LED lamps are gradually replacing other lighting products from the market. These are economical, durable devices that can create a luminous flux of different colors. They differ in a more complex device than incandescent lamps. They have a power supply in the design. It can be different. How the power supply for LED lamps is arranged, which kind to choose, will be discussed later.
LED power supply
To repair the power supply of an LED lamp, you need to understand the principle of operation of such an element of the system.
The power source of such a lighting device must meet a number of requirements. The main ones are as follows:
- energy efficiency
- reliability;
- electromagnetic compatibility;
- security.
Only by providing the LEDs with a power source with the listed qualities, it is possible to achieve the correct operation of the device and extend its life.
It is worth noting that the duration of operation of the presented lighting devices is at least 50 thousand hours. Accordingly, the power supply must work at least as much time. It should be remembered that the main reason why LED lamps displace all other types of lighting devices is energy-saving technology. Therefore, the power supply must also have high efficiency. Otherwise, due to the power supply, energy savings will be negligible.
It is also worth noting that the presented part is the only source of electromagnetic type interference. Therefore, the compatibility of the LED lamp with the mains depends on the power supply.
The only element in the presented lighting device, which is supplied with voltage from the household network, is the power supply unit of LED lamps. 220V in this element of the system is transformed, decreasing to 12 V at the output. For this reason, the electrical safety of the device is completely dependent on this device.
In addition, the power supply affects the lighting characteristics of the lamp, on what current will flow through the LED. If it pulsates, then the luminous flux will be of poor quality, poorly affect vision.
Lamp and driver device
The power supply for a 12V LED lamp is the most common variety. Depending on the characteristics of the lamp, it can give an output of 5, 12, 24, 48 V. In this case, the current from AC is converted to DC. This is a prerequisite for the correct operation of the system.
Before you consider the device of this element of the lamp, you need to pay attention to its place in the design. This will allow repair if necessary. LED type lamps have the same device. If you remove the case, you can see the driver inside. This is a printed circuit board on which the radio elements are soldered.
The base of the presented devices most often has a size of G4. The power supply for LED lamps follows immediately after it. Electricity is supplied to the contacts of the cartridge, transmitted to the conclusions of the cap. Two wires are connected to it, through which voltage is supplied to the driver (power supply). Here, the current is transformed to the given parameters. It goes to the board to which the LEDs are soldered.
A driver is an electronic unit that is a current generator. It, in turn, also has several main components. The voltage from the household network first falls on the filter. It eliminates electromagnetic interference. Next, the current flows to the rectifier. Here he becomes permanent. The next stage of the power supply is designed to correct the power factor. The last stage that an electric current passes in this device is a pulsed current stabilizer. LEDs are connected to its output.
Such a device has any LED lamp. If you need to assemble power supplies for LED emergency or main purpose lamps, adhere to the indicated scheme.
LED Power Features
The power supply of LED lamps for 220V has some features. This must be taken into account when planning to make or repair this device. The LED has a nonlinear dependence of voltage and current. This feature is possessed by all lighting devices of the presented type.
So, with an increase in the nominal voltage, the current on the LED increases sharply. This may cause a malfunction. Therefore, in inexpensive lamps (often of Chinese origin), a limiting resistor is installed in series with the LED. If a voltage surge occurs, it will not allow the current to increase. But at the same time, the power will drop on the resistor. The efficiency of an inexpensive lamp is therefore reduced.
The power supply provides normal voltage to power the LEDs. It is this device that is most often included in the circuit of the lamps of the type presented. The power supply for a 12V LED lamp or with a different output voltage value is called a driver. This is the marketing designation of such devices. A constant voltage source for LEDs that operate on 12 V is commonly called a power supply. If the device also stabilizes the input current, then this is the driver. We can say that this is a type of power supply, which is installed in high-quality lamps.
Varieties of Power Supplies
Having considered the device of the power supply of the LED lamp, you need to pay attention to the varieties of such devices. They can be transformer or pulse. They differ in the device and the principle of operation.
So, a transformer is used at the base of the transformer block. This is a down type device. The voltage for any LED-type lamp needs to be reduced from 220 V to 12 V or another desired value. Only then is the current supplied to the rectifier. Any LED lamp works from a direct current.
The advantage of transformer varieties of devices is the simplicity of their design. They are able to withstand the load in idle mode and are decoupled from the household network. However, the presented variety of the block also has disadvantages. The main ones are low efficiency (50-70%), as well as the sensitivity of the system to overloads.
The switching power supply for LED lamps also has a transformer in its design. But in this case, it works at higher frequencies. Therefore, its weight and size are several times smaller. A conventional transformer power supply operates at a frequency of 50 Hz. It is much larger. The efficiency of the pulse device is 70-80%.
In pulsed varieties of the device, there is also isolation from the network. This device is also sensitive to overloads, but it may cease to function even when idling. Such a device may ignite under significant overload.
