First. Ordinary silicon diodes and Schottky diodes

1. The same

Both diodes are unidirectionally conductive and can be used in rectification applications.

2. Difference

The difference is that the withstand voltage of ordinary silicon diodes can be made higher, but its recovery speed is low, and it can only be used in low-frequency rectification. Serious heating and burning; the withstand voltage of Schottky diodes is often low, but its recovery speed is fast and can be used in high-frequency applications, so switching power supplies use such diodes as rectifier output. The tube temperature is still very high.

Except for the model, there is generally no difference between ordinary silicon diodes and Schottky diodes in appearance, but the forward voltage drop can be measured to make the difference. Directly use a digital multimeter to measure (small current) ordinary diodes above 0.5V, Schottky diodes at 0.3 Below V, the ordinary diode is about 0.8V at high current, and the Schottky diode is below 0.5V; SR350 means 3A50V. Another Schottky diode withstand voltage is generally below 100V, no more than 150V.

 

Second, the difference between fast recovery diodes and Schottky diodes

Fast recovery diodes refer to diodes with a very short reverse recovery time (below 5us), which are mostly gold-doped in the process. Some of them use a PN junction structure, and some use an improved PIN structure. Its forward voltage drop is higher than that of ordinary diodes (1-2V), and its reverse withstand voltage is mostly below 1200V. In terms of performance, it can be divided into two levels: fast recovery and ultra-fast recovery. The former reverse recovery time is hundreds of nanoseconds or longer, while the latter is less than 100 nanoseconds.

Schottky diode is a diode based on the potential barrier formed by metal and semiconductor contact, referred to as Schottky Barrier Diode, which has a forward voltage drop (0.4--0.5V) and a very short reverse recovery time ( 10-40 nanoseconds), and the reverse leakage current is large, the withstand voltage is low, generally lower than 150V, and it is mostly used in low-voltage occasions.

These two types of tubes are usually used for switching power supplies.

The advantages of fast recovery diodes are low power consumption, high current, and ultra-high speed. The electrical characteristics are not much different

Fast recovery diodes use gold-doped, simple diffusion and other processes in the manufacturing process, which can achieve higher switching speed and higher withstand voltage. At present, fast recovery diodes are mainly used as rectifier components in inverter power supplies.