Diode reverse recovery current question

[ljy4468]

Good day

I know that diode reverse recovery current occurs through
i) diode is forward biased
ii) diode current flows
iii) Then, negative bias is applied across diode.
iv) negative current (reverse recovery current) flows a while.

Isn't it??

And then I have a question.
i) diode is forward biased.
ii) but NO diode current flows
iii) then, negative bias is applied
there occurs reverse recovery current??

This is example of PFC boost converter (discontinuous mode).
The book says there's no recovery current at second case.
But I cannot understand.

Thanks in advance.
Regards.

 

[FvM]

Reverse recovery current is caused by stored charge carriers and thus depends on forward bias current. With zero bias current, there is still a reverse current impulse caused by the junction capacitance.

 

[TekUT]

Here is a mathematical derivation of the recovery time formula, this show that the total recovery time is a function proportional to the forward/reverse current ratio.

https://www.tf.uni-kiel.de/matwis/amat/semi_en/kap_8/advanced/t8_1_1.html

Bye
Powermos

 

[newbiedes]

I think FvM has said it all...

 

[Davood Amerion]

In the continuous mode boost converter, before diode current reach to zero, power transistor turn on and force diode to turn off.
but in discontinus mode boost converter, diode current reach to zero and turned off (and reversed biased) before power transistor turn on.

 

[ljy4468]

Thanks to all your answers!

FvM, you says 'With zero bias current, there is still a reverse current impulse caused by the junction capacitance'.

Then how's the amplitude?
How much is the reverse current impulse caused by the junction capacitance in comparison with reverse recovery current caused by stored charge??

Is it negligible amplitude?

Thanks.