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

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 2 MHz 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.