Investigation into the Reverse Recovery Dynamics of High-Voltage Fast Recovery Diodes

In high-voltage power supplies (HVPS), DC-DC conversion is typically achieved by first converting the DC input to high-frequency AC. This AC is then isolated, rectified, and further boosted with a high-frequency voltage multiplier circuit to achieve a high DC output. For such high-frequency rectification, the selection of high-performance diodes can be difficult since several competing factors need to be traded off. The reverse recovery time ($t_{r r}$) of diodes is a critical parameter that influences the performance of voltage multipliers, particularly in highvoltage applications. This paper explores the factors affecting reverse recovery parameters and an experimental investigation of reverse recovery time of high-voltage fast recovery diodes. The diodes are tested using low-amplitude, high-frequency alternating waveforms generated by a function generator, as well as through a full-bridge square-wave inverter configuration. Two high-performance high-voltage diodes, namely the UX-FOB $8 \mathrm{kV}, 500 \mathrm{~mA}$, and HHV80020 $20 \mathrm{kV}, 0.8 \mathrm{~A}$, are compared experimentally for their high-frequency operation. The diode reverse recovery waveforms obtained using both test circuits are presented. An analysis for finding the reverse recovery power loss using experimentally measured waveforms is also presented.