Zero current detecting circuit and related synchronous switching power converter

摘要

A zero current detecting circuit is disclosed. The zero current detecting circuit includes a first zero current comparator for determining current variation on an inductor of a synchronous switching power converter so as to accordingly turn off a down-bridge transistor of the synchronous power converter; a second zero current comparator for determining whether the first zero current comparator turns off the down-bridge transistor too early or too late and outputting a comparison result, and a counter coupled to the second zero current comparator for ascending or descending a control bit according to the comparison result.