
New Year's garlands for 220V;
LED strips 220.

Lamps for the home usually use up to 20 LEDs connected in series; the voltage across them is about 60V. The maximum quantity is used in Chinese corn light bulbs, from 30 to 120 LED pieces. Corns do not have a protective flask, so the electrical contacts on which up to 180V are completely open.

Be careful if you see a long series string, and they are not always grounded. My neighbor grabbed the corn with his bare hands and then recited fascinating poems from bad words.

RGB LED connection

Low-power three-color RGB LEDs consist of three independent crystals located in one housing. If 3 crystals (red, green, blue) are turned on simultaneously, we get white light.

Each color is controlled independently of the others using an RGB controller. The control unit has ready-made programs and manual modes.

Turning on COB diodes

The connection diagrams are the same as for single-chip and three-color LEDs SMD5050, SMD 5630, SMD 5730. The only difference is that instead of 1 diode, a series circuit of several crystals is included.

Powerful LED matrices contain many crystals connected in series and in parallel. Therefore, power is required from 9 to 40 volts, depending on the power.

Connecting SMD5050 for 3 crystals

The SMD5050 differs from conventional diodes in that it consists of 3 white light crystals, and therefore has 6 legs. That is, it is equal to three SMD2835 made on the same crystals.

When connected in parallel using one resistor, reliability will be lower. If one of the crystals fails, the current through the remaining 2 increases. This leads to accelerated burnout of the remaining ones.

By using a separate resistance for each crystal, the above disadvantage is eliminated. But at the same time, the number of resistors used increases by 3 times and the LED connection circuit becomes more complex. Therefore, it is not used in LED strips and lamps.

LED strip 12V SMD5630

A clear example of connecting an LED to 12 volts is an LED strip. It consists of sections of 3 diodes and 1 resistor connected in series. Therefore, it can only be cut in the indicated places between these sections.

LED strip RGB 12V SMD5050

RGB tape uses three colors, each is controlled separately, and a resistor is installed for each color. You can cut only at the indicated location, so that each section has 3 SMD5050 and can be connected to 12 volts.

led-obzor.ru Connection diagrams for sockets and switches

LED driver circuits

Today, probably, not a single apartment or private house can do without LED lighting. And street lighting is gradually changing to economical and durable LED elements. But looking at today’s topic of conversation, the question arises – what does the driver have to do with it (that’s how “driver” is translated from English)? This is the first question that comes to the mind of a person ignorant of LED lighting. In fact, without such a device, light diodes do not work with a voltage of 220 V. Today we will figure out what function the driver for LEDs performs, how to connect this device and whether it is possible to make it yourself.

Read in the article:

Why do we need drivers for LEDs and what are they?

The answer to the question of what is an LED driver is quite simple. This is a device that stabilizes the voltage and gives it the characteristics necessary for the operation of LED elements. To make it clearer, let's draw an analogy with the ballast of a fluorescent lamp, which also cannot work without additional equipment. The only difference is that the driver is compact in size and fits into the body of the light device. In essence, it can be called a stabilizing starting device or frequency converter.

Where are stabilizing devices used for LED elements?

LED drivers for LEDs are used in various fields:

street lighting lamps;
household lighting lamps;
LED strips and various lighting;
office lamps with the form of fluorescent lamps.

Even daytime running lights of cars require the installation of such a device, but here everything is much simpler; you can get by with one resistor. And although the driver for an LED strip (for example) differs in characteristics from the voltage stabilizer of a light bulb, they perform the same function.

Operating principle of a 220V LED lamp driver circuit

The operating principle of the device is to maintain a given current at the output voltage (regardless of its value). This is the difference from a stabilizing power supply, which is responsible for voltage.

Looking at the circuit, we see that the current, passing through the resistance, is stabilized, and the capacitor gives it the desired frequency. Then the rectifying diode bridge comes into play. We get a stabilized forward current on the LEDs, which is again limited by resistors.

Driver Features Worth Considering

The characteristics of the converters required in a particular case are determined based on the parameters of the LED consumers. The main ones can be called:

Driver rated power– this parameter must exceed the total power consumed by the light diodes that will be in its circuit.
Output voltage– depends on the magnitude of the voltage drop across each of the light diodes.
Rated current, which depends on the brightness of the glow and the power consumption of the element.

It is important to know! The voltage drop across an LED depends on its color. For example, if you can connect 16 red LEDs to a 12 V power supply, then the maximum number of green ones will be 9.

