Switching power supply is a type of power supply that utilizes modern power electronics technology to control the time ratio of switch on and off, and maintain a stable output voltage. Switching power supply is generally composed of pulse width modulation (PWM) control IC and MOSFET. With the prospect and advancement of power electronics technology, switching power supply technology is also constantly improving. At present, switching power supply is widely used in almost all electronic facilities due to its small size, lightweight, and high efficiency, and is an indispensable power supply method for the rapid development of the electronic information industry today.
With the rapid development of power electronic technology, the relationship between power electronic facilities and people's work and life is becoming increasingly close. Electronic facilities cannot do without reliable power sources. In the 1980s, computer power supply * * achieved switch mode power supply, taking the lead in completing the power supply replacement of computers. In the 1990s, switch mode power supply has entered various fields of electronic and electrical facilities, such as program-controlled switches, communication, and electronic testing facility power supply Switching power supplies have been widely used in control facilities, such as power supply, which has promoted the rapid prospects of switching power supply technology.
Compared to linear power supplies, the cost of both increases with the increase of output power, but their growth rates vary. The cost of linear power supply is actually higher than that of switching power supply at a certain output power point. With the prospect of power electronics technology and the continuous improvement of switching power supply technology, this cost reversal point is increasingly moving towards the low output power end, providing a wide range of prospects for switching power supply.
High frequency switching power supply is the direction of its future. High frequency makes switching power supply miniaturized and enters a wider range of applications, especially in the field of high-tech technology, promoting the miniaturization and portability of high-tech products. In addition, the prospects and applications of switching power supply are of great significance in security monitoring, energy conservation, resource conservation, and environmental protection.

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.