Basic composition of switching power supply

The switching power supply is composed of four major parts: the main circuit, the control circuit, the detection circuit and the auxiliary power supply.
1. Main circuit
Inrush current limiter: Limit the inrush current on the input side when the power is turned on.
Input filter: Its function is to filter the clutter existing in the grid and prevent the clutter generated by the machine from being fed back to the grid.
Rectification and filtering: rectify the AC power of the grid directly into a smoother DC.
Inverter: Convert the rectified direct current into high-frequency alternating current, which is the core part of the high-frequency switching power supply.
Output rectification and filtering: Provide stable and reliable DC power according to the needs of the load.
2. Control circuit
On the one hand, take samples from the output end, compare with the set value, and then control the inverter to change its pulse width or frequency to stabilize the output; The control circuit performs various protection measures for the power supply.
3. Detection circuit
Provides various parameters and various instrument data in operation in the protection circuit.
4. Auxiliary power supply
Realize the software (remote) startup of the power supply, and supply power for the protection circuit and the control circuit (chips such as PWM).