一种可切换工作模式的反激开关电源

反激变换器存在电感电流连续模式（CCM）和断续模式（DCM）两种工作状态。通常选取处于CCM与DCM的临界状态作为工作点，设计反激开关电源的补偿回路。该折衷方案虽能兼顾两种工作模式，但存在带宽较小、动态响应差的问题，且在轻载情况下尤为突出。针对该问题设计了一种可切换工作模式的反激开关电源，对CCM和DCM模式分别设计环路补偿网络，通过变压器原边电流判断负载情况，进而切换补偿网络，实现电源工作模式的切换。设计了输出功率120 W的反激开关电源样机，进行仿真和样机性能测试，试验结果表明，电源不仅能根据负载情况切换工作模式，而且轻载时具有很好的动态响应，验证了该方案的有效性，与预期设计结果相符。

A flyback switching power supply with switchable working mode

Flyback converter has two working states: continuous inductance current mode (CCM) and discontinuous mode (DCM). Usually, the critical state of CCM and DCM is selected as the working point to design the compensation loop of flyback switching power supply. Although the compromise scheme can take into account two working modes, it has the problems of small bandwidth and poor dynamic response, especially under light load. To solve this problem, a flyback switching power supply with switchable working mode is designed. The loop compensation network is designed for CCM and DCM modes respectively. The load condition is judged by the primary side current of the transformer, and then the compensation network is switched to realize the switching mode of the power supply. A prototype flyback switching power supply with output power of 120W was designed, and the simulation and performance test of the prototype were carried out. The test results show that the power supply can not only switch the working mode according to the load, but also has a good dynamic response under light load. The effectiveness of the scheme is verified, which is consistent with the expected design results.