A dual-transistor flyback topology switching power supply circuit driven by transformer leakage inductance

Abstract

The invention provides a dual-transistor flyback topology switching power supply circuit driven by transformer leakage inductance, which includes a drive signal input end, an isolation driving chip, afirst capacitor, a second capacitor, a first resistor, a second resistor, a third resistor, a fourth resistor, a first field effect transistor, a second field effect transistor, a first diode, a second diode, a first inductor, a flyback transformer, a third diode, a fifth resistor, a driving supply voltage input terminal, and a switching power supply voltage input terminal. As that circuit of theinvention is simple, the reliability is good, the drive transformer is not need, and the leakage inductance of the flyback transformer is fully utilized, the power density of the switch power supplycan be effectively improved.

Description

technical field [0001] The invention relates to a switching power supply, in particular to a dual-tube flyback topology switching power supply circuit driven by transformer leakage inductance. Background technique [0002] Switching power supplies are an integral part of electronic equipment. With the development of power electronics technology, switching power supply is developing in the direction of high frequency, high power density and high reliability. However, the voltage levels required in electronic products are usually different, and electrical isolation is usually required between products. Because the flyback circuit can simply add secondary windings to achieve multi-channel isolated output, in small and medium power supply occasions, it can be obtained widely used. But for the single-tube flyback converter, due to the existence of transformer leakage inductance, when the switch tube is turned off, a high voltage stress peak will be generated on the switch tube;...

AI Technical Summary

Problems solved by technology

However, since the two switching tubes of the dual-tube flyback circuit are switched to the conduction state synchronously, the existing technology uses the driving transformer to complete the driving. Due to the existence of the DC blocking capacitor, the secondary side of the driving transformer will have a negative voltage, which is easily damaged in severe cases. turning tube

At the same time, the existing drive technology often needs to increase the push-pull circuit to increase the drive power.

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