FPGA-Based Digital Pulsewidth Modulator With Time Resolution Under 2 ns

This paper proposes a new digital pulsewidth modulation (DPWM) architecture that takes advantage of the field-programmable gate array's (FPGA) advanced characteristics, especially the delay-locked loop (DLLs) present in almost every FPGA. The proposed DPWM combines a synchronous (counter-based) block with an asynchronous block for increased resolution without unnecessarily increasing the clock frequency. The experimental results show an implementation in a low-cost FPGA (Xilinx Spartan-3) that uses an external 32 MHz clock for a final time resolution under 2 ns.