How is the reverse recovery time of a fast recovery diode defined?

The biggest difference between fast recovery diodes and ordinary rectifier diodes is the reverse recovery time of fast recovery diodes. How is the reverse recovery time of a fast recovery diode defined?

Below, we will popularize the basic knowledge for everyone:

The definition of the reverse recovery time (tr) of a fast recovery diode is the time interval during which the current transitions from forward to a specified low value through zero. It is an important technical indicator for measuring the performance of high-frequency freewheeling and rectifier devices.

In a fast recovery diode, IF is the forward current and IRM is the maximum reverse recovery current. Irr is the reverse recovery current, usually specified as Irr=0.1IRM. When t ≤ t0, the forward current I=IF. When t>t0, due to the sudden change of the forward voltage on the rectifier device to the reverse voltage, the forward current rapidly decreases. At t=t1, I=0。 Then a reverse current IR flows through the rectifier device, and IR gradually increases; At time t=t2, the maximum reverse recovery power is reached

Stream IRM value.

Afterwards, under the action of forward voltage, the reverse current gradually decreases and reaches the specified value Irr at t=t3. The reverse recovery process from t2 to t3 is similar to the discharge process of capacitors.

It can be seen that parameters such as reverse recovery time form a gap compared to fast recovery diodes and ordinary rectifier diodes.