Design of smart power synchronous rectifier

摘要

In low-output-voltage DC/DC power converters, power losses due tonthe conduction of rectifying devices are significant. Using synchronousnrectifiers instead of the conventional fast recovery diodes or Schottkyndiodes is an effective solution to this problem in most topologies.nHowever, for synchronous rectifiers to perform effectively, thisnrequires an external gate drive with proper sensing and timing controlncircuits. This can increase the complexity and cost in power converternhardware implementation. For the first time, a smart power synchronousnrectifier (SPSR), which is a two-terminal MOS rectifier, is designed tonovercome this difficulty. The SPSR integrates a simple control unit withna power MOSFET into a smart module to form a self-controlled synchronousnrectifier. It has great advantages over the conventional discretencircuit composition, such as integrated gate control, precise timingnswitching and fast transient response, which are suitable fornapplications in high-frequency pulsewidth modulation (PWM) powernconverter circuits