开关电源中RCD钳位电路研究

Research on RCD Clamp Circuit Of Switching Power Supply

在高频开关电源中,由于反激变换器漏感的存在,反激变换器在开关管关断瞬间会产生很大的尖峰电压,为确保开关管不被损害,须引入钳位电路吸收漏感能量。在无源钳位电路中,RCD钳位电路因结构简单、体积小、成本低而倍受青睐。本文通过使用罗德与施瓦茨(R&S)RTE1104高频示波器和罗德与施瓦茨(R&S)ESRP型电磁干扰接收机测试开关电源中RCD钳位电路关键波形及开关电源传导干扰,并与仿真结果进行对比,验证了RCD钳位电路对开关管波形以及开关电源传导干扰的影响。

In the high-frequency switching power supply,due to the presence of the leakage inductance of the flyback converter,the flyback converter will generate a large peak voltage at the moment of turning off the switching tube.In order to ensure that the switching tube is not damaged,the clamping circuit must be introduced to absorb the leakage energy.In the passive clamp circuit,the RCD clamp circuit is favored because of its simple structure,small size,and low cost.This paper uses the Rohde&Schwarz(R&S)RTE1104 high frequency oscilloscope and Rohde&Schwarz(R&S)ESRP type electromagnetic interference receiver to test the critical waveforms of the RCD clamp circuit and the switching power supply conducted interference in the switching power supply.The simulation results are compared to verify the influence of the RCD clamp circuit on the switch waveform and the conduction interference of the switching power supply.