Basic composition of switching power supply

The switching power supply consists of four parts: main circuit, control circuit, detection circuit and auxiliary power supply.

1. Main circuit impact current limiting: limiting the input current impulse at the instant of switching on the power supply. Input filter: Its function is to filter the clutter existing in the power grid and to impede the clutter generated by the unit to feed back to the power grid. Rectification and filtering: the AC power supply of the grid is directly rectified to a smooth DC power. Inverter: converting rectified DC to high frequency AC, which is the core of high frequency switching power supply. Output rectifier and filter: provide reliable and stable DC power supply according to load needs.

2. On the one hand, the control circuit sampled from the output terminal, compared with the set value, and then controlled the inverter to change its pulse width or pulse frequency, so as to stabilize the output. On the other hand, according to the data provided by the test circuit, after the protection circuit identification, the control circuit provides a variety of protection measures for the power supply.

3, the detection circuit provides various parameters and various instrument data in operation in the protection circuit.

4. Auxiliary power supply realizes the software (remote) start of power supply, and supplies power for protection circuit and control circuit (PWM chip).