Driver Features
When choosing a power supply for a 220 V LED lamp, you need to pay attention to the features of devices that are commonly called drivers. These are impulse varieties of power supplies. They stabilize the outgoing voltage that is supplied to the LEDs. Such devices are single and double stage. The second option is preferable. Two-stage drivers are installed in the vast majority of circuits. They have a special principle of action.
So, the first stage is a power factor corrector. The second element of the system is the output voltage stabilizer. The corrector block is necessary, since the driver is a pulsed device type. It must comply with the requirements specified in GOST, which relate to the suppression of harmonics of the incoming voltage.
The two-stage driver complies with the standards and requirements that are put forward to the quality of the luminous flux. Such a power supply for 12 volt LED lamps is capable of providing a ripple of 1%. This is a good indicator. Such lighting will not adversely affect a person’s vision and nervous system. In this case, the power factor of the two-stage device is 0.92-0.96.
It is worth noting that the presented driver circuit is quite expensive. Therefore, manufacturers of cheap lamps install a single-stage driver circuit. Such systems are more suitable for creating lighting in the pantry, utility room, basement or porch. In an apartment or house, you need to apply two-stage schemes.
A few more words about the drivers
It is worth noting that, unlike the power supply unit, the driver does not have such a characteristic as “outgoing voltage”. For this device, only indicators such as output current and power are characteristic. This means that the presented type of power supply will not produce a current with a higher value than was calculated by the manufacturer.
There are drivers designed for a certain number of LEDs (for example, 5 pcs.). In this case, you can connect less lighting elements, but no more.
Other types of presented elements of the electrical circuit of the lamp can work with any number of LEDs. However, their total power should not exceed the value set by the manufacturer. It is worth noting that universal drivers will have less efficiency. This is due to the specifics of the pulse circuit.
Varieties of drivers
On sale are several types of power supplies for LED lamps. The main ones are as follows:
- capacitor circuit;
- resistor;
- driver with low voltage input;
- Chip HV9910;
- network driver;
- microcircuit LM317.
The choice depends on the characteristics of the device, its operation parameters.
Expert Advice
When choosing a power supply for LED lamps, you need to know how their existing types differ. Specialists in the field of lighting give some advice. Wizards claim that when used in a driver circuit, the LEDs can operate at full power. This is explained by the absence of the need to lower the voltage. In this case, the LEDs will not fail due to increased power.
If the power is supplied using the power supply, part of the voltage will be consumed due to the heating of the resistors. The latter are responsible for limiting the voltage during a jump in the current indicators. Therefore, by powering the system using the driver, you can significantly extend the life of the LEDs. The current in this case will never exceed the permissible value.
It is worth considering that the driver is a device that is designed for current with certain characteristics, given power. Therefore, in order to assemble or repair the power supply from an LED lamp with your own hands, you need to select it in accordance with the number and type of LEDs. Their power should correspond to the selected power device.
A conventional power supply can be used for any electrical device, and the driver is specifically designed for LEDs. This must be taken into account when buying a device. There are a number of factors that influence the choice of type of power supply device.
What type of device to choose?
The power supply for LED lamps, as well as drivers, must be selected in accordance with the particular operation of the device. Experienced masters give some tips on what kind of power supply device is best to purchase in a particular case.
The driver is preferable to use in the circuit with LEDs, if the circuit does not provide resistors. This happens if you need to power individual diodes. The presented variety of devices is also used if it is not necessary to periodically disconnect part of the LEDs from the driver.
Also in specialized stores it is easier to choose an input voltage stabilizer. The driver is selected in accordance with the number of LEDs and their power. A qualified sales consultant should help. Therefore, when purchasing the necessary equipment in a store, it is better to opt for a driver.
If the circuit includes LEDs with built-in resistors, it is better to purchase a power supply. This decision will be correct in cases where it is sometimes necessary to turn off part of the LEDs.
Selection tips
Experts advise to approach the choice of power supply for LED lamps in a comprehensive manner. Turning to a specialized store, you must first determine the type of power source. Having decided whether you need a driver or a power supply, you can proceed to the next step. The total power of the LEDs is determined. The power supply must not only correspond to this value, but also have a margin of about 20%. To calculate the power, you need to look into the lamp data sheet.
The driver must match the rated power and current of the LEDs. A power source that outputs 12 volts is not suitable for a 48 volt light fixture.
Next, you need to pay attention to the rate of protection of the case from external weather conditions. You need to decide for what purpose you need a lamp. If it will be mounted outdoors, in a humid or dusty room, the protection class must be high. This indicator is indicated by the letters IP in the marking. For home use, you can choose the power supply with the lowest protection class. Devices of the IP65 type are designed for outdoor installation or indoors in a bathtub, bathhouse or shower. Such a power supply is not afraid of a direct hit of a jet of water on the case. The cost of protected devices is an order of magnitude higher.