Limit-Cycle Free, Digitally-Controlled Boost Converter Based on DDPWM

Abstract

In this paper, a digitally controlled boost DC-DC power converter featuring a high-resolution Dyadic Digital Pulse Width Modulator (DDPWM) is proposed to achieve Limit-Cycle oscillations (LCOs)-free operation, high DC accuracy, low output voltage ripple at high switching frequency. The effectiveness of the DDPWM in suppressing the onset of LCOs, increasing DC accuracy, and reducing output ripple is verified by both Simulink/Modelsim co-simulations and experimental testing on a 7-10V input, 13.8V output boost converter operated at 1.17MHz switching frequency. Thanks to the proposed modulator, improvement of more than 6X DC accuracy is achieved compared to a plain digital PWM. Moreover, approximately 3X less output ripple in comparison to a digital PWM with thermometric dithering is achieved.

Keywords

• Digital pulse width modulator (DPWM)
• dyadic digital pulse width modulation (DDPWM)
• digitally controlled boost converter
• HDL verilog
• limit-cycles oscillations (LCOs)
• simulink/modelsim co-simulation