Hybrid DPWM with Digital Delay-Locked Loop

Abstract

This paper introduces a fully synthesizable hybrid digital pulse width modulator (DPWM). The DPWM includes a digital delay locked loop around a delay-line with discretely programmable delay cells to achieve constant-frequency clocked operation with the best possible resolution over a range of process or temperature variations. The DPWM module can implement trailing-edge, leading-edge or triangular modulation. It includes two outputs with programmable dead-times, suitable for DC-DC converters with synchronous rectifiers. The DPWM module is well suited for FPGA or custom chip implementation. Experimental results are shown for a 780 KHz, 10-bit FPGA realization