同步整流电路中控制器选型与应用研究

同步整流电路,是采用导通电阻非常低(mΩ级)的功率MOSFET,代替普通整流二极管以降低功率损耗的一种技术。同步整流控制芯片是该电路的大脑,当使用功率MOSFET作整流管时,需要栅极电压和被整流的电压相位保持同步才完成,同步整流电路可以很大程度上提升DC/DC变换器的效率。该文设计一款输出功率为24 V/8.3 A的AC/DC电源,基本拓扑为LLC半桥谐振电路和同步整流电流电路,重点讨论同步整流电路选型与设计应用。

Synchronous rectifier circuit is a technology that uses power MOSFET with very low on-resistance(mΩlevel)instead of ordinary rectifier diodes to reduce power loss.The synchronous rectifier control chip is the brain of the circuit.When the power MOSFET is used as the rectifier tube,it needs to be synchronized between the gate voltage and the rectified voltage phase.The synchronous rectifier circuit can greatly improve the efficiency of the DC/DC converter.In this paper,an AC/DC power supply with output power of 24 V 8.3 A is designed.The basic topology is LLC half-bridge resonant circuit and synchronous rectifier current circuit.The selection and design application of synchronous rectifier circuit are discussed in detail.