Schottky diodes have several common and important currents

