home Tips Calculation of the driver for the LED lamp. Drivers for LEDs: types, characteristics and criteria for selecting devices. LEDs for LED drivers

Calculation of the driver for the LED lamp. Drivers for LEDs: types, characteristics and criteria for selecting devices. LEDs for LED drivers

One of the conditions for the reliable operation of LEDs is high-quality stable DC power supply of a given voltage.

Led-driver - just designed for this.

Consider the main purpose and principle of its operation, what main parameters it is characterized by, what varieties exist, how it differs from a standard power supply, how to choose the right one and what are the main connection schemes.

Led-driver is a stabilizing module. Without it, none of the currently produced LED elements is able to work - from the weakest to the most powerful. It must be strictly matched to the load of the assembled circuit, especially when the fixtures have a serial connection. In this case, the voltage drop in each particular led light source may vary (as it depends on the factory assembly parameters), while the current strength should remain the same for all of them.

The role of the led-driver cannot be overestimated. After all, with the slightest increase in power supply parameters, the semiconductor crystal instantly heats up and burns out. On the other hand, when the characteristics of the network decrease, the light output suffers and the luminosity declared by the manufacturer decreases. Therefore, it is so important to choose the right driver for LEDs.

Principle of operation

The main purpose of the led-driver is to maintain the stability of the output current. Most of the drivers produced today for led elements are assembled on the principle of pulse-width converters. They include pulse transformer and microcircuits stabilizing electric current. Such devices are designed to be powered from a household network with a voltage of 220 volts, are characterized high rate efficiency and have a special fuse against overload and short circuit.

There are also linear type led-drivers. The principle of its operation is based on the stabilization of the current as it passes through a transistor with a p-channel. In contrast to the modification described above, it is a cheaper, simpler and inefficient analogue. During operation, such drivers can get very hot, and therefore are not used for circuits with powerful LED elements.

Main characteristics

Among the main characteristics of the led-driver, the following three are of particular importance to its performance parameters:

Output voltage.
Rated current.
Power.

The first factor is influenced by the value of the voltage drop of the ice element itself, as well as the way it is connected. If a parallel circuit is used, then the voltage on all LEDs will be the same. A different result will be when using a serial circuit. Here, the value of this parameter should be equal to the total voltage drop of all elements of the chain.

The value of the rated current of the led-driver is directly dependent on the brightness and power of the led-lamps. The driver must supply a current of such strength that their light intensity is equal to that declared by the manufacturer.

The power or output load of the led-driver must not be lower than the total value of the same parameter for all participants in the circuit. For example, if there are 10 LEDs of 2 W in the circuit, then their sum will be equal to 20 W. At the same time, a buffer of 20-30% (power reserve) must be added to the calculated load. In this case, it turns out: 20 W + (20 x 0.3) 6 W = 26 W.

Important! When calculating the power of a led-driver, it is also necessary to take into account the color of the led element, since crystals of different colors with equal brightness and current strength have different voltage drops, and hence power. For example, two 359 mA LEDs red and green each take 1.9-2.4 V and 3.3-3.9 V, respectively, and therefore have 0.75 and 1.25 watts, respectively.

Types of LED Drivers

There are two main types of led-driver - a pulse type and a linear type. The difference between them lies in the principle of stabilization electric current, which is expressed in the main characteristics, areas of application and service life. Let's consider them in more detail.

Linear stabilizer

Linear led-driver performs the function of the simplest automatic resistor. At the slightest change in current strength, it instantly restores its set value at the output. The role of such a device is performed by a transistor. Regardless of how the characteristics of the external supply network change, its internal value remains constant.

Read also The device and principle of operation of the diode with direct and reverse switching

The advantage of such a system lies in the simplicity of its design, low cost and stability. However, the main disadvantage of a linear stabilizer is the loss of a share of power due to its conversion into thermal energy. In this case, there is a direct relationship between the absolute value of the input voltage and the flow. Therefore, the linear type led-driver is suitable for low power LEDs. It is not used on led elements with large current strength parameters, since the drivers themselves will consume more energy than the semiconductor crystals themselves.

Pulse stabilization

The pulse led-driver is a pulse capacitor with an automatic device for turning on / off the electric current located in front of it. As soon as the voltage in it reaches the operating value, and the LED bus or lamp lights up, the switch is activated and the current stops - in order to avoid further potential growth and to avoid burning out the crystal in the lamp.

In the future, as the potential is gradually consumed in the storage capacitor, a current is turned on to recharge it so that the lantern does not fade. The make-up time and the shutdown period may vary depending on the voltage in the external network. The role of such a regulator-switch operating in an automatic programmed mode is performed by a pulsed led-driver.

Its efficiency is close to 100%. Therefore, it is used even on very powerful spotlights. At the same time, the led-driver in its circuit is so efficient that its case does not even require special heatsinks to remove heat. Among their main disadvantages are the complexity of the device and the high price. On the other hand, a number of advantages such as high performance, small dimensions and weight, and high quality of the output current stability easily offset them.

What is the difference between LED driver and led strip power supply

The question of whether the led-driver for an LED lamp and a strip differs from each other worries all those who want to make a backlight from Supplies. It can only be answered by first understanding what a led strip is, what elements it consists of and how it all works.

Ordinary ice tape is a set of LEDs interconnected in one or more rows according to the electrical circuit and fixed on a special elastic substrate. In turn, inside they are divided into groups of 3 or 6 crystals. All of them are connected through a current-limiting resistor in a series circuit. In this case, the groups are connected to each other in parallel.

The operating voltage for ice strips is 12 or 24 volts. In this case, the entire tape is divided into sections. Each of them has its own resistor - to limit and stabilize the current. Thus, the task of the power supply is to convert the output voltage strictly to 12 or 24 volts - no more and no less. This is precisely the difference from the usual led-driver, which can be designed for any other operating voltage (as a rule, this range, for example, from 8 to 13 volts). At the same time, the ice tape driver does not monitor the parameters of the output current at all - this is the task of the resistors in each group of LEDs.

How to choose

The correct selection of a led-driver to power an LED should take into account the following parameters:

Input voltage value.
The value of the output voltage.
output current.
output power.
Moisture and dust protection.

The basic principle of choosing the right driver for an LED is to start calculating its characteristics only after the exact number of light sources and their main parameters (primarily power) in the planned circuit are known. In addition, it is necessary to know in advance the operating conditions of electrical equipment - indoors or outdoors, what are the parameters of temperature and humidity fluctuations, as well as the effect of precipitation.

