A 1-MHz 5-kV Power Supply Applying SiC Diodes and GaN HEMT Cascode MOSFETs in Soft Switching

A new high-voltage (HV) power supply based on the half-wave Cockcroft-Walton voltage multiplier topology is introduced. The proposed power supply operates at 1 MHz (at least ten times faster than conventional HV multipliers) and exhibits a very stable output voltage with minimal ripple (<0.1%). The proposed power supply has a high power density due to the high frequency and is also highly efficient (>90%). The high operation frequency and efficiency were facilitated by a critical design that applies softly switched wide-bandgap devices (silicon carbide diodes and gallium nitride high electron mobility transistor cascode MOSFETS) in full bridge cascaded by a voltage multiplier topology. Experimental evidence is provided from a prototype unit that raises the voltage from 300 V to 5 kV, with a 93% efficiency.