Division of LED drivers by device type

Converters can be divided into two types - linear and pulse. Both types are applicable to light diodes, but the differences between them are noticeable in both cost and technical characteristics.

Linear converters are characterized by their simple design and low cost. But such drivers have a significant drawback - the ability to connect only low-power light elements. Part of the energy is spent on heat generation, which contributes to a decrease in efficiency.

Pulse converters are based on the principle of pulse width modulation (PWM) and during their operation, the values of output currents are determined by such a parameter as the duty cycle. This means that there is no change in the pulse frequency, but the duty cycle can vary by values from 10 to 80%. Such drivers allow you to extend the life of light diodes, but have one drawback. During their operation, it is possible to induce electromagnetic interference. Let's try to figure out what this threatens a person with a simple example.

A person living in an apartment or house has a pacemaker. At the same time, in a small room there is a chandelier with many devices operating on pulsed ice drivers for. The pacemaker may begin to malfunction. Of course, this is exaggerated and to create such strong interference you need a lot of lamps that are located at a distance of less than a meter from the pacemaker, but there is still a risk.

How to choose a driver for an LED: some nuances

Before purchasing a converter, calculate the power consumed by the LEDs. The rated power of the device must exceed this figure by 25÷30%. Also, the stabilizer must match the output voltage.

If you plan to place it hidden, it is better to choose a converter without a housing - the cost will be lower with the same technical characteristics.

Important! Drivers made in China usually do not meet the stated specifications. You shouldn’t skimp on purchasing a “made in” converter. It is better to give preference to a Russian manufacturer.

How to connect LED elements to the converter: methods and diagrams

LEDs are connected to the driver in two ways - in series or in parallel. For example, let's take 6 LED emitters with a voltage drop of 2 V. For a serial connection, you will need a 12 V and 300 mA driver. In this case, the glow will be even across all elements.

By connecting the emitters in parallel in a group of 3, we will be able to use a 6 V converter, but at 600 mA. The problem is that due to the uneven voltage drop, one line will glow brighter than the other.

We calculate the characteristics of the converter for LEDs

For an accurate calculation, we first determine the power consumption of the LEDs. Afterwards, the issue with the connection diagram is decided - will it be parallel or serial. The output voltage and rated power of the required converter will depend on this. That's all the work that needs to be done. Now, in an electrical store or on an online resource, we select a driver according to the calculated indicators.

Good to know! When purchasing a converter, ask the seller for a certificate of conformity for the product. If it is missing, it is better to refrain from purchasing.

What is a dimmable LED driver?

Dimmable is a driver for an LED lamp that supports changing input current parameters and is capable of changing output current parameters depending on this. This is achieved by changing the glow intensity of LED emitters. An example would be a controller for an LED strip with remote control. If desired, it becomes possible to “dim” the lighting in the room and give your eyes a rest. This is also appropriate if a child is sleeping in the room.

Dimming is performed from the remote control, or from a standard mechanical stepless switch.

Chinese converters - what's special about them

Chinese friends are famous for their ability to counterfeit equipment so that it becomes impossible to use. The same can be said for drivers. When purchasing a Chinese device, be prepared for inflated declared characteristics, low quality and rapid failure of the converter. If you are going to build your first LED lamp, practice and gain skills in radio electronics, such products are indispensable due to their low cost and ease of execution.

What affects the service life of converters

The causes of converter failure are:

Sudden power surges in the network.
Increased humidity if the device does not meet the degree of protection.
Temperature changes.
Insufficient ventilation.
Increased dustiness.
Incorrect calculation of consumer power.

Any of these reasons can be prevented or corrected. This means that it is within the power of a home craftsman to extend the service life of the stabilizing device.

PT4115 LED driver circuit with dimmer

We will talk about a Chinese manufacturer, which is an exception to the rule. A microcircuit on the basis of which you can assemble a simple converter made by him. The PT4115 microprocessor has good characteristics and is gaining popularity in Russia.

Related article:

If LED lighting and conventional regulators are not suitable, then they are installed, which are slightly different structurally and technically. Today we’ll figure out what they are, how to choose and even make such a device yourself.

The figure shows the simplest PT4115 driver circuit for LEDs, which can be assembled by a novice home craftsman without experience in working with radio electronics. An interesting feature of the microcircuit is an additional output (DIM) that allows the connection of a dimmer.

