What is a Fast Recovery Diode?

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Editorial Team - everything PE

Sep 19, 2021

fast recovery diode (FRD) is a type of power diode that has a short reverse recovery time for high-frequency rectification. The recovery time is the finite amount of time taken by a diode to discharge (during conducting state, it stored the charges) when switching from the conducting to the blocking state. They are designed to handle high voltage and high current levels than the conventional diode. 

Fast recovery diode consists of two terminals - anode & cathode, and functions the same as that of a conventional diode, but differs in construction. The major construction difference is the presence of the recombination centers in the fast recovery diode. A conventional PN junction diode is formed by joining n-type and p-type semiconductor materials. Whereas in the fast recovery diode, Gold (Au) is added as a dopant to the Gallium Arsenide (GaAs) semiconductor.  This leads to an increment of the number of recombination centers in the forbidden band, which results in a reduction of reverse recovery time at the instant of switching. This construction difference ensures the fast recovery diode exhibit a very small reverse recovery time than a normal diode.

Fast recovery diodes are ideal for use in applications such as switching power supplies, DC-DC converters, AC-DC adaptors/chargers, inverters, motor control & drives, power converter & inverter for wind turbines, commercial, construction & agricultural vehicles (CAV), UPS, and PFC.