High-voltage diodes for power frequency seem like the most straightforward choice in 50Hz/60Hz rectifier circuits-they don't require fast recovery characteristics, ultra-low leakage current, or complex drive circuits; even their datasheets are half the thickness of those for high-frequency diodes. However, power frequency applications present a unique engineering challenge: the current is often large and lasts for a long time, meaning that conduction losses are continuous rather than intermittent, placing very direct and even demanding requirements on the diode's heat dissipation capabilities.
If a fast recovery diode optimized for high frequencies is mistakenly selected for power frequency applications, not only will the benefits of fast recovery be lost, but the conduction losses will actually be higher and the heat generation greater because high-frequency diodes sacrifice VF to shorten TRR. This article analyzes why high-voltage diodes for power frequency can withstand continuous high currents, using the parameter configurations of typical power frequency rectifier circuits.
