移相谐振PWM控制器UC3875在开关电源中的应用

Application of Phase Shifting and Resonance PWM Controller UC3875 in the SMPS

开关损耗是开关电源高频化的主要障碍之一,开关管共同导通而留的死区时间,限制了开关电源工作频率的提高,而移相谐振PWM技术正是利用死区时间,通过谐振腔使开关管输出电容上的电压迅速放电,从而实现零电压或零电流开关,减少开关损耗和降低噪声干扰。文章介绍了移相谐振PWM控制器UC3875的工作原理及应用。

Switching loss of switching mode power supply（ SMPS） is one of main obstacles which causes switch power to be high frequency. The dead-time led by switch tubes getting -through at same time prevents the switching mode power supply from getting a higher frequency. However, it is just the dead-time that phaes-shift and resonance PWM utilizes by rapid discharge from the capacitors on switch tubes via resonance cavity to realize zero voltage or zero current switching, so as to reduce the switch loss and noise. This text introduces operation principle and application of phase shift and resonance PWM controller UC3875.