开关电源的缓冲电路设计

随着开关电源工作频率的提高,开关器件承受很大的热量和电应力,从而形成过电压。为此,常常需要设置各种缓冲电路对其进行抑制。重点分析比较了三种缓冲电路,并指出了各自的特点及设计要点。RCD缓冲电路的箝位电压随电阻减小而减小,但损耗增大;LCD缓冲电路的LC谐振频率要求小于开关频率;能量回馈缓冲电路的箝位电压较低,不需要额外的电感。最后,给出了LCD缓冲电路的设计结果,实现了无损耗箝位。

Design of a Snubber Circuit for Switching Power Supply

Three snubber circuits to prevent switching power supply from over-voltage are investigated.Their advantages and design considerations are analyzed and compared.For RCD snubber circuit,the clamp voltage can be reduced by reducing its resistor value,which,however,leads to higher power losses.For LCD snubber circuit,the resonant frequency is supposed to be lower than the switching frequency.The energy regenerative snubber circuit has relatively lower clamp voltage,requiring no extra inductor.Finally,design of LCD snubber circuit is presented,which achieves lossless clamping.