REVERSE RECOVERY OF POWER PN JUNCTION DIODES

A quasi-steady state approximation is used to derive expressions for t he waveforms of minority carrier charge stored in p(+)nn(+) power junc tion 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 a nd the diode current and voltage waveforms are predicted. It is shown that three frequency ranges can be distinguished: (1) low-frequency ra nge in which the reverse recovery is negligible, (2) mid-frequency ran ge in which the reverse recovery is detrimental, but the diode is stil l of practical value, and (3) high-frequency range where the diode doe s not exhibit its rectifying properties. A simple method for measuring the minority carrier lifetime is proposed. Experimental results are g iven for an MR826 East-recovery pn junction diode and a 31DQ06 Schottk y diode for operating frequencies of up to 10 MHz. The theoretical and experimental results were in good agreement.