FPGA-based combined PWM-PFM technique to control DC-DC converters

Abstract

This paper describes a combined Pulse Width Modulation (PWM)-Pulse Frequency Modulation (PFM) technique implemented in a Field Programmable Gate Array (FPGA) to control DC-DC converters. This technique changes the mode of operation from PWM to PFM with the change in the load condition. The efficiency of the proposed technique is determined by implementing a DC-DC converter and calculating the conduction losses, switching losses, and ripple voltages at different load values. Furthermore, the efficiency of the converter based on the proposed technique is compared to the efficiency of processor-based implementation. The results show that the efficiency of the converter with the FPGA-based technique is higher than the efficiency of the converter with processor based technique.