Active clamp synchronous rectification forward converter

Abstract

The invention discloses an active clamp synchronous rectification forward converter, and belongs to the technical field of electronics. The converter comprises a direct current input power supply, an input capacitor, a main transformer T1, a synchronous rectifier circuit, a filter circuit, a voltage sampling circuit, an optical coupling feedback circuit, a PWM control circuit and an active clamp circuit; the synchronous rectifier circuit consists of a rectifier tube and a driving circuit thereof, and a freewheeling tube and a driving circuit thereof, wherein the driving voltage of the rectifying tube is generated by a secondary auxiliary winding of the main transformer, and has the same phase as that of a first switching tube of the active clamp circuit; and the driving voltage of the freewheeling tube is generated by coupling the driving voltage of a second switching tube in the active clamp circuit, so the driving voltage has the same phase as that of the second switching tube in the active clamp circuit. The synchronous rectifier circuit of the forward converter adopted the fixed driving voltage, has the dead zone time same as the active clamp circuit, and can improve the conversion efficiency and reduce the loss of the active clamp synchronous rectification forward converter.

Description

technical field [0001] The invention belongs to the field of electronic technology, and relates to a DC / DC converter of active clamp synchronous rectification, especially a forward converter whose secondary adopts self-driven synchronous rectification. Background technique [0002] At present, an active clamp synchronous rectification forward converter usually includes a DC input power supply, an input capacitor, a main transformer T1, a synchronous rectification circuit, a filter circuit, a voltage sampling circuit, an optocoupler feedback circuit, a PWM control circuit and an active clamping circuit composition. Its circuit structure is as figure 1 Shown: the DC input power supply Vin charges the input capacitor C1, and the discharge current of the input capacitor C1 is input to the primary terminal of the main transformer T1 with the same name; the primary terminal of the main transformer T1 with the same name is grounded through an active clamping circuit. The active c...

AI Technical Summary

Problems solved by technology

[0006] In order to solve the loss caused by the drive voltage of the rectifier tube and the freewheeling tube being too high or too low in the synchronous rectification circuit of the existing active clamp synchronous rectification forw

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