电源变换器中电流模式和电压模式相互转化

Conversion of current mode and voltage mode for switching power supply converter

介绍了电流模式和电压模式的工作原理,电压模式为单环的自动调节系统,电流模式为双环的自动调节系统,描述了两种工作模式它们各自的优缺点;探讨了理想的电压模式利用输出电容ESR取样加入平均电流模式的工作过程,论证了电压模式输出使用电解电容系统更容易稳定的原因;探讨了通过输入电压前馈加入电流模式的工作过程,并推导了电流取样信号和输入电压的关系;讨论电流模式在输出轻载或无负载、在使用大的电感以及在占空比大于0.5加入斜坡补偿三种工作条件下,系统会从电流模式进入电压模式工作过程。

The operation principle of voltage mode with single stage automatic adjustment system and current mode with dual stages automatic adjustment system in switching power supply are introduced in this paper.Their advantages and disadvantages are also presented in detail.The process to form average current mode with ESR equivalent series resistance of output capacitance in ideal voltage mode is discussed,which justify that the system with output electric capacitance in voltage mode is relatively stable.The operation process to form current mode in voltage mode with input voltage forward-back is discussed and deduce the relation between current signal and input voltage.In the end,the process that the system goes into voltage mode from current mode at three conditions of output light and no load,high inductance and the duty cycle above 0.5 with slope compensation are discussed.