Reverse recovery time

Posted by AJ × 23:46

• Denoted by trr.

• In FB condition, large number of electrons from n-type progressing through p-type

and large number of holes in p-type is a requirement for conduction. The electrons in

p-type and holes progressing through n-type establish a large number of minority

carriers in each material.

• Now if the diode is changed from FB to RB

• The diode will not instantaneously react to this sudden change. Because of the large

number of minority carriers in each material, the current sustains in diode for a time ts

storage time which is required for minority carriers to return to their majority carrier

state in the opposite material.

• Eventually current will reduce to non conduction levels.

• This time is tt transition interval

• Hence trr= ts + tt

• This is very important consideration in high frequency operation.

• Commercially available diodes have reverse recovery time of few nano seconds to

1micro second.

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