Important! When choosing a led-driver, you need to know exactly from which source it will be powered. This can be a 220 volt household network, or a car battery, or a diesel power plant, etc. The voltage range from them must fit into the operating input voltage of the ice driver. You also need to know in advance the nature of the incoming current - it is constant or variable.

Next, you need to correctly calculate the output parameters for the led-driver. First of all, it's tension. It is calculated as follows - it is necessary to sum up the value of all ice elements in the chain. For example, if there are 5 diodes of 3 volts in the circuit, the total will be 5x3 \u003d 15 volts. In this case, it must be taken into account that the connection of the lamps will be consistent. In the input characteristics there is another value - the current strength. It will be the same for all lamps.

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. Such a current driver, working together with the LED, ensures a long service life and reliable brightness. An 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?

Driver for LED is electronic device, at the output of which D.C. after stabilization. In this case, it is not a voltage that is formed, but a current. Devices that stabilize the voltage are called power supplies. The output voltage is indicated on their case. 12 V power supplies are used to power LED strips, LED strips and modules.

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

The LED driver is usually powered by 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 of 9 to 21 V, rated at 780 mA. With its versatility, it has a low efficiency, if you include a minimum load on it.

When lighting in cars, headlights of bicycles, motorcycles, mopeds, etc., portable lamps are equipped with a constant voltage supply, the value of which varies from 9 to 36 V. You can not use a driver for LEDs with low power, but in such cases, it will be necessary to introduce an appropriate resistor into the 220 V supply network. Despite the fact that this element is used in household switches, it is rather problematic to connect the LED to the 220 V network and rely on reliability.

Key Features

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

The electronic filling of the device is affected by many reasons:

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

The manufacture of modern drivers is carried out using microcircuits using pulse-width conversion technology, which include 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 a converter for LEDs, you should study the characteristics of the device. These include the following options:

output power;
output voltage;
rated current.

LED driver connection diagram

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

P(led) – power of one LED element;

n- the number of LED elements.

To ensure a long and stable operation drivers should take into account the power reserve of the device in 20-30% of the nominal.

When performing the calculation, the color factor of the consumer should be taken into account, as it affects the voltage drop. Different colors will have different meanings.

Best before date

LED drivers, like all electronics, have a certain service life, which is strongly influenced by operating conditions. LED elements made by well-known brands are designed to work up to 100,000 hours, which is much longer than power supplies. According to the quality, the calculated driver can be classified into three types:

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

Many do not even know why 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 presented products are made in China and do not have the required quality, but stand out at the same time with a low price range. If needed good driver, it is better not to chase the cheapness of Chinese production, since their characteristics do not always match the declared ones, and they rarely come with a guarantee. There may be a defect on the microcircuit or a quick failure of the device, in which case it will not be possible to exchange for a better product or return the funds.

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

Types of drivers

Devices that power LEDs can be conditionally divided into:

impulse;
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 a low efficiency (up to 80%), but at the same time they are technically simple and inexpensive. Such devices cannot be used for high power consumers.

From the above, we can conclude that the power supply for LEDs should be chosen very carefully. An example would be Fluorescent Lamp, which is supplied with a current exceeding the norm by 20%. There will be practically no changes in its characteristics, but the performance of the LED will decrease several times.

Recently, consumers are increasingly interested in LED lighting. The popularity of LED lamps is quite justified - new technology lighting does not emit ultraviolet radiation, is economical, and the service life of such lamps is more than 10 years. In addition, with the help of LED elements in home and office interiors, it is easy to create original light textures on the street.

If you decide to purchase such devices for your home or office, then you should know that they are very demanding on the parameters of electrical networks. For optimal lighting performance, you will need an LED driver. Since the construction market is full of devices of both different quality and pricing policy, before you purchase LED devices and a power supply for them, it will not be superfluous to familiarize yourself with the basic advice given by experts in this matter.

To begin with, let's consider why such a device as a driver is needed.

What is the purpose of drivers?

A driver (power supply) is a device that performs the functions of stabilizing the current flowing through the LED circuit, and is responsible for ensuring that the device you bought will work for the number of hours guaranteed by the manufacturer. When choosing a power supply, you must first thoroughly study its output characteristics, including current, voltage, power, coefficient of performance (COP), as well as the degree of its protection and external factors.

For example, the brightness of the LED depends on the current flow characteristics. The digital designation of the voltage reflects the range in which the driver operates with possible power surges. And of course, the higher the efficiency, the more efficiently the device will work, and its service life will be longer.

Where are LED drivers used?

An electronic device - a driver - is usually powered by a 220V electrical network, but is designed to work with very low voltages of 10, 12 and 24V. The operating output voltage range, in most cases, is from 3V to several tens of volts. For example, you need to connect seven 3V LEDs. In this case, you will need a driver with an output voltage of 9 to 24V, which is rated for 780 mA. Please note that, despite the versatility, such a driver will have a low efficiency if you give it a minimum load.

Whether you need to install lighting in a car, insert a lamp into the headlight of a bicycle, a motorcycle, one or two small street lamps or a hand lamp, a power supply from 9 to 36V will be enough for you.

More powerful LED drivers will need to be chosen if you intend to connect an LED system consisting of three or more devices outdoors, have chosen it to decorate your interior, or if you have office table lamps that work at least 8 hours a day .

How does the driver work?

As we have already said, the LED driver acts as a current source. The voltage source creates a certain voltage at its output, ideally independent of the load.

For example, let's connect a 40 ohm resistor to a 12 V source. A current of 300mA will flow through it.

Now let's turn on two resistors at once. The total current will be already 600mA.

The power supply maintains a given current at its output. The voltage may change. We also connect a 40Ω resistor to the 300mA driver.

The power supply will create a voltage drop of 12V across the resistor.

If you connect two resistors in parallel, the current will also be 300mA, and the voltage will drop by half.

What are the main characteristics LED drivers?

When selecting a driver, be sure to pay attention to parameters such as output voltage, power (current) consumed by the load.

- The output voltage depends on the voltage drop across the LED; number of LEDs; on the connection method.

- The current at the output of the power supply is determined by the characteristics of the LEDs and depends on their power and brightness, quantity and color scheme.

Let's dwell on the color characteristics of LED - lamps. From this, by the way, depends on the power of the load. For example, the average power consumption of a red LED varies within 740 mW. In green, the average power will already be about 1.20 watts. Based on these data, you can calculate in advance what kind of driver power you need.

P=Pled x N

where Pled is the power of the LED, N is the number of connected diodes.

Another important rule. D For stable operation of the power supply, the power margin must be at least 25%. That is, the following relation must hold:

Pmax ≥ (1.2…1.3)xP

where Pmax is the maximum power of the power supply.

