基于数字控制PSM流限模式的AC-DC变换器

An AC-DC Converter Based on Digitally Controlled PSM Current Limit Mode

设计了一种应用于反激式AC-DC变换器的控制芯片。为了提高AC-DC变换器的工作稳定性,降低成本,实现全负载范围较高的转换效率,采用PSM流限控制模式。PSM流限控制模式结构简单,可有效降低系统成本。系统根据负载情况分段调节流限值,实现各负载点较高的转换效率,减小输出电压纹波,避免轻载时开关频率进入音频范围。芯片主要采用数字控制,具有高稳定性和低功耗,内置700 V耐压功率MOSFET。整个系统采用3μm 700 V BCD工艺实现。

A controller IC for flyback AC-DC converter was designed.To achieve improved stability and higher efficiency for different load applications with lower cost,a novel PSM current limit mode was adopted,which is simple and cost effective.The controller achieved high efficiency,low output ripple and zero audible noise by adjusting current limit for different loads.With digital control,the circuit was more stable and consumed less power.The converter was designed and implemented in 3 μm 700 V BCD technology.A 700 V power MOSFET was incorporated onto the chip.