1. What is a fast recovery diode

Fast recovery diodes are commonly used in higher frequency rectification and freewheeling products. Generally used for the input part of the power module, the frequency is not high, no need to use fast recovery diodes, just use ordinary diodes.

Compared with a diode, when the voltage applied across its two ends changes from forward to reverse, the response time is generally very short, while on the contrary, when the voltage changes from reverse to forward, the time is relatively long, which is the reverse recovery time. When the diode is used for high-frequency rectification, etc., the reverse recovery time is required to be very short. At this time, a fast recovery diode (FRD), a higher ultra-fast recovery diode (SRD), a switching diode, and the fastest is Schottky. tube (its principle is different from the above several diodes).

2. Fast recovery diode characteristics

Fast recovery diode (FRD for short) is a semiconductor diode with good switching characteristics and short reverse recovery time. It is mainly used in switching power supplies, PWM pulse width modulators, frequency converters and other electronic circuits. Freewheeling diodes or damping diodes are used.

The internal structure of the fast recovery diode is different from the ordinary PN junction diode. It belongs to the PIN junction diode, that is, a base region I is added between the P-type silicon material and the N-type silicon material to form a PIN silicon wafer. Because the base region is very thin and the reverse recovery charge is small, the reverse recovery time of the fast recovery diode is short, the forward voltage drop is low, and the reverse breakdown voltage (withstand voltage value) is high.

3. Features of fast recovery diode package type

Usually, the fast recovery diode tube of 5~20A is packaged in TO-220FP plastic, the high-power fast recovery diode above 20A is packaged with TO-3P plastic with a metal heat sink on the top, and the fast recovery diode below 5A is packaged with DO-41, Specifications such as DO–15 or DO–27 plastic package.