In addition to meeting safety requirements, the LED driver circuit should also have two basic functions:
One is to maintain constant current characteristics as much as possible, especially when the power supply voltage changes by ± 15%, the output current should still be able to fluctuate within the range of ± 10%. The main reasons are: 1. To avoid driving current exceeding the rated value, which affects its reliability 2. Obtain the expected brightness requirements and ensure the consistency of brightness and chromaticity of each LED.
The second is that the driving circuit should maintain a low self power consumption in order to maintain a high level of LED system efficiency.
LED driver power supply converts the power supply into a specific voltage and current to drive the voltage converter of LED lighting. Generally, the input of LED driver power supply includes high-voltage power frequency AC (i.e. mains power), low-voltage DC, high-voltage DC, low-voltage high-frequency AC (such as the output of electronic transformers), etc. The output of LED driver power is mostly a constant current source that can change the voltage with the change of LED forward voltage drop value. The core components of LED power supply include switch controllers, inductors, MOSFETs, feedback resistors, input filter devices, output filter devices, and so on. According to the requirements of different occasions, there should also be input overvoltage protection circuit, input undervoltage protection circuit, LED open circuit protection, overcurrent protection circuit, etc.