Low noise switching power supply principle circuit diagram

The circuit is as shown in the figure. This circuit can obtain greater output power by only changing some components. The circuits R1, L1, D1, C1 to C7 on the left in the figure are conventional common-mode filtering and rectification circuits, which obtain a DC voltage of about 300 V for use by the DC-DC conversion circuit; the circuits L5, C11, etc. on the far right are ordinary LC Filter circuit; IC 2, D8, R9, and R10 form a voltage feedback circuit, forming 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 handle this part of the circuit.

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