What are the causes and effects of reverse leakage current in fast recovery diodes?

What are the causes and effects of reverse leakage current in fast recovery diodes?

The reverse leakage current IR of the fast recovery diodes is an important parameter that determines the loss of the fast recovery diode in the off state. In the equivalent circuit model, a high resistance resistor Rp is used to simulate the magnitude of the leakage current. Generally speaking, the reverse leakage current should be very small. However, during the reverse transition process, the effect of the peak IRM of the reverse current on the off loss cannot be ignored, and the reverse leakage current increases exponentially with the increase of the junction temperature. The magnitude of the leakage current is closely related to the manufacturing process of the PN junction. When the temperature increases, the reverse leakage current of the fast recovery diodes needs to increase. This leakage current will not saturate, causing the junction temperature of the PN junction to further increase, resulting in a higher reverse leakage current that heats up even more until it burns out.

The reverse rated voltage (also known as reverse blocking voltage) of a fast recovery diode, also known as Peak InverseVoltage (PIV), is determined by the allowable reverse leakage current. When the reverse voltage applied to the diode is greater than the PIV value, the reverse leakage current will significantly increase.

Reverse leakage current measurement of fast recovery diodes:

Connect a resistance, Ammeter and diode in series, and add reverse voltage. The reading of Ammeter is reverse leakage.