1) Main circuit: The main circuit from the AC grid input to the DC output. It mainly includes input filter, rectification and filtering, inverter, output rectification and filtering.
(1) Input filter: Its function is to filter the clutter existing in the power grid, and also prevent the clutter generated by the machine from being fed back to the public power grid.
(2) Rectification and filtering: The AC power supply of the grid is directly rectified into a smoother DC power for the next level transformation.
(3) Inverter: Convert the rectified direct current into high-frequency alternating current, which is the core part of the high-frequency switching power supply. The higher the frequency, the smaller the ratio of volume, weight and output power.
(4) Output rectification and filtering: according to the needs of the load, provide a stable and reliable DC power supply.
2) Control circuit: On the one hand, take samples from the output end, compare it with the set standard, and then control the inverter to change its frequency or pulse width to achieve stable output; on the other hand, according to the data provided by the test circuit, the The protection circuit is identified, and the control circuit is provided to carry out various protection measures for the whole machine. Including output sampling circuit, feedback circuit and pulse width modulator.
3) Detection and protection circuit: The detection circuit includes overcurrent detection, overvoltage detection, undervoltage detection, overheat detection, etc.; the protection circuit can be divided into overcurrent protection, overvoltage protection, undervoltage protection, clamp protection, overheat protection, Automatic restart, soft start, slow start and other types.
4) Other circuits: such as sawtooth wave generator, bias circuit, optocoupler, etc.
