Fast response digital PID control circuit for DC-DC converter

This paper presents a new fast response digital PID control circuit for dc-dc converter and its dynamic characteristics. In the conventional digital PID control method, the sampling rate is single and the calculation process of P-I-D control is series. On the other hand, in the proposed method, the sampling rate is divided each sampling period and the calculation process of P and I-D controls is parallel. The sampling interval and points for I-D control are same to the conventional method. However, the sampling point of P control is oversampling during the switching period of the converter. The simulation and experiment results of the output voltage against the step change of the load are discussed. As a result, it is revealed experimentally that the fast transient response is obtained. The convergence time of output voltage of proposed method is less than 1/3 of that of conventional one when the output smoothing capacitance becomes small.