Zero-Voltage-Switched Resonant Half-Bridge High-Voltage DC- DC Converter

Half-bridge resonant inversion incorporating zero-voltage switching has been combined with resonant rectification to produce high-frequency, resonant dc-dc converters operating at frequencies up to 15 MHz and capable of delivering 125 watts at a regulated 5 volts from an input of 200 to 400 volts. Use of the half bridge allows converter operation with an input of 400 volts, placing only 410 volts maximum stress on the switching FETs. Zero-voltage switching and resonant rectification insure low loss at high frequencies, with overall converter efficiency of >78% observed at full load in a 6MHz model. The fully resonant designs used for these converters also minimize noise output. At full load and 300 volts input, the output ripple on 5 volts was measured to be only 5 millivolts. Preliminary work on the 15 MHz model indicates that a power density of better than 30 watts/in sup 3 will be achievable.