Circuit for reducing voltage stress of switching power supply MOS tube based on RCD

Abstract

Provided is a circuit for reducing voltage stress of a switching power supply MOS tube based on an RCD. A power output end is connected to one end of a primary winding of a transformer T1, the primary winding of the transformer T1 is connected to an RCD circuit composed of a resistor R1, a capacitor C1 and a diode D2, the resistor R1 is connected with the capacitor C1 in series and then is connected with the diode D2 in parallel, the negative electrode of the diode D2 is connected to the power output end, the positive electrode of the diode D2 is connected to the other end of the primary winding of the transformer T1 and the drain electrode of a MOS tube U1, the grid electrode of the MOS tube U1 is connected into a control circuit, the source electrode of the MOS tube U1 is connected to the ground, one end of the secondary winding of the transformer T1 is connected to the positive electrode of a power diode D1, the negative pole of the power diode D1 is connected to the control circuit to achieve detection of input and output voltages, the negative pole of the power diode is connected to one end of a capacitor Cout at the same time, and the other end of the capacitor Cout and the other end of the secondary winding of the transformer T1 are both grounded. Reverse voltage resistance capacity of the diodes can be lowered effectively, and the reliability of the diodes is guaranteed.

Description

technical field [0001] The invention relates to the technical field of switching power supplies, in particular to an RCD-based circuit for reducing the voltage stress of MOS tubes of switching power supplies. Background technique [0002] For a typical switching power supply circuit, at the moment when the diode is turned off and on, due to the parasitic capacitance, a high voltage spike will be generated at both ends of the diode, which will easily cause the diode to be broken down and cause the circuit to fail. Contents of the invention [0003] In order to overcome the deficiencies of the above-mentioned prior art, the purpose of the present invention is to provide a circuit based on RCD to reduce the voltage stress of the MOS tube of the switching power supply, and the absorbing circuit is formed by the RCD to reduce the voltage stress of the diode. [0004] In order to achieve the above object, the technical scheme adopted in the present invention is: [0005] An RCD...

AI Technical Summary

Problems solved by technology

[0002] For a typical switching power supply circuit, at the moment when the diode is turned off and on, due to the relationship between the parasitic capacitance, a high voltage spike will be generated at both ends of the diode, which will easily cause the diode to be broken down and cause the circuit to fail.

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