How does Schottky diode conduct electricity? — SUNMATE

Schottky diode has the advantages of low impedance, small forward voltage drop and fast recovery, so it is often used in high-frequency high-current rectification and power-down protection lines. Schottky diode is also a conductor with excellent conductivity. How does Schottky diode conduct electricity?

Unidirectional conductivity is the most important characteristic of Schottky diode. In the circuit, the current can only flow in and out of the positive pole of the Schottky diode. The forward and reverse characteristics of Schottky diodes are explained by simple experiments.

The forward characteristic is similar to that in the electronic circuit, if the positive pole of the Schottky diode is connected to the high potential end and the negative pole is connected to the low potential end, the Schottky diode will conduct. This connection method is called forward bias. It must be noted that when the forward voltage applied to both ends of the Schottky diode is very small, the Schottky diode still cannot conduct, and the forward current flowing through the Schottky diode is very weak.

Only when the forward voltage reaches a certain value (this value is called "threshold voltage", which is about 0.2V for germanium tube and 0.6V for silicon tube), can the Schottky diode conduct directly. After conduction, the voltage at both ends of Schottky diode remains basically unchanged (about 0.3V for germanium tube and 0.7V for silicon tube), which is called "forward voltage drop" of Schottky diode.

Reverse characteristic In the electronic circuit, the positive pole of Schottky diode is connected to the low potential end and the negative pole is connected to the high potential end. At this time, there is almost no current flowing through the Schottky diode. At this time, the Schottky diode is in the cut-off state. This connection method is called reverse bias. When the Schottky diode is in reverse bias, there will still be a weak reverse current flowing through the Schottky diode, which is called leakage current. When the reverse voltage at both ends of the Schottky diode increases to a certain value, the reverse current will increase sharply, and the Schottky diode will lose its unidirectional conductivity. This state is called the breakdown of the Schottky diode.

The switching of forward and reverse characteristics in Schottky diodes forms the current conductivity of Schottky diodes. Under this kind of conductivity, Schottky diode makes better use of its own advantages to maximize the conductivity effect.