A novel fast average current mode digital control for DC-DC converter

Abstract

This paper introduces a novel fast average current mode digital control for dc-dc converter. The proposed control circuit has two features. First, the voltage controlled oscillator (VCO) is used for the switch/reactor current detection. The VCO is low price and can transform to digital value quickly without complex calculation when the current is detected. Second, the digital feedback value of output voltage can be calculated by the digital PID control with the fast P process. In the digital PID control with the fast P process, P and ID control are parallel processing and the sampling period of P control is shorter than the switching period due to shrink the delay time of output voltage calculation. In this paper, the input voltage or output current fluctuations characteristics of proposed circuit are studied. As results, the proposed method is superior transient response both of input voltage fluctuations and the output current ones in spite of small capacitance when the same coefficient of PID control is used.