Types of Power Diodes

The power diodes are classified into three types based on their reverse recovery characteristics. They are:

1. General purpose diodes
2. Fast recovery diodes
3. Schottky diodes

General purpose diodes

The general purpose diodes have high reverse recovery time typical in the order of 25μs. Hence these diodes cannot be used for fast switching applications. They are available with voltage ratings ranging from 50V to 5000V with current ratings ranging from 1 A to several thousand amperes. These diodes are used in battery charging, traction drives and uninterruptible power supplies (UPS) etc.

Fast-recovery diodes

These diodes will have less reverse recovery time of about 5μs or less. These diodes are available with their voltage and current ratings ranging from 50V to 3kV and 1 A to several thousand amperes respectively. These diodes are used in choppers, SMPS – switched mode power supplies, and commutation circuits etc.

Schottky Diodes

These types of diodes have no reverse recovery time and can be turned off much faster than a normal p-n junction diode. These diodes use metal to semiconductor junction instead of p-n junction. The forward current in schottky diode is only due to electrons and there are no holes. Hence as there are no holes there is no storage charge and no reverse recovery time.

The schottky diodes are used in high frequency instrumentation and switching power supplies and are available with current rating of about 1 to 300 A.