Now frequently used high-power diode are: general rectifier diodes, fast diodes, fast soft recovery diodes, Schottky diodes. It focuses on the last three.
1) Fast Recovery Diodes (Fast Recovery Diode)
GTO, MCT, IGBT, etc., need a fast diode in parallel therewith, through the load reactive current, reducing the capacitor charging time, while inhibiting the reverse because the load current is induced transient high voltage. The diode must be a fast turn-on and turn-off speed capability, which has a short reverse recovery time trr, a small reverse recovery current IRRM. Internationally fast diodes has reached 2500A / 3000V, 300ns.
2) fast soft recovery diode
Fast soft-recovery diode and said fast diode softer compared to a faster recovery. High-frequency power electronic circuits requires not only fast recovery diode forward recovery characteristics of a good, ie small forward voltage drop transient recovery time is short; also requires reverse recovery characteristics are good, that is the reverse recovery time is short, Reverse recovery charge less, and have a soft recovery characteristics.
3) Schottky diode (Schottky Barrier Diode, abbreviated as SBD)
Schottky barrier diode referred to Schottky diodes. It is not a PN junction, but the use of metal forming metal and semiconductor contacts - the principle of making semiconductor junction. Therefore, SBD, also known as metal - semiconductor (contact) surface barrier diodes or diode. Schottky diode switching speed is very fast, switching losses are very small, the reverse recovery time is very short (as small as a few nanoseconds), particularly suitable for high frequency applications. The forward voltage drop, only about 0.4V, lower than the PN junction diode (about low 0.2V). The rectified current but can reach several thousand mA. These excellent characteristics are fast recovery diodes can not match. But its reverse breakdown voltage is relatively low, most not more than 60V, only up to about 100V, the reverse leakage current is greater than the PN junction diode.
The following table lists the Schottky diodes and fast recovery diodes, fast recovery diodes, high-frequency silicon rectifier diodes, silicon diodes high-speed switching performance comparison. Seen from the table, high-speed switching diode trr silicon, although extremely low, but the average rectified current is very small, it can not be a large current rectification.