How to make a driver for LEDs with your own hands

Any novice craftsman can assemble an LED lamp driver circuit. But this will require accuracy and patience. The stabilizing device may not work the first time. To make it clearer to the reader how the work is done, we offer several simple diagrams.

As you can see, there is nothing complicated in the driver circuits for LEDs from a 220 V network. Let's try to look at all stages of work step by step.

Step-by-step instructions for making a DIY LED driver

Photo example	Action to be performed
	To work, we need a regular power supply for the phone. With its help, everything is done quickly and easily.
	After disassembling the charger in our hands, we already have an almost complete driver for three one-watt LEDs, but it needs a little modification.
	We solder a 5 kOhm limiting resistor, which is located near the output channel. It is this that prevents the charger from supplying too much voltage to the cell phone.
	Instead of a limiting resistor, we solder in a tuning resistor, setting it to the same 5 kOhm. Subsequently, we will add voltage to the required level.
	3 LEDs of 1 W each are soldered onto the output channel, connected in series, which gives us a total of 3 W.
	We find the input contacts and unsolder them from the printed circuit board. We don't need them anymore...
	...and in their place we solder a power cord through which 220 V power will be supplied.
	If desired, you can put a 1 Ohm resistor in the gap and set all the indicators with an ammeter. In this case, the attenuation range of the LEDs will be wider.
	After complete assembly, we check the functionality. The output voltage is 5 V, the LEDs are not lit yet.
	By turning the knob on the resistor, we see how the LED elements begin to “flare up”.

Be careful. From such a converter you can get a shock not only of 220 V (from the power cord), but also a shock of about 450 V, which is quite unpleasant (tested on myself).

Very important! Before you check the LED driver for functionality and connect it to a power source, you should once again visually check the correctness of the assembled circuit. Electric shock is life-threatening, and flash from a short circuit can cause damage to the eyes.

Current converters for light diodes: where to buy and what is the cost

Such devices can be purchased at electrical stores or online resources. The second option is more affordable. In addition, many manufacturers offer free shipping. Let's consider some models with an input voltage of 220 V with technical characteristics and costs as of December 2017.

Model	Protection class, IP	Output voltage, V	Power, W	Cost, rub.
DFT-I-40-LD64	20	60-130	45	400
ZF-AC LD49	40	40-70	54	450
XS0812-12W PS12	20	24-44	12	200
PS100 (open)	20	30-36	100	1100
PF4050A PS50	65	27-36	50	500
PF100W LD100	65	23-36	100	1000

Looking at the prices, we can say that making a current converter yourself is more suitable for those for whom this is just a hobby. You can purchase such a device quite inexpensively.

Summarize

When choosing a current converter for LED lamps, you should carefully calculate everything. Any error may lead to a reduction in the service life of the purchased device. Despite the low cost of the stabilizer, it is quite unpleasant to constantly throw money away. Only in this case will the driver serve its intended duration. And when making it yourself, follow the electrical safety rules and be careful and attentive when assembling the circuit.

We hope that the information provided today was useful to our reader. Any questions you may have can be asked in the discussion – we will definitely answer them. Write, ask, share your experience with other readers.

And finally, a short video on today's topic:

LEDs, which have seriously displaced all other light sources in recent years, can be found everywhere today. They are used in apartments and offices, illuminate streets, decorate buildings and interiors. But for proper operation of a semiconductor light source, a high-quality and reliable driver for LEDs is required. Today we will talk about this extremely important unit and figure out why this driver is so necessary, how it works, and even try to make a led driver with our own hands.

What is a driver and why is it needed?

If you look into the English-Russian dictionary, you can find out that a driver is literally a “driver” (driver - driver, English). Where does this strange name come from and what does he drive? In order to understand this, let’s digress a little and talk about LEDs.

A light-emitting diode (LED) is a semiconductor device capable of emitting light under the influence of voltage applied to it. Moreover, for proper operation of the semiconductor, the voltage that provides the optimal current through the crystal must be constant and strictly stabilized. This is especially true for powerful LEDs, which are extremely critical of all kinds of drops and surges in the supply current. As soon as the diode's power supply decreases slightly, the current will drop and, as a result, the light output will decrease. At the slightest excess of the normal current value, the semiconductor instantly overheats and burns out.

The main purpose of the driver is to provide the light-emitting diode with the current necessary for its normal operation. Thus, an LED driver is, in fact, a power supply for LEDs, their “driver”, which ensures long-term and high-quality operation of the semiconductor illuminator.

