Current Cutoff Behavior Observed When Twin Rectifiers Combine Their DC Output Power in Parallel

Abstract

This paper theoretically discovers a cutoff behavior of the DC current in twin rectifiers operating in parallel. The formulation of the circuit starts from a single rectifier focusing on its flow-angle equation. The DC output voltage and current formulas are derived in terms of the RF input power and load resistance. We then consider twin rectifiers connected in parallel at the DC output port. When the twins are excited with different RF amplitudes, a specific input power ratio exists whereby the weaker rectifier goes to sleep. We name this behavior rectifier's current cutoff, and the specific cutoff power ratio is theoretically predicted as –13.3 dB. A harmonic-balance simulation and proof experiment are performed at an input frequency 6.78 MHz and power up to 100 W in total. Both simulation and experiment successfully confirm the current cutoff behavior.