Patent ID: 9729072
Date: 2017-08-08
CPC Classifications: H02M,Y02B,Y02P

Claim:
1. A resonant converter, comprising: a first switch on a primary side and a second switch coupled to the first switch; a first synchronous rectification switch on a secondary side configured to conduct according to a switching operation of the first switch; a second synchronous rectification switch on the secondary side configured to conduct according to a switching operation of the second switch; and a switch control circuit configured to detect a waveform of one end voltage of at least one of the first synchronous rectification switch and the second synchronous rectification switch, determine one of a below region and an above region of the detected waveform, and differently control conduction duration of the first and second synchronous rectification switches according to a result of the determination, wherein the switch control circuit comprises a mode selector configured to count changes in output detected by comparing the at least one end voltage with a predetermined threshold voltage and select a mode according to a counted result.