Is asemi ultrafast recovery diode interchangeable with Schottky diode

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Ultrafast recovery diode ：

In the output circuit of switching power supply , Not only do diodes need to have sufficient withstand voltage , The diode also needs to have better switching characteristics , That is, the reverse recovery time is short . therefore , The rectifier diode of the output circuit usually adopts ultrafast recovery diode . The reverse recovery time means the time required for the diode to turn off from the forward direction , Usually less than 0.5 Microsecond .

Schottky diode ：

Schottky diode is a kind of low energy consumption 、 High current 、 Fast semiconductor components . The reverse recovery time can be as small as a few nanoseconds , The positive pressure drop is only 0.4 Lie about , The rectified current can reach thousands of amperes . Schottky diode and PN There are some differences in the structure and principle of junction diode . The disadvantage of this kind of diode is low reverse withstand voltage , Usually no more than 200 v . It is mainly used in low voltage range and high current situation , Schottky diode is usually used in high current switching power supply . that ASEMI Is ultrafast recovery diode interchangeable with Schottky diode ？

differences ：

Characteristics of ultrafast recovery diode ： Good switching effect , Short reverse recovery time , High pressure resistance , However, due to the large positive pressure drop , High power consumption , Easy to get hot ; Schottky diode has good switching characteristics and reverse recovery ability , The positive pressure drop is relatively small , Relatively low power consumption , Not easy to get hot , But the biggest disadvantage is that the pressure resistance is relatively low , At this stage, the level can reach 250V about , In general, fast recovery diodes are easy to achieve 1000V Even higher .

Ultrafast recovery diodes and Schottky diodes are usually not interchangeable ：

Schottky reverse withstand voltage is low , Decreasing , Mainly used for low-voltage rectifier ;

Ultra fast recovery, high reverse withstand voltage , Large positive pressure drop , Mainly used for high voltage rectifier .

Using Schottky instead of fast recovery is easy to breakdown （ In addition to determining that the withstand voltage meets the requirements ）,

Replacing Schottky with ultra fast recovery has large loss and low efficiency （ In addition to not considering efficiency ）.

If the ultrafast recovery diode is found damaged in the maintenance process , Then ordinary rectifier diodes cannot be used to replace . This is because if an ordinary diode is used to replace the ultrafast recovery diode , The reverse recovery time of ordinary rectifier diode is long （ Usually tens of microseconds ）. When the switching transformer outputs a positive pulse to turn on the diode , The diode has no time to turn off in reverse , The reverse pulse rushed in , It will inevitably cause a large reverse current to the diode , Increase the temperature between diode junctions .