Implementing a small signal self-analysis of power stage in a digitally controlled SMPS

Abstract:
In order to achieve the best step response with the lowest over/under-shoot of regulated value, it is important to have the correct compensation of a power supply. To set the poles and zeros of compensation correctly, the mathematical model of the converter needs to be known. Unfortunately, these are usually very simplified and do not calculate with all the parameters of a real system. For more enhanced compensation, the real plant transfer function needs to be known. There are many tools for measuring this transfer in an analog controlled power supply, but they are unfortunately not usable for digital control. In this paper, the method of employment same driving microcontroller for extracting bode plot of power stage is presented.