一种硬开关全桥输出带预偏电压启动的方案

A Solution of Pre-Bias Start up for Hard Switching Full Bridge

为了防止带有同步整流的硬开关全桥在预偏置启动时出现反灌电流的现象,提出了一种实现简单、性能优越的带预偏电压启动的方案。该方法是在电源启动前,先检测输入输出电压,然后将参考值与环路的输出设置成与输出电压相对应值,最后使输出电压在预偏电压处单调上升。在输入电压为48V,输出电压为12V/20A的电源模块上验证了该方法。通过实验证明,新的方法无需增加硬件成本,并且具有可靠性高、实现简单、效率高的优点。

The pre-bias voltage can produce negative current in Hard Switching Full Bridge （HSFB） with synchronous rectification. After analyzing the causes of abnormal start up of pre-bias voltage at output, a new solution for solving this problem is presented. This method detects output and input voltage before starting up, and sets reference and loop output with related value at the same time, and then start up at this value. A HSFB module, which input is 48 V and output is 12V/20A, is taken as example to verify the method. The experiment shows that the new solution does not require addition- al hardware costs. And it has the advantage of high reliability, simplicity and efficiency.