LED Light and LED driver power
LED driver power is included in the national 3C compulsory certification. The problem of power supply has become an important factor affecting the popularization and application of LED lights.
1. the power requirements of LED particles
The LED light is an integral light-emitting structure, including LED light source and power supply. The LED light source is composed of a certain number of high-power LED particles mixed (serially followed by parallel) into a whole light-emitting chip. A single LED is actually a diode. When a certain forward voltage is applied across the diode to excite the P-N junction to conduct current, the LED can emit light. The nominal voltage of a single LED is 3.4V ± 0.2V (the actual working voltage is about 2.8 ~ 3.8V). Working current is related to power and brightness. LEDs with different powers have different currents. Generally speaking, the greater the power, the higher the current, the more light is emitted.
2. LED drive power
When the power supply line is 220V AC, 3 steps of voltage reduction, rectification, and current stabilization must be performed to provide a stable low-voltage DC power supply for LED lights. 1st, the 220V AC is stepped down to 48V low voltage AC, and then the low voltage AC is converted into low voltage DC by bridge rectification, and then converted into a constant current source by a high-efficiency switching regulator to provide a constant current. Choosing a combination of fewer strings and more parallels can reduce the chip failure rate, and the voltage requirements of existing LED lights are mostly 48V. According to the actual voltage and current of the LED lights, select the appropriate driving power supply.
3. power failure analysis
Since the LED particles and the power supply are distributed in the narrow space of the light, the power supply needs to be sealed to prevent moisture and waterproof. But it will affect the heat dissipation, LED power supply working at high temperature will reduce the long-life. At the same time, after the encapsulation, the damaged parts can only be replaced as a whole, which is not only difficult to repair but also expensive.
4. DC power supply mode
Transfer the scattered driving power from the light to the ground, and handle it in the transformer or switch box on the ground. The DC transformer concentrated on the ground not only has high conversion efficiency and controllable temperature, but also facilitates maintenance. Once the LED street light realizes the low-voltage DC power supply mode, it will also provide protection for the safety of street lights and provide conditions for charging electric vehicles in the future.
5. Technical approach
The driving power of the traditional LED street light can be removed, and the low-voltage DC power supply can be directly provided by the LED light distribution control. The structural design of the LED street lamp can be more simplified, and the reliability is increased accordingly.