Low noise switching power supply principle circuit diagram

The circuit is shown in the figure. This circuit can obtain a higher output power by simply changing some components. The circuit R1, L1, D1, C1 to C7 on the left side of the figure is a conventional common-mode filter and rectifier circuit, which obtains a DC voltage of about 300 V for use in the DC-DC conversion circuit; the circuit L5, C11, etc. on the far right are ordinary LC filter circuits; IC2, D8, R9, R10 form a voltage feedback circuit to form a closed-loop structure to stabilize the power supply output voltage; the middle part is the DC-DC converter, and the key to reducing noise is to properly process this part of the circuit.