A novel delta-sigma modulated DC-DC power converter utilizing dither signal

Abstract

Delta-sigma modulator is effectively used as a PWM pattern generator for high-frequency switching mode inverters. However, in the case of applying a delta-sigma modulator for switched mode DC-DC converters, the significant features cannot be realized. In this paper, the authors propose a novel delta-sigma modulation circuit which consists of two stage delta-sigma modulators. In the first stage, dither signal is added to reference input signal. In the second stage, a feedback signal of delta-sigma modulator is altered to continuous signal of DC-DC converter output. As a result, the proposed delta-sigma modulation circuit has the inherent nature of spread spectrum and automatic amplitude control scheme for the chopper type DC-DC converter.