In this post we are going to discuss diode reverse recovery, all the semiconductor devices have the reverse recovery phenomenon at their normal operation.
At the theoretical aspect, the reverse recovery of the diode has no importance, but in the practical scenario, the diode reverse recovery time and diode reverse recovery current had an impact on the working of the diode.
Reverse recovery characteristics of diode
The figure shows the illustration of reverse recovery characteristics of the diode, this characteristics curve is the same for almost all diodes.
Tf = forward recovery time
trr = reverse recovery time
- As when diode switches from forward to reverse biased condition, as reverse current flows for a short period is called the reverse recovery time
- This is indicated in this characteristics graph.
Diode reverse recovery time equation
trr= ts + tt
tt = transition time (It is the time between zero crossings of forwarding current and peak reverse current Irm)
- During tt charged stored at depletion region
ts = it is measured from the instant Irm where 0.25 Irm is reached
ts/ tt = softness factor
Diode reverse recovery time
The flow of current in reverse direction happens only for a short period typical at normal diode, generally, the recovery time of diode will be recorded between 150 to 200 ns, and fast recovery diode used in high voltage and high-speed switching applications.
Schottky diode reverse recovery time
The Schottky diode had significance in recovery time, the speed is only limited by the junction capacitance.
The Schottky diode had ~100ps for the small-signal diodes and up to tens of nanoseconds for special high capacitance power diodes.
Body diode reverse recovery
The reverse recovery current of the MOSFET body diode is 2A, at different temperatures.
Diode reverse recovery current
When diode switches from forward to reverse bias, practically it switches at diode blocks the reverse current, but this will not happen due to the presence of minority charged carriers at each side of the p-n junction.
The reverse recovery current is proportional to the forward current of the diode and the amount of applied voltage in the reverse direction.
Diode reverse recovery losses
The losses caused by diode reverse recovery are very minimal, the temperature of the diode increases, so naturally, the efficiency of the device will be affected.