Adaptive quasi-resonance detection circuit and method

The invention provides an adaptive quasi-resonance detection circuit and method. The theoretical wave crest position is adaptively judged by detecting a resonance period of the voltage of a switch node; the driving delay of a half-bridge driving chip is adaptively sampled by detecting the time difference from the falling edge of a driving signal of a clamping tube of a main control chip to the voltage knee point of the switch node; and accurate wave crest opening of the clamping tube is realized by advancing the theoretical wave crest position by one driving delay. Therefore, the switching loss of a non-complementary active clamping flyback converter is greatly reduced, and the current consistency of reverse excitation of a transformer is greatly improved. 本发明提供一种自适应准谐振检测电路和方法，通过检测开关节点电压的谐振周期，自适应地判断出理论上的波峰位置；通过对主控芯片钳位管驱动信号下降沿到开关节点电压膝点的时间差检测，自适应地采样出半桥驱动芯片的驱动延时；通过在理论上的波峰位置提前一个驱动延时的时间实现钳位管的准确波峰开通。从而，使得非互补有源钳位反激变换器的开关损耗大大降低，变压器反向励磁的电流一致性大大提高。