How to connect LEDs correctly?

You can connect LEDs in several ways.

The first way is a sequential introduction. Here you need a driver with a voltage of 12V and a current of 300mA. With this method, the LEDs in the lamp or on the tape light up equally bright, but if you decide to connect more LEDs, you will need a driver with a very high voltage.

The second way is parallel connection. A 6V power supply is suitable for us, and the current will be consumed about twice as much as with a serial connection. There is also a drawback - one circuit can shine brighter than the other.

Series-parallel connection - found in spotlights and other powerful lamps operating on both direct and alternating voltage.

The fourth way is to connect the driver in series by two. It is the least preferred.

There is also a hybrid option. It combines the advantages of series and parallel connection of LEDs.

Experts advise choosing a driver before you buy LEDs, and it is also advisable to pre-determine their connection scheme. So the power supply will work more efficiently for you.

Linear and pulse drivers. What are their operating principles?

Today, for LED lamps and strips, linear and impulse drivers.
The linear output is a current generator, which provides voltage stabilization without creating electromagnetic interference. Such drivers are easy to use and not expensive, but their low efficiency limits their scope.

Pulse drivers, on the contrary, have a high efficiency (about 96%), and even compact. A driver with these characteristics is preferable to use for portable lighting devices, which allows you to increase the operating time of the power supply. But there is also a minus - due to the high level of electromagnetic interference, it is less attractive.

Need a 220V LED driver?

Linear and pulse drivers are available for inclusion in the 220V network. Moreover, if power supplies have galvanic isolation (transfer of energy or signal between electrical circuits without electrical contact between them), they demonstrate a high efficiency, reliability and safety in operation.

Without galvanic isolation, the power supply will cost you less, but will not be as reliable, requiring care when connecting due to the danger of electric shock.

When selecting parameters for power, experts recommend opting for LED drivers with a power that exceeds the required minimum by 25%. Such a power reserve will not allow the electronic device and the power supply to quickly fail.

Should I buy Chinese drivers?

Made in China - today on the market you can find hundreds of drivers of various characteristics made in China. What are they? Basically, these are devices with a pulsed current source of 350-700mA. Low price and the presence of galvanic isolation allow such drivers to be in demand among buyers. But there are also disadvantages of a Chinese-made device. Often they do not have a case, the use of cheap elements reduces the reliability of the driver, and there is also no protection against overheating and fluctuations in the mains.

Chinese drivers, like many products manufactured in the Middle Kingdom, are short-lived. Therefore, if you want to install a quality lighting system that will last you for a single year, it is best to buy an LED converter from a trusted manufacturer.

What is the lifespan of a led driver?

Drivers, like any electronics, have their own lifespan. The warranty period of the LED driver is 30,000 hours. But do not forget that the operating time of the device will also depend on the instability of the mains voltage, the level of humidity and temperature differences, and the influence of external factors on it.

Incomplete loading of the driver also reduces the life of the device. For example, if an LED driver is rated at 200W and operates at a load of 90W, half of its power is returned to the electrical network, causing it to overload. This provokes frequent power failures and the device may burn out, serving you for only a year.

Follow our advice and then you will not have to change LED devices often.

An integral part of any quality LED lamp or luminaire is the driver. With regard to lighting, the term "driver" should be understood as an electronic circuit that converts the input voltage into a stabilized current of a given value. The functionality of the driver is determined by the width of the input voltage range, the ability to adjust the output parameters, susceptibility to drops in the supply network and efficiency.

The quality indicators of the lamp or the lamp as a whole, the service life and cost depend on the listed functions. All power sources (PS) for LEDs are conditionally divided into linear and pulse type converters. Linear IP can have a current or voltage stabilization unit. Often, radio amateurs construct circuits of this type with their own hands on the LM317 chip. Such a device is easy to assemble and has a low cost. But, due to the very low efficiency and the obvious limitation on the power of connected LEDs, the prospects for the development of linear converters are limited.

Switching drivers can be over 90% efficient and highly immune to mains interference. Their power consumption is ten times less than the power delivered to the load. Due to this, they can be made in a sealed case and are not afraid of overheating.

The first switching regulators had a complex device without no-load protection. Then they were modernized and, in connection with the rapid development LED technology, specialized microcircuits with frequency and pulse-width modulation appeared.

Power supply circuit for LEDs based on a capacitor divider

Unfortunately, in the design of cheap 220V LED lamps from China, neither a linear nor a switching stabilizer is provided. Motivated by the exceptionally low price of the finished product, the Chinese industry was able to simplify the power scheme as much as possible. Calling it a driver is not correct, since there is no stabilization here. The figure shows that the electrical circuit of the lamp is designed to operate from a 220V network. The alternating voltage is lowered by the RC circuit and fed to the diode bridge. Then the rectified voltage is partially smoothed by the capacitor and fed through the current-limiting resistor to the LEDs. This circuit does not have galvanic isolation, that is, all elements are constantly at high potential.

As a result, frequent drops in the mains voltage leads to the flickering of the LED lamp. And vice versa, the overvoltage of the network causes an irreversible aging process of the capacitor with loss of capacity, and, sometimes, causes it to break. It is worth noting that another, serious negative side of this scheme is the accelerated degradation of LEDs due to unstable supply current.

Driver circuit on CPC9909

Modern pulse drivers for LED lamps have a simple circuit, so it can be easily made even with your own hands. Today, to build drivers, a number of integrated circuits are produced specifically for driving high-power LEDs. To simplify the task for lovers of electronic circuits, the developers of integrated drivers for LEDs in the documentation provide typical switching circuits and calculations of the strapping components.

General information

The American company Ixys has launched the release of the CPC9909 chip, designed to control LED assemblies and high brightness LEDs. The driver based on CPC9909 has small dimensions and does not require large financial investments. IC CPC9909 is manufactured in a planar design with 8 pins (SOIC-8) and has a built-in voltage regulator.

Due to the presence of a stabilizer, the input voltage operating range is 12-550V from a DC source. The minimum voltage drop across the LEDs is 10% of the supply voltage. Therefore CPC9909 is ideal for connecting high voltage LEDs. The IC works perfectly in the temperature range from -55 to +85°C, which means it is suitable for designing LED lamps and outdoor lighting fixtures.

Pin assignment

It is worth noting that with the help of the CPC9909, you can not only turn on and off a powerful LED, but also control its glow. To learn about all the possibilities of the IC, consider the purpose of its conclusions.

