A novel A-D conversion for digital control switching power supply

This paper proposes a novel A-D conversion method for the digital P-I-D control in order to improve the transient response in the switching power supply. The P-I-D control circuit has a delay time mainly due to the calculation and sampling. This delay heavily affects the transient responses. In the presented method, the P-I-D is divided into two parts, the P control and the I-D control, independently. In the P control, the high speed and low resolution A-D converter is used to realize the quick control for the transient response. In the I-D control, the high resolution and low speed A-D converter is used to realize the accurate regulation characteristics. The cost of proposed method which is used two A-D converter is lower than the high resolution and high speed A-D converter. As result, it is confirmed that the proposed method have equivalent transient response to the high-cost one. This suggests that the proposed method is the efficient approach to realize the high performance design of the control circuit in low cost.