Expert opinion

Alexey Bartosh

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You will not find a single lighting device that contains a powerful LED that does not have a driver. Therefore, it is so important to understand what drivers are, how they work and what characteristics they should have.

Types of LED Drivers

All drivers for LEDs can be divided according to the principle of current stabilization. Today there are two such principles:

Linear.
Pulse.

Linear stabilizer

Suppose we have a powerful LED at our disposal that needs to be lit. Let's put together a simple diagram:

Diagram explaining the linear principle of current regulation

We set resistor R, which acts as a limiter, to the desired current value - the LED lights up. If the supply voltage has changed (for example, the battery is low), turn the resistor slider and restore the required current. If it has increased, then we reduce the current in the same way. This is exactly what the simplest linear stabilizer does: it monitors the current through the LED and, if necessary, “twists the knob” of the resistor. Only he does this very quickly, managing to react to the slightest deviation of the current from the specified value. Of course, the driver does not have any knob; its role is played by a transistor, but the essence of the explanation does not change.

What is the disadvantage of a linear current stabilizer circuit? The fact is that current also flows through the regulating element and uselessly dissipates power, which simply heats the air. Moreover, the higher the input voltage, the higher the losses. For LEDs with a small operating current, this circuit is suitable and successfully used, but it is more expensive to power powerful semiconductors with a linear driver: the drivers can consume more energy than the illuminator itself.

The advantages of such a power supply include the relative simplicity of the circuit design and the low cost of the driver, combined with high reliability.

Linear driver for powering an LED in a flashlight

Pulse stabilization

We have the same LED, but we’ll assemble a slightly different power circuit:

A diagram explaining the operating principle of a pulse-width stabilizer

Now, instead of a resistor, we have a KH button and a storage capacitor C has been added. We apply voltage to the circuit and press the button. The capacitor begins to charge, and when the operating voltage is reached, the LED lights up. If you continue to hold the button pressed, the current will exceed the permissible value and the semiconductor will burn out. Let's release the button. The capacitor continues to power the LED and gradually discharges. As soon as the current drops below the permissible value for the LED, press the button again, energizing the capacitor.

We sit like this and periodically press the button, maintaining the normal operation of the LED. The higher the supply voltage, the shorter the presses will be. The lower the voltage, the longer the button will have to be pressed. This is the principle of pulse width modulation. The driver monitors the current through the LED and controls a switch assembled on a transistor or thyristor. He does this very quickly (tens and even hundreds of thousands of clicks per second).

At first glance, the work is tedious and complicated, but not for an electronic circuit. But the efficiency of a pulse stabilizer can reach 95%. Even when powered, energy losses are minimal, and key driver elements do not require powerful heat sinks. Of course, switching stabilizers are somewhat more complex in design and more expensive, but all this pays off with high performance, exceptional quality of current stabilization and excellent weight and size characteristics.

This pulse driver is capable of delivering current up to 3 A without any heatsinks.

How to choose a driver for LEDs

Having understood the operating principle of led drivers, all that remains is to learn how to choose them correctly. If you haven't forgotten the basics of electrical engineering you learned in school, then this is a simple matter. We list the main characteristics of the converter for LEDs that will be involved in the selection:

input voltage;
output voltage;
output current;
output power;
degree of protection from the environment.

First of all, you need to decide from what source your LED lamp will be powered. This can be a 220 V network, a car’s on-board network, or any other source of both alternating and direct current. The first requirement: the voltage that you will use must be within the range specified in the driver passport in the “input voltage” column. In addition to the magnitude, you need to take into account the type of current: direct or alternating. After all, in a socket, for example, the current is alternating, but in a car it is constant. The first is usually denoted by the abbreviation AC, the second DC. Almost always this information can be seen on the body of the device itself.

This driver is designed to operate on AC power from 100 to 265 V

Next we move on to the output parameters. Let's assume you have three LEDs with an operating voltage of 3.3 V and a current of 300 mA each (indicated in the accompanying documentation). You decided to make a table lamp, the diode connection circuit is sequential. We add up the operating voltages of all semiconductors, and we get the voltage drop across the entire chain: 3.3 * 3 = 9.9 V. The current with this connection remains the same - 300 mA. This means you need a driver with an output voltage of 9.9 V, providing current regulation at 300 mA.

Expert opinion

Alexey Bartosh

Specialist in repair and maintenance of electrical equipment and industrial electronics.