VIN. Designed to supply voltage.
CS. Designed to connect an external current sensor (resistor), which sets the maximum LED current.
GND. General output of the driver.
GATE. Microchip output. Provides a modulated signal to the gate of the power transistor.
PWMD. Low frequency dimming input.
VDD. Output for supply voltage regulation. In most cases, it is connected through a capacitor to a common wire.
L.D. Designed to set analog dimming.
R.T. Designed to connect the time setting resistor.

Scheme and its principle of operation

A typical 220V powered CPC9909 is shown in the figure. The circuit is capable of driving one or more high power or high brightness LEDs. The circuit can be easily assembled with your own hands, even at home. The finished driver does not need to be adjusted, taking into account the competent choice of external elements and compliance with the rules for their installation.
The 220V LED lamp driver based on the CPC9909 works according to the pulse-frequency modulation method. This means that the pause time is a constant value (time-off=const). The alternating voltage is rectified by a diode bridge and smoothed by a capacitive filter C1, C2. Then it enters the VIN input of the microcircuit and starts the process of generating current pulses at the GATE output. The output current of the microcircuit controls the power transistor Q1. At the moment of the open state of the transistor (the “time-on” pulse time), the load current flows through the circuit: “+diode bridge” - LED - L - Q1 - R S - “-diode bridge”.
During this time, the inductor accumulates energy in order to give it to the load during the pause. When the transistor closes, the energy of the inductor provides the load current in the circuit: L - D1 - LED - L.
The process is cyclic, as a result of which the current through the LED has sawtooth. The largest and smallest value of the saw depends on the inductance of the inductor and the operating frequency.
The pulse frequency is determined by the resistance value RT. The amplitude of the pulses depends on the resistance of the resistor RS. LED current stabilization occurs by comparing the internal reference voltage of the IC with the voltage drop across R S . The fuse and thermistor protect the circuit from possible emergency conditions.

Calculation of external elements

Frequency setting resistor

The pause duration is set by an external resistor R T and is determined by a simplified formula:

pause t =R T /66000+0.8 (μs).

In turn, the pause time is related to the duty cycle and frequency:

pause t = (1-D) / f (s), where D is the duty cycle, which is the ratio of pulse time to period.

current sensor

The resistance value R S sets the amplitude value of the current through the LED and is calculated by the formula: R S \u003d U CS / (I LED +0.5 * I L pulse), where U CS is the calibrated reference voltage equal to 0.25V;

I LED - current through the LED;

I L pulse - the value of the load current ripple, which should not exceed 30%, that is, 0.3 * I LED.

After conversion, the formula will take the form: R S \u003d 0.25 / 1.15 * I LED (Ohm).

The power dissipated by the current sensor is determined by the formula: P S =R S *I LED *D (W).

A resistor with a power margin of 1.5-2 times is accepted for installation.

Throttle

As you know, the inductor current cannot change abruptly, increasing during the pulse and decreasing during the pause. The task of a radio amateur is to select a coil with an inductance that provides a compromise between the quality of the output signal and its dimensions. To do this, remember the level of ripple, which should not exceed 30%. Then you need an inductor with a nominal value of:

L=(US LED *t pauses)/ I L pulse, where U LED is the voltage drop across the LED(s) taken from the I-V curve.

Power filter

Two capacitors are installed in the power circuit: C1 - to smooth the rectified voltage and C2 - to compensate for frequency interference. Since the CPC9909 operates over a wide input voltage range, there is no need for a large capacity of electrolytic C1. 22 uF will be enough, but more is possible. The capacitance of metal-film C2 for a circuit of this type is standard - 0.1 μF. Both capacitors must withstand a voltage of at least 400V.

However, the IC manufacturer insists on mounting capacitors C1 and C2 with low equivalent series resistance (ESR) to avoid the negative effect of high-frequency noise that occurs when switching the driver.

Rectifier

The diode bridge is selected based on the maximum forward current and reverse voltage. For operation in a 220V network, its reverse voltage must be at least 600V. The calculated forward current directly depends on the load current and is defined as: I AC \u003d (π * I LED) / 2√2, A.

The resulting value must be multiplied by two to increase the reliability of the circuit.

Selecting the Rest of the Schematic Elements

Capacitor C3 installed in the power circuit of the microcircuit must be 0.1 uF with low value ESR, similar to C1 and C2. The unused PWMD and LD pins are also connected to a common wire through C3.

Transistor Q1 and diode D1 are pulsed. Therefore, the choice should be made taking into account their frequency properties. Only elements with a short recovery time will be able to contain the negative effects of transients at the moment of switching at a frequency of about 100 kHz. The maximum current through Q1 and D1 is equal to the amplitude value of the LED current, taking into account the selected fill factor: I Q1 \u003d I D1 \u003d D * I LED, A.

The voltage applied to Q1 and D1 is pulsed, but no more than the rectified voltage, taking into account the capacitive filter, that is, 280V. The choice of power elements Q1 and D1 should be made with a margin, multiplying the calculated data by two.

The fuse protects the circuit from an emergency short circuit and must withstand the maximum load current for a long time, including impulse noise.

I FUSE \u003d 5 * I AC, A.

Installing an RTH thermistor is needed to limit the inrush current of the driver when the filter capacitor is discharged. With its resistance, RTH should protect the diodes of the bridge rectifier from breakdown in the initial seconds of operation.

R TH \u003d (√2 * 220) / 5 * I AC, Ohm.

Other options for enabling CPC9909

Soft start and analog dimming

If desired, the CPC9909 can provide a soft turn on of the LED when its brightness gradually increases. Soft start is implemented using two fixed resistors connected to the LD terminal, as shown in the figure. This solution allows you to extend the life of the LED.

Also, the LD pin allows you to implement the analog dimming function. To do this, the 2.2 kΩ resistor is replaced with a 5.1 kΩ variable resistor, thereby smoothly changing the potential at the LD pin.

Pulse dimming

You can control the glow of the LED by applying rectangular pulses to the PWMD (pulse width modulation dimming) pin. For this, a microcontroller or a pulse generator is used with mandatory separation through an optocoupler.

In addition to the considered version of the driver for LED lamps, there are similar circuit solutions from other manufacturers: HV9910, HV9961, PT4115, NE555, RCD-24, etc. Each of them has its strengths and weaknesses, but in general, they successfully cope with the assigned load when assembling by hand.

Homemade driver for LEDs from a 220V network. Schemes of ice drivers

Do-it-yourself LED driver: simple diagrams with descriptions

The use of LEDs as light sources usually requires a specialized driver. But it happens that the necessary driver is not at hand, but you need to organize the backlight, for example, in a car, or test the LED for the brightness of the glow. In this case, you can make a driver for LEDs with your own hands.

