FPGA-based DPWM for digitally controlled high-frequency DC-DC SMPS

Abstract

Digital pulse-width modulator (DPWM) is known as the critical module in digital controller application for high-frequency switching mode power supply (SMPS). This paper presents a new Hybrid DPWM architecture operating at high frequency with high resolution. The proposed DPWM takes advantage of the phase-shift function of Digital Clock Manager (DCM) in FPGA, and combines a counter-comparator with a digital dither block. To verify the proposed DPWM, an 11-bit prototype DPWM is implemented on a FPGA-based digitally controlled high-frequency buck converter. Experimental results with constant switching frequency up to 2MHz validate the functionality of the proposed DPWM. This hybrid architecture can operate at high switching frequency while reduce clock frequency so as to save power consumption.