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Important! All semiconductors operating from the same driver must be of the same type and preferably from the same batch. Otherwise, a scatter in the parameters of the LEDs is inevitable, as a result of which one of them will shine at full intensity, and the second will quickly burn out.

Of course, it will not be possible to find a device for this particular voltage, but this is not necessary. All drivers are designed not for a specific voltage, but for a certain range. Your task is to fit your value into this range. But the output current must exactly correspond to 300 mA. In extreme cases, it can be slightly less (the lamp will not shine so brightly), but never more. Otherwise, your homemade product will burn out immediately or in a month.

Go ahead. We find out what power driver we need. This parameter should at least match the power consumption of our future lamp, and it is better to exceed this value by 10-20%. How to calculate the power of our “garland” of three LEDs? Remember: the electrical power of a load is the current flowing through it multiplied by the applied voltage. We take a calculator and multiply the total operating voltage of all LEDs by current, having first converted the latter to amperes: 9.9 * 0.3 = 2.97 W.

Finishing touch. Design. The device can be either in a housing or without it. The first one, naturally, is afraid of dust and moisture, and in terms of electrical safety it is not the best option. If you decide to build a driver into a lamp whose housing is good protection from the environment, then it will do. But if the lamp body has a bunch of ventilation holes (the LEDs need to be cooled), and the device itself will be in the garage, then it is better to choose a power source in its own housing.

So, we need an LED driver with the following characteristics:

supply voltage - 220 V AC;
output voltage – 9.9 V;
output current – 300 mA;
output power - at least 3 W;
The housing is dust and waterproof.

Let's go to the store and take a look. Here he is:

Driver for powering LEDs

And not just suitable, but ideally suited to the needs. A slightly reduced output current will extend the life of the LEDs, but this will have absolutely no effect on the brightness of their glow. Power consumption will drop to 2.7 W - there will be a reserve of driver power.

Expert opinion

Alexey Bartosh

Specialist in repair and maintenance of electrical equipment and industrial electronics.

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If you have a very large number of LEDs, then when connected in series, their total voltage may exceed the maximum possible for existing drivers. In this case, refer to the section Diagram for connecting the driver to the LEDs, which is located at the end of this article.

What are the differences between a driver for LEDs and a power supply for LED strip?

There is an opinion that power supplies are something different than a regular LED driver. Let’s try to clarify this issue, and at the same time learn how to choose the right driver for the LED strip. An LED strip is a flexible substrate on which the same LEDs are located. They can stand in 2, 3, 4 rows, it’s not that important. It is more important to understand how they are connected to each other.

All semiconductors on the tape are divided into groups of 3 LEDs, connected in series through a current-limiting resistor. All groups, in turn, are connected in parallel:

Electrical diagram of one section (left) and the entire LED strip

The tape is sold in reels, usually 5 m long, and is designed for an operating voltage of 12 or 24 V. In the latter case, each group will have not 3, but 6 LEDs. Let's assume you bought a 12 V tape with a specific power consumption of 14 W/m. Thus, the total power consumed by the entire bobbin will be 14 * 5 = 70 W. If you don't need such a long one, you can cut off the unnecessary part, provided that you cut it between sections. For example, you cut off half. What characteristics will change? Only power consumption: it will be halved.

Expert opinion

Alexey Bartosh

Specialist in repair and maintenance of electrical equipment and industrial electronics.

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Important! Do not forget that you can cut the LED strip only between sections of 3 LEDs (for 24-volt there will be 6), which are clearly visible. In the picture below I have marked them with arrows.

The places where sections separate are clearly visible and are even marked with scissor icons

Is it necessary to limit and stabilize the current through a regular LED? Of course, otherwise it will burn. But we completely forgot about the resistor installed in each section of the tape. It serves to limit the current and is selected in such a way that when exactly 12 volts are supplied to the section, the current through the LEDs will be optimal. The task of the LED strip driver is to keep the supply voltage strictly at 12 V. The rest is taken care of by the current-limiting resistor.

Thus, the main difference between the LED strip power supply and a conventional LED driver is a clearly fixed output voltage of 12 or 24 V. Here it is no longer possible to use a conventional driver with an output voltage, say, from 9 to 14 V.

The remaining criteria for choosing a power supply for an LED strip are as follows:

input voltage. The selection method is the same as for a conventional driver: the device must be designed for the input voltage and the type of current with which you will power the LED strip;
output power. The power of the power supply must be at least 10% higher than the power of the tape. At the same time, you should not take too much stock: the efficiency of the entire structure decreases;
environmental protection class. The technique is the same as for the LED driver (see above): dust and moisture should not get into the device.

