Reverse recovery of power pn junction diodes

A quasi-steady state approximation is used to derive expressions for the waveforms of minority carrier charge stored in p(+)nn(+) power junction diodes driven by large-signal sinusoidal and ramp voltages. These waveforms are derived by solving a diode charge-control differential equation. Using the charge waveforms, the storage time is determined and the diode current and voltage waveforms are predicted. It is shown that three frequency ranges can be distinguished: (1) low-frequency range in which the reverse recovery is negligible, (2) mid-frequency range in which the reverse recovery is detrimental, but the diode is still of practical value, and (3) high-frequency range where the diode does not exhibit its rectifying properties. A simple method for measuring the minority carrier lifetime is proposed. Experimental results are given for an MR826 East-recovery pn junction diode and a 31DQ06 Schottky diode for operating frequencies of up to 10 MHz. The theoretical and experimental results were in good agreement.