Switching converter, operating method thereof and controller circuit

Abstract

A phase shifted full bridge (PSFB) switching converter, a method of operation thereof, and a controller circuit are disclosed. The PSFB switching converter includes: a transformer having a primary winding and a secondary winding; an input capacitor coupled to the primary winding via a first transistor full bridge; an output inductor coupled to the secondary winding via a synchronous rectifier circuit including at least one first transistor and at least one second transistor; and a controller circuit for generating switching signals for the rectifier circuit to operate the PSFB switching converter in reverse direction. In this regard, during a startup phase, at the beginning of which the input capacitor is substantially discharged, the at least one first transistor is switched on in each switching cycle to allow an inductor current to pass from an output node, via the output inductor and the secondary winding, to a ground node, wherein the at least one first transistor is again switched off when the inductor current reaches a threshold value. A new cycle begins when or some time after the inductor current has again reached zero.

Description

technical field [0001] The present disclosure relates to the field of switching converters, in particular so-called phase shifted full bridge (PSFB) converters. Background technique [0002] PSFB converters can be used for DC-DC conversion in various applications. A PSFB converter provides voltage conversion and galvanic isolation from the input line voltage because the converter topology includes a transformer. Like other resonant or quasi-resonant converters, PSFB converters can be operated to perform so-called zero-voltage switching (ZVS) with respect to the power transistors that switch the primary current through the transformer. [0003] A bidirectional PSFB converter may require an auxiliary circuit for a so-called cold start, during which large overshoots may occur in the electronic switches coupled to the secondary side of the transformer. Although some methods to reduce overshoot already exist, further improvements are still needed. In particular, in many cases ...

AI Technical Summary

Problems solved by technology

Although some methods of reducing overshoot already exist, further improvements are still needed

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