A driver for an LED strip is nothing more than a high-quality, but ordinary voltage stabilizer. It produces a strictly fixed voltage, but does not monitor the output current at all. If you wish and for experimentation, you can use, for example, a power supply from a PC (12 V bus) instead. The brightness and durability of the tape will not be affected by this.

Diagram of connecting the driver to the LEDs

Connecting the driver to the LEDs is simple, anyone can do it. All markings are applied to its body. You apply input voltage to the input wires (INPUT), and connect a line of LEDs to the output wires (OUTPUT). The only thing is that it is necessary to maintain polarity, and I will dwell on this in more detail.

Input Polarity (INPUT)

If the voltage supplying the driver is constant, then the pin marked “+” must be connected to the positive pole of the power source. If the voltage is alternating, then pay attention to the markings of the input wires. The following options are possible:

Marking “L” and “N”: a phase must be applied to the “L” terminal (located using an indicator screwdriver), and a zero must be applied to the “N” terminal.
Marking “~”, “AC” or absent: polarity does not need to be observed.

Output polarity (OUTPUT)

Polarity is always observed here! The positive wire is connected to the anode of the first LED, the negative wire to the cathode of the last one. The LEDs themselves are connected to each other: the anode of the next one to the cathode of the previous one.

Diagram of connecting the driver to a garland of three LEDs connected in series

If you have a lot of LEDs (say, 12 pieces), then they will have to be divided into several identical groups, and these groups will have to be connected in parallel. Please note that the total power consumed by the luminaire will be the sum of the powers of all groups, and the operating voltage will correspond to the voltage of one group.

DIY linear driver for LEDs

Let's finish with the theory, move on to practice and try to assemble a linear driver with our own hands. The easiest way to solve this problem is with the help of the widely used integrated stabilizer KR142EN12A (its imported analogue is LM317). You can find it in any relevant store, and it costs around 20 rubles. Required materials and tools: soldering iron, tester and wires.

This microcircuit is designed for input voltage up to 40 V, can withstand current up to 1.5 A and, most importantly, has built-in protection against overload, short circuit and overheating. True, this is a voltage stabilizer, and the driver must stabilize the current. But we will solve this issue by slightly changing the typical circuit diagram for connecting the microcircuit.

Universal driver for LEDs on an integrated stabilizer

Here the microcircuit is used as a regulating element that stabilizes the current at a given level. What value will this current be? It all depends on the resistance of resistor R1, the value of which is calculated using a simple formula: R = 1.2/I, where:

R – resistance in ohms;
I – required current in amperes.

Let's try to build a driver for those LEDs from which we made a table lamp at the beginning of the article. So, we need a driver that produces a stabilized current of 300 mA at a voltage of 9.9 V. We calculate the value of resistor R1: 1.2/0.3= 4 Ohms. Since the resistor is in the current circuit, we select its power at least 4 W.

Resistors that are used in almost all TVs as power supply suppressors (these are available in any store) are perfect here. They have a power of 2 W and a resistance of 1-2 ohms. If the resistors are one-ohm, then you will need 4 pieces, if two-ohm - 2 pieces. We connect them in series so that the resistances add up.

We attach the microcircuit to a small radiator and connect a chain of three series-connected LEDs to the output of our driver, observing the polarity. You can turn it on. But where? What is the input voltage of this driver? This is where the fun begins. The input voltage should be at least 2-3 volts more than what the LEDs need, but no more than 40 V - the microcircuit cannot withstand more.

In our particular case, the LEDs need 9.9 V. This means that a constant voltage of 12 to 40 V can be supplied to the input. Moreover, this voltage can be unstabilized. A car battery, a laptop or PC power supply, or a step-down transformer with a diode bridge are suitable. We connect, observing the polarity, and our flashlight is ready!

Expert opinion

Alexey Bartosh

Specialist in repair and maintenance of electrical equipment and industrial electronics.

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What about the output voltage? There is no need to worry about this. As soon as the driver stabilizes the current at a given level, the required voltage on the LEDs will be established without our help. If you don't believe it, take a tester and measure it.

This is where our conversation about led drivers ends. I hope that now you not only know how this important unit works, but you can also choose it correctly, connect it, and, if necessary, even assemble it yourself.