How to make an LED driver

The diagrams below use the most common items that can be purchased at any radio store. Assembly does not require special equipment - all the necessary tools are widely available. Despite this, with a careful approach, the devices work for a long time and are not much inferior to commercial samples.

Necessary materials and tools

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

Soldering iron with a power of 25-40 watts. 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-flammable tip, because. an ordinary copper sting oxidizes rather quickly, and it has to be cleaned.
Flux for soldering (rosin, glycerin, FKET, etc.). It is desirable to use a neutral flux - unlike active fluxes (orthophosphoric and hydrochloric acids, zinc chloride, etc.), it does not oxidize 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 inhaled during soldering, but have a higher melting point with less fluidity and a tendency to degrade the weld over time.
Small pliers for bending the leads.
Nippers or side cutters for biting the long ends of leads and wires.
Installation wires in isolation. Stranded copper wires with a cross section of 0.35 to 1 mm2 are best suited.
Multimeter for voltage control at nodal points.
Insulating tape or heat shrink tubing.
A small fiberglass breadboard. A 60x40 mm board will suffice.

Breadboard made of textolite for quick installation

Diagram of a simple driver for a 1W LED

One of the simplest circuits for powering a high-power 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.

In the role of the regulator of the current passing through the led, here is a powerful field-effect n-channel transistor VT2. Resistor R2 determines the maximum current passing through the LED, and also works as a current sensor for transistor VT1 in the feedback circuit.

The more current passes through VT2, the more voltage drops on R2, respectively, VT1 opens and lowers the voltage at the gate of VT2, thereby reducing the LED current. Thus, stabilization of the output current is achieved.

The circuit is powered from a constant voltage source of 9 - 12 V, current not less than 500 mA. The input voltage must be at least 1-2 V greater than the voltage drop across the LED.

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

Due to the small number of elements, assembly can be carried out by surface mounting:

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

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

where I is the current strength in amperes.

In this circuit, the LM317 will dissipate significant power with a 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 watts.

This scheme is more clearly discussed in the following video:

This shows how to connect a powerful LED using batteries with a voltage of about 8 V. With a voltage drop across the LED of about 6 V, the difference is small, and the microcircuit heats up slightly, so you can do without a heatsink.

Please note that with a large difference between the supply voltage and the drop on the LED, it is necessary to put the microcircuit on a heat sink.

Power driver circuit with PWM input

Below is a diagram for powering high-power LEDs:

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

Driver Features

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

Operating principle

Resistor R1 with diode D1 form a reference voltage of about 0.7 V, which is additionally regulated by a variable resistor VR1. Resistors R10 and R11 serve as current sensors for the comparator. As soon as the voltage on them exceeds the reference, the comparator will close, thus closing a pair of transistors Q1 and Q2, and those, in turn, will close the transistor Q3. However, the inductor L1 at this moment tends to resume the passage of current, so the current will flow until the voltage across R10 and R11 becomes less than the reference, and the comparator again does not open transistor Q3.

The pair 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 gate of Q3, and stabilizes its operation.

The second part of the comparator (IC1 2/2) is used for additional dimming with PWM. To do this, a 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. Maximum frequency signal at the PWM input - 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 up to 1 A. If you can't find the Schottky diode, you can use a switching diode, such as FR107, but the output power will then be slightly reduced.

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

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

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

Building and configuring the driver

Driver components are mounted on a breadboard. First, the LM393 chip is installed, then the smallest components: capacitors, resistors, diodes. Then transistors are placed, 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. Diodes can also be checked with 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. Batteries 6F22 ("crown") and others have too little capacity, so their use is not advisable when using powerful 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 “ringing” mode). Next, we apply a supply voltage to the input, and by rotating the VR1 knob we achieve the required brightness of the glow.

Item List:

Conclusion

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

ledno.ru

220V LED driver circuit

The advantages of LED paws have been discussed repeatedly. The abundance of positive feedback 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 costing the conversion of an apartment to LED lighting, the numbers are a little “strain”.

To replace an ordinary 75W lamp, there is a 15W LED bulb, and a dozen of such lamps need to be changed. With an average cost of about $ 10 per lamp, the budget is decent, and the risk of acquiring a Chinese "clone" from life cycle 2-3 years. In light of this, many are considering the possibility of self-manufacturing these devices.

The theory of powering LED lamps from 220V

Most a budget option you can assemble with your own hands from these LEDs. A dozen of these little ones cost less than a dollar, and are as bright as a 75W incandescent bulb. Putting everything together is not a problem, but you can’t connect them directly to the network - they will burn out. The heart of any LED lamp is the power driver. It depends on how long and well the light bulb will shine.

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

Network parameters significantly exceed the needs of the LED. In order for the LED to be able to work from the network, it is required to reduce the voltage amplitude, current strength and convert AC voltage networks permanently.

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

LED Light Components

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

LEDs 3.3V 1W - 12 pcs.;
ceramic capacitor 0.27uF 400-500V - 1 pc.;
resistor 500kΩ - 1MΩ 0.5 - 1W - 1 sh.t;
100V diode - 4 pcs.;
electrolytic capacitors for 330uF and 100uF 16V, 1 pc.;
voltage regulator for 12V L7812 or similar - 1 pc.

Making a 220V LED driver with your own hands

The 220 volt ice driver circuit is nothing more than impulse block nutrition.

As a homemade LED driver from a 220V network, 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 such a circuit does not have a limit on the output current. The LEDs will take their prescribed one and a half amps, but if you touch the bare wires with your hand, the current will reach ten amperes, and such a current shock is very noticeable.

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

Voltage divider on capacitance;
diode bridge;
voltage stabilization stage.

The first stage is the capacitance on the capacitor C1 with a resistor. The resistor is necessary for the self-discharge of the capacitor and does not affect the operation of the circuit itself. Its value is not particularly critical and can be from 100kΩ to 1MΩ with a power of 0.5-1W. The capacitor is necessarily not electrolytic for 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. 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.

The second stage is a diode bridge. It converts AC voltage to DC. After cutting off most of the voltage half-wave by the 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 with the circuit. Its capacity depends on the power of our load.

In the driver circuit, the supply voltage for the LEDs must not exceed 12V. As a stabilizer, you can use the common element L7812.

Assembled Circuit The 220 volt LED lamp starts working immediately, but before plugging into the network, carefully insulate all bare wires and solder points of the circuit elements.

Driver option without current stabilizer

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

The problem of 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 a ripple with an amplitude of 2-3V on the diodes. When we install a 12V regulator in the circuit, even taking into account the ripple, the amplitude of the incoming voltage will be above 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 assembled by oneself, will not be inferior in terms of pulsation to similar units of expensive factory-made lamps.

