Variable-frequency pulse-width-modulation for zero-voltage switching in a boost DC-DC regulator

Abstract

A technique for operating a pulse-width-modulated (PWM) dc-dc regulator in the boost mode while switching the MOSFET when the drain-to-source potential is near zero volts was developed and is described in this thesis. This is accomplished by using frequency-modulation in addition to pulse-width-modulation. Zero-voltage switching will provide power converter designers an alternative for designing high-frequency converters with minimal transient turn-on losses, the predominant form of converter losses experienced in high frequency operation. High frequency operation will result in smaller reactive components, which produce higher power density converters, as well as increasing the transient response of the regulated converter. In addition to allowing for high frequency operation, the design exhibits many desirable power switch properties, such as limiting the peak voltage to the output voltage level and operating with the minimum possible current levels for a given power requirement. A circuit built and tested utilizing zero-voltage switching in a regulated boost converter verified the principles of operation for yielding a high-efficiency, high-frequency converter.