Function of fast recovery diode — SUNMATE

It is usually used for rectifying and freewheeling products with higher frequency.

For the input part of the power module, the frequency is not high, so there is no need to use the fast recovery diode, just use the ordinary diode.

Compared with diodes, when the voltage applied at both ends changes from forward to reverse, the response time is generally very short, while when the reverse changes from reverse to forward, the time is relatively long, which is the reverse recovery time. When diodes are used as high-frequency rectifiers, the reverse recovery time is required to be very short. At this time, fast recovery diodes (FRD), higher ultrafast recovery diodes (SRD), switching diodes are required, The fastest is Schottky tube (its principle is different from the above diodes)

Fast recovery diode (FRD) is a kind of semiconductor diode with good switching characteristics and short reverse recovery time. It is mainly used in switching power supply, PWM pulse width modulator, frequency converter and other electronic circuits as high-frequency rectifier diode, freewheeling diode or damping diode.

The internal structure of fast recovery diode is different from that of ordinary PN junction diode. It belongs to pin junction diode, that is, the base region I is added between p-type silicon material and n-type silicon material to form pin silicon chip. Because the base region is very thin and the reverse recovery charge is very 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.

Generally, to-220fp plastic packaging is used for fast recovery diode tubes of 5~20a, to-3p plastic packaging with metal heat sink on the top is used for high-power fast recovery diodes above 20a, and DO-41, DO-15 or DO-27 plastic packaging is used for fast recovery diodes below 5A.