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

If you have a desire to assemble a 220 volt LED spotlight 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 light sources, you need 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.

svetodiodinfo.ru

How to choose a led driver, led driver

The most optimal way to connect to 220V, 12V is to use a current stabilizer, an LED driver. In the language of the alleged enemy, "led driver" is written. 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 for 220V
4. RGB driver for 220V
5. Assembly module
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 market, Aliexpress. The prices and range are amazing. LED driver is most often chosen due to low cost and good performance.

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

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

If the manufacturer is not specified, then he does not need to be responsible for the quality and a review about his product will not be written. 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 the 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;
medium quality up to 50.000 hours;
up to 70.000h power supply on high-quality Japanese components.

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

LED driver 220V

Modern LED drivers are constructively implemented on a PWM controller, which can very well stabilize the current.

Main parameters:

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

Cases 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 the electronics. This is especially true when filling the case with a compound.

The marking often indicates 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 LEDs 12 220 from 4 to 7 pieces of 1W. It depends on the design electrical circuit LED driver.

RGB driver 220V

Three-color RGB LEDs differ from single-color ones in that they contain crystals of different colors red, blue, green in one package. To control them, each color must be lit separately. For diode tapes, an RGB controller and a 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, we divide 50W by 3, we get about 17W.

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

remotes remote control(DU) are of 2 types. With infrared control, like a TV. With radio control, the remote control does not need to be directed to the signal receiver.

Assembly module

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

If you already have a current regulator for LEDs that is not suitable for current strength, then it can be increased or decreased. Find the PWM controller chip on the board, on which the characteristics of the led driver depend. It contains the marking by which it is necessary to find the specifications for it. The documentation will indicate a typical switching scheme. Typically, the output current is set by one or more resistors connected to the legs of the microcircuit. If you change the value of the resistors or set the variable resistance according to the information from the specifications, then you can change the current. Just do not exceed the initial power, otherwise it may fail.

Driver for LED lights

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 can be higher than for indoor use. For street lighting, this indicator becomes irrelevant.

When operating outdoors, complete tightness of the power supply is required. There are several ways to protect against moisture ingress:

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

The maximum protection level is IP68, referred to as "Waterproof LED Driver" or "waterproof electronic led driver". The Chinese do not guarantee water resistance.

In my practice, the declared 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 input and output of the cable from the case, there are samples with a hole that is not closed with sealant or in another way. Water through the cable will be able to flow into the housing and then evaporate in it. This will cause corrosion on the board and exposed parts of the 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 facilitates the connection process, you can connect a segment 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:

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

DIY led driver

The simplest driver DIY can be made in 30 minutes, even if you do not know the basics of electronics. As a voltage source, you can use a power supply from consumer electronics with a voltage of 12V to 37V. Particularly suitable is the power supply from a laptop, which has 18 - 19V and power from 50W to 90W.

You will need a minimum of details, they are all shown in the picture. A radiator for cooling a powerful LED can be borrowed from a computer. Surely somewhere at home in the pantry you have old spare parts from the system unit gathering dust. It is best suited from the processor.

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

Before making a led driver 50W with your own hands, you should look a little, for example, there is one in every diode lamp. If you have a faulty light bulb that has a fault in the diodes, 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. On the basis of PWM controllers, voltage stabilizers and current stabilizers are produced. 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 PWM parameters of the microcircuit on which it is assembled are indicated as the technical characteristics of the entire module. For example, the outdated but popular LM2596, according to specifications, holds up to 3 Amperes. But without a heatsink, it can only handle 1 amp.

A more modern version with improved efficiency is the XL4015 PWM controller rated at 5A. With a miniature cooling system, it can work up to 2.5A.

If you have very powerful ultra-bright LEDs, then you need a led driver for LED fixtures. 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 desirable that it does not work in extreme conditions, this will significantly increase its reliability and service life.

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

Brightness control

To control the brightness of the LED, you can use compact LED dimmers, which have recently appeared. If its power is not enough, then you can put a larger dimmer. Usually they work in two ranges for 12V and 24V.

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

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

led-obzor.ru

LED DRIVER

We will look at a really simple and inexpensive high power LED driver. The circuit is a constant current source, which means it keeps the brightness of the LED constant no matter what power you use. If a resistor is enough to limit the current of small super-bright LEDs, then a special circuit is needed for powers above 1 watt. In general, it is better to power the LED in this way than with 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 - PSU, batteries, etc.

Specifications of led driver:

Input voltage: 2V to 18V - Output voltage: 0.5V less than input voltage (0.5V drop per field effect transistor) - 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:

An adapter transformer 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 handy, that you can use a wide variety of power supplies and it will always shine the same way. A heatsink is not required as there is about 200 mA of current flowing. If more current is planned, you must install an LED element and transistor Q1 on a heatsink.

Choice of resistance R3

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

Power dissipation in resistor approx: 0.25 / R3

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

Functions of transistors in the circuit:

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

This circuit is so simple that it makes no sense to assemble it on a printed circuit board. Just connect the leads of the parts by surface mounting.

Forum on powering various LEDs

elwo.ru

Drivers for LED bulbs.

A small laboratory on the topic “which driver is better?” Electronic or on capacitors as a 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 the formula for calculating ballast drivers. Maybe someone is interested? I will build my review on a simple principle. First, I will consider drivers on capacitors as a ballast. Then I'll look at their electronic counterparts. Well, at the end of the comparative conclusion. And now let's get down to business. We take a standard Chinese light bulb. Here is her diagram (slightly improved). Why improved? This circuit will fit any cheap Chinese light bulb. The difference will be only 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 bulbs, the ripple coefficient is 100%. Very rarely put R4. Although the resistance R4 is simply necessary. It will be instead of a fuse, and will also soften the starting current. If it is not in the diagram, it is better to put it. The current through the LEDs determines the value of capacitance C1. Depending on what current we want to pass through the LEDs (for do-it-yourselfers), we can calculate its capacitance using formula (1).

