Voltage reduction circuits of high power switching power supply

The invention relates to voltage reduction circuits of a high power switching power supply. The existing voltage reduction circuits are easy to generate large current pulse under the condition of overlarge pressure difference, thus destroying the stability of the system. The invention comprises a pre-stage current filter circuit, a primary voltage reduction circuit, a diode (D), a secondary voltage reduction circuit and two feedback circuits, wherein one end of the pre-stage current filter circuit is connected with the anode of the direct current input voltage; one end of the primary voltage reduction circuit is connected with the other end of the pre-stage current filter circuit after being connected with one feedback circuit in parallel and the other end thereof is connected with the anode of the diode after being connected with the feedback circuit in parallel; one end of the secondary voltage reduction circuit is connected with the cathode of the diode after being connected with the other feedback circuit in parallel and the other end thereof serves as the voltage output end; and the two feedback circuits adopt exactly the same circuit structure. The voltage reduction circuits adopt continuous two-stage voltage reduction, thus breaking through the barrier of overlarge pressure difference and reducing the high direct current voltage stably, efficiently, accurately and safely.