Views: 0 Author: Site Editor Publish Time: 2021-05-21 Origin: Site
The key to high-quality LED lighting products is heat dissipation, driving power and light sources, and heat dissipation is particularly important. The heat dissipation effect directly affects the service life of the lighting product, and the service life of the driving power supply itself and the stability of the output current and voltage will all affect the lighting product.
LED drive power supply is a standard product of LED, and the quality of power supply on the market is uneven. The following content provides some relevant knowledge about LED driver power supply.
1. What is LED drive power
The LED driving power supply converts the power supply into a specific voltage and current to drive the LED light-emitting voltage converter.
2.Do LED lights work without power supply?
The answer is NO, Any kind of led light bar will needs a power supply to be drive.
3. Features of LED driver/ power supply?
(1) High reliability, especially like the driving power of LED street lamps, installed at high altitude, it is inconvenient to maintain, and the maintenance cost is also high.
(2) High-efficiency LED is an energy-saving product, and the efficiency of the driving power supply should be high. It is very important for the heat dissipation of the junction of the power supply installed in the luminaire. The efficiency of the power supply is high, its power consumption is small, and the heat generated in the lamp is small, which reduces the temperature rise of the lamp. It is beneficial to delay the light decay of LED.
(3) High power factor
The power factor is the requirement of the power grid on the load. Generally, there are no mandatory indicators for electrical appliances below 70 watts. Although the power factor of a single consumer with low power is lower, it has little effect on the power grid, but the large amount of lighting used at night and too concentrated similar loads will cause serious pollution to the power grid. For LED driving power supplies of 30 watts to 40 watts, it is said that in the near future, there may be certain index requirements for power factors.
(4) Drive mode
Currently, there are two types: one constant voltage source for multiple constant current sources, and each constant current source individually supplies power to each LED. In this way, the combination is flexible, and the failure of one LED will not affect the work of other LEDs, but the cost will be slightly higher. The other is direct constant current power supply, which is the driving method adopted by "Zhongke Huibao", LED series or parallel operation. Its advantage is that the cost is a bit lower, but the flexibility is poor, and it must solve the problem of a certain LED failure without affecting the operation of other LEDs. These two forms coexist for a period of time. Multi-channel constant current output power supply mode will be better in terms of cost and performance. Maybe it will be the mainstream direction in the future.
(5) Surge protection
The ability of LED to resist surge is relatively poor, especially the ability to resist reverse voltage. It is also important to strengthen protection in this area. Some LED lights are installed outdoors, such as LED street lights. Due to the initiation of the grid load and the induction of lightning strikes, various surges will be invaded from the grid system, and some surges will cause damage to the LED. Therefore, it is analyzed that the drive power of "Zhongke Huibao" should have certain deficiencies in surge protection. As for the frequent replacement of power supplies and lamps, the LED drive power must have the ability to suppress the intrusion of surges and protect the LED from damage.
(6) Protection function
In addition to the conventional protection functions of the power supply, it is best to add negative feedback of the LED temperature in the constant current output to prevent the LED temperature from being too high; it must meet the requirements of safety regulations and electromagnetic compatibility.
4. Classified by driving mode
(1) The output current of the constant current type constant current drive circuit is constant, but the output DC voltage varies within a certain range with the size of the load resistance. The load resistance is small, the output voltage is low, and the load resistance is The larger the value, the higher the output voltage; the constant current circuit is not afraid of the load short circuit, but it is strictly forbidden to open the load completely; the constant current drive circuit to drive the LED is more ideal, but the price is relatively higher; pay attention to the maximum withstand current and The voltage value, which limits the number of LEDs used.
(2) Voltage-stabilized type: After the various parameters in the voltage-stabilizing circuit are determined, the output voltage is fixed, but the output current changes with the increase or decrease of the load; the voltage-stabilizing circuit is not afraid of load opening, but it is strictly prohibited to load completely Short circuit; LEDs are driven by a voltage-stabilizing drive circuit, and each string needs to be added with a suitable resistance to make each string of LEDs display an average brightness; the brightness will be affected by the voltage change from the rectification.
5. The advantages and disadvantages of the overall constant current and the channel-by-channel constant current working mode
Compared with the overall constant current, although the channel-by-channel constant current has more disadvantages, the cost is also higher. But it can really protect the LED and extend the life of the LED, so the constant current is the future trend.
6. Lack of LED power supply
The technical staff of the company that produces LED lighting and related products do not know enough about switching power supplies, and the power supply made can work normally, but some key assessments and electromagnetic compatibility considerations are not enough, and there are still hidden dangers; most LED power supplies Manufacturers are all transitioning from ordinary switching power supplies to LED power supplies, and they are not sufficiently aware of the characteristics and use of LEDs; there are almost no standards for LEDs, and most of them refer to the standards of switching power supplies and electronic rectifiers; now most of the LEDs The power supply is not uniform, so most of the quantity is relatively small. The purchase quantity is small, the price is high, and the component suppliers are not very cooperative; the stability of the LED power supply: wide voltage input, high and low temperature operation, over-temperature, over-voltage protection and other problems are not solved one by one.
The first is the overall life of the drive circuit, especially the key components such as: the life of the capacitor at high temperatures directly affects the life of the power supply; the second is that the LED driver should challenge higher conversion efficiency, especially when driving high-power LEDs. Because all the power that is not used as light output is dissipated as heat, the power conversion efficiency is too low, which affects the performance of the LED energy-saving effect; at present, the cost of the constant current drive power supply is accounted for in the application of low power (1-5W) The proportion of light source is close to 1/3, which is close to the cost of the light source, which affects the market promotion to a certain extent.