I wrote this formula many times. I repeat. Formula (2) allows you 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 the power, we still need to know the voltage drop across the LEDs. You can measure with a voltmeter, you can just count (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 5 LEDs, then 15V, if 10 - 30V, etc.). Everything is 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 passport data, the maximum current is 150mA. Let's calculate the bulb for 100mA. There will be power reserve. According to formula (1) we get: C \u003d 3.18 * 100 / (220-30) \u003d 1.67 μF. The industry does not produce such a capacity, even the Chinese one. We take the nearest convenient one (we have 1.5 μF) and recalculate the current according to formula (2). (220-30)*1.5/3.18=90mA. 90mA*30V=2.7W. This is the wattage of the light bulb. Everything is simple. In life, of course, it will be different, but not by much. It all depends on the real voltage in the network (this is the first minus of the driver), on the exact capacity of the ballast, the real 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 negligible. You can connect a lot of LEDs in series, but the total voltage drop should not exceed half the mains voltage (110V). When this voltage is exceeded, the light bulb reacts painfully to all changes in voltage. The more it exceeds, the more painful it reacts (this is friendly advice). Moreover, beyond these limits, the formula works inaccurately. Can't calculate exactly. That's a very big plus for these drivers. The power of the light bulb can be adjusted to the desired result by selecting the C1 container (both homemade and already purchased). But then there was a second disadvantage. The circuit has no galvanic isolation from the network. If you poke anywhere on the light bulb with an indicator screwdriver, it will show the presence of a phase. It is strictly forbidden to touch with your hands (a light bulb included in the network). Such a driver has almost 100% efficiency. Losses only on diodes and two resistances. It can be made within half an hour (quickly). You don't even need to charge a fee. I ordered these capacitors: aliexpress.com/snapshot/310648391.html aliexpress.com/snapshot/310648393.html These diodes are: 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 rectifying the mains voltage.

Different light bulbs will have slightly different shapes. It all depends on the size of the filter capacity C2. The larger the capacitance, the smaller the humps, the less ripple. It is necessary to look at GOST R 54945-2012. And there it is written in black and white that ripples 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 Sanitary norms SNiP 23-05-95 "NATURAL AND ARTIFICIAL LIGHTING". Depending on the purpose of the room, the maximum allowable ripple is from 10 to 20%. Nothing in life just happens. The result of the simplicity and cheapness of light bulbs is obvious. It's time to move on to electronic drivers. Here, too, not everything is so cloudless. This is the driver I ordered. This is a link to it at the beginning of the review.

Why did you order this one? Will explain. I wanted to “collective farm” lamps on 1-3W LEDs myself. Selected for price and features. I would be satisfied with a driver for 3-4 LEDs with a current of up to 700mA. The driver must include a key transistor, which will unload the driver control chip. To reduce the RF ripple, a capacitor should be placed 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. Stabilization currents of such drivers are 300mA, 600mA and higher. Ballast drivers never dreamed of such a thing (I do not recommend more than 200mA). Let's look at the specifications 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 small (also a minus). A maximum of five LEDs can be connected in series. In parallel, 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 disadvantage of these drivers is high RF interference. Some instances hear not only FM radio, but also the reception of digital TV channels disappears during their operation. The conversion frequency is several tens of kHz. But protection, as a rule, no (from interference).

Under the transformer is something like a "screen". Should reduce interference. It is This driver that almost does not fonit. Why they glow, it becomes clear if you look at the voltage waveform on the LEDs. Without capacitors, the Christmas tree is much more serious!

At the output of the driver, there should be not only an electrolyte, but also ceramics to suppress high-frequency interference. Expressed his opinion. It usually costs one or the other. Sometimes it doesn't cost anything. It happens in cheap light bulbs. The driver is hidden inside, making a claim will be difficult. Let's see the diagram. But I'll warn you, it's introductory. I applied only the main elements that we need for creativity (to understand "what's what").

There is an error in the calculations. By the way, at low powers, the device also twists. And now let's calculate the pulsations (the theory at the beginning of the review). Let's see what our eyes see. I connect a photodiode to the oscilloscope. Two pictures combined 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 ripples with a frequency of up to 300 Hz are harmful to health. And we have about 100Hz. It's bad for the eyes.
I got 20%. It is necessary to look at Sanitary norms SNiP 23-05-95 "NATURAL AND ARTIFICIAL LIGHTING". Can be used, but not in the bedroom. And I have a corridor. You can not watch SNiP. And now let's see another option for connecting LEDs. This is a wiring diagram for an electronic driver.
Total 3 parallels of 4 LEDs. Here is what the wattmeter shows. 7.1W active power.
Let's see how much comes to the LEDs. I connected an ammeter and a voltmeter to the output of the driver.
Let's calculate the pure LED power. P \u003d 0.49A * 12.1V \u003d 5.93W. Everything that is missing, the driver took over. Now let's see what our eye sees. The light on the left is off. On the right, the light is on. The 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's harmless to the eyes.

Looked at everything, measured everything. Now I will highlight the pros and cons of these circuits: Cons of light bulbs with a capacitor as a ballast compared to electronic drivers. -During operation, it is categorically impossible to touch the elements of the circuit, they are under phase. -It is not possible to achieve high LED currents, because this requires large capacitors. And an increase in capacitance leads to large inrush currents that spoil the switches. - Large ripples luminous flux with a frequency of 100 Hz, they require large filter capacitances at the output. The advantages of light bulbs with a capacitor as a ballast compared to electronic drivers. + The scheme is very simple, does not require special skills in the manufacture. + The output voltage range is fantastic. The same driver will work with one and with forty series-connected LEDs. Electronic drivers have a much narrower output voltage range. + The low cost of such drivers, which literally consists of the cost of two capacitors and a diode bridge. + You can make your own. Most parts can be found in any shed or garage (old TVs, etc.). + You can adjust the current through the LEDs by selecting the ballast capacitance. + Indispensable as an initial LED experience, as the first step in mastering LED lighting. There is another quality that can be attributed to both pluses and minuses. When using similar circuits with illuminated 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 a duty (night) lighting. I deliberately do not write which drivers are better, each has its own niche. I posted as much as I know. He showed all the pros and cons of these schemes. The choice, as always, is yours. I just tried to help. That's all! Good luck everyone.

mysku.ru

How to choose an LED driver - types and main characteristics

What is a driver and what is its purpose?

The driver for LEDs is an electronic device, the output of which is a constant current after stabilization. In this case, it is not a voltage that is formed, but a current. Devices that stabilize the voltage are called power supplies. The output voltage is indicated on their case. 12 V power supplies are used to power LED strips, LED strips and modules.

Key Features

The electronic filling of the device is affected by many reasons:

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

Specifications

Before purchasing a converter for LEDs, you should study the characteristics of the device. These include the following options:

output power;
output voltage;
rated current.

LED driver connection diagram

P(led) is the power of one LED element;

n is the number of LED elements.

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

When performing the calculation, the color factor of the consumer should be taken into account, as it affects the voltage drop. Different colors will have different meanings.

Best before date

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

How to choose a driver?

There are many types of drivers used for LED lighting. Most of the presented products are made in China and do not have the required quality, but stand out at the same time with a low price range. If you need a good driver, it is better not to chase cheap Chinese-made ones, since their characteristics do not always match the declared ones, and they rarely come with a guarantee. There may be a defect on the microcircuit or a quick failure of the device, in which case it will not be possible to exchange for a better product or return the funds.

Types of drivers

Devices that power LEDs can be conditionally divided into:

impulse;
linear.

From the above, we can conclude that the power supply for LEDs should be chosen very carefully. An example is a fluorescent lamp, which is supplied with a current exceeding the norm by 20%. There will be practically 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 turn on medium power LED diodes to the most popular ratings of 5V, 12 volts, 220V. Then they can be used in the manufacture of color music devices, signal level indicators, smooth switching on and off. I've been going to make a smooth artificial dawn for a long time in order to follow the 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 considered from complex to simple, from expensive to cheap.

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

Schema types

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

constant current LED driver;
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. A resistor (resistance) is not required.

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

The calculator takes into account 4 parameters:

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

If you are using 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 an adjustment of the set resistance will be required. To check how large the spread of parameters is, you need to turn everything on sequentially. We connect the power of the LEDs and then lower the voltage until they barely glow. If the characteristics differ greatly, then part of the LED will work brightly, part dimly.

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

Designation on the diagram

For designation on the diagram, the above two pictograms are used. Two parallel arrows indicate that it shines very strongly, the number of bunnies in the 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 is of two types:

simple on the 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 voltage of 220V is reduced by a high-voltage capacitor, which then straightens and stabilizes a little. 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 do not notice it at all. It is also difficult to calculate the circuit due to the spread of the characteristics of electronic components.

A complete circuit using dedicated chips provides better stability at the output of the driver. If the driver copes well with the load, then the ripple factor will be no higher than 10%, and ideally 0%. In order not to make a driver with your own hands, 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 corrected with a minimum of effort. Find specifications to 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 more resistance to them or removing one of them, you can get the required current strength. The only thing you can not exceed the specified power.

DC voltage connection

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

The simplest low voltage driver

The simplest current regulator circuit for LEDs consists of a linear LM317 chip 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 offset by the maximum ease of manufacture.

Input up to 37V, up to 1.5 Amps for the case indicated in the picture.

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

Drivers powered from 5V to 30V

If you have a suitable power source from any household appliances, then it is better to use a low-voltage driver to turn it on. They are up and down. Boosting even from 1.5V will make 5V to make the LED circuit work. Stepping down from 10V-30V will make it lower, for example 15V.

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

The real power of such a stabilizer will be lower than indicated by the Chinese. At the parameters of the module, they write the characteristics of the microcircuit and not the entire structure. If there is a large radiator, then such a module will pull 70% - 80% of the promised one. If there is no radiator, then 25% - 35%.

Models based on the LM2596 are especially popular, 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.

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

Turn on 1 diode

The most commonly used are 12 volts, 220 volts and 5V. Thus, low-power LED lighting of 220V wall switches is made. In factory standard switches, a neon lamp is most often placed.

Parallel connection

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

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

Serial connection

Serial connection when powered by 220V is used in filament diodes and LED strips for 220 volts. In a long chain of 60-70 LEDs, 3V drops on each, which allows you to connect directly to high voltage. Additionally, only a current rectifier is used to obtain plus and minus.

Such a connection is used in any lighting engineering:

LED lamps for home;
led lamps;
christmas garlands for 220V;
led strip 220.

Home lamps usually use up to 20 LEDs connected in series, the voltage on them is about 60V. Maximum amount used in Chinese corn bulbs, 30 to 120 pieces LED. 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 daisy chain, and they don't always have a ground connection. 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 in one housing. If 3 crystals (red, green, blue) are turned on at the same time, we will get white light.

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

Turn on COB diodes

The connection schemes 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 serial circuit of several crystals is included.

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

Connecting SMD5050 to 3 crystals

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

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

When 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 diagram becomes more complicated. Therefore, it is not used in LED strips and lamps.

LED Strip 12V SMD5630

A good 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, you can cut it only in the indicated places between these sections.

LED strip RGB 12V SMD5050

The RGB tape uses three colors, each is controlled separately, a resistor is placed for each color. You can cut only at the indicated place so that each section has 3 SMD5050 and it can connect to 12 volts.

led-obzor.ru Wiring diagrams for sockets and switches

LED driver circuits

Just about the complex. Programs. Iron. Internet. Windows

Calculation of the driver for the LED lamp. Drivers for LEDs: types, characteristics and criteria for selecting devices. LEDs for LED drivers

Principle of operation

Main characteristics

Types of LED Drivers

Linear stabilizer

Pulse stabilization

What is the difference between LED driver and led strip power supply

How to choose

What is a driver and what is its purpose?

Key Features

Specifications

Best before date

How to choose a driver?

Types of drivers

What is the purpose of drivers?

Where are LED drivers used?

How does the driver work?

What are the main characteristics LED drivers?

How to connect LEDs correctly?

Linear and pulse drivers. What are their operating principles?

Need a 220V LED driver?

Should I buy Chinese drivers?

What is the lifespan of a led driver?

Power supply circuit for LEDs based on a capacitor divider

Driver circuit on CPC9909

General information

Pin assignment

Scheme and its principle of operation

Calculation of external elements

Frequency setting resistor

current sensor

Throttle

Power filter

Rectifier

Selecting the Rest of the Schematic Elements

Other options for enabling CPC9909

Soft start and analog dimming

Pulse dimming

Homemade driver for LEDs from a 220V network. Schemes of ice drivers

Do-it-yourself LED driver: simple diagrams with descriptions

How to make an LED driver

Necessary materials and tools

Diagram of a simple driver for a 1W LED

Power driver circuit with PWM input

Driver Features

Operating principle

Building and configuring the driver

Conclusion

220V LED driver circuit

The theory of powering LED lamps from 220V

LED Light Components

Making a 220V LED driver with your own hands

Driver option without current stabilizer

How to choose a led driver, led driver

Features of Chinese

Life time

LED driver 220V

RGB driver 220V

Assembly module

Driver for LED lights

Power supply for led strip

DIY led driver

Low voltage

Brightness control

LED DRIVER

Details on the diagram:

Choice of resistance R3

Functions of transistors in the circuit:

Drivers for LED bulbs.

How to choose an LED driver - types and main characteristics

What is a driver and what is its purpose?

Key Features

Specifications

Best before date

How to choose a driver?

Types of drivers

Schemes for connecting LEDs to 220V and 12V

Schema types

Designation on the diagram