A delta-sigma modulated Class D current-source resonant boost converter

This paper proposes a Class D current-source resonant boost converter, which is controlled with the 1-bit delta-sigma modulator. The 1-bit delta-sigma modulator, which is an analog to digital (A/D) converter for digital audio amplifiers, generates a 1-bit (1/0) signal based on the input signal. This `periodical' output signal has an advantage in driving resonant converters. Class D voltage-source resonant converter driven by the 1-bit delta-sigma modulator maintains zero-current switching (ZCS) with the `buck' characteristic. In this study the 1-bit delta-sigma modulator is applied to a Class D current-source resonant converter. In contrast, the converter has the `boost' characteristic with maintaining zero-voltage switching (ZVS). The theoretical approach, the simulation results, and the experimental results are introduced. In circuit experiments, the output voltages 8.73 V to 17.2 V were obtained from the input voltage 5.0 V with the load resistance 97.3 Ω at 200.0 kHz, where the measured power conversion efficiencies were more than 82.1 %. No specific sub-harmonics were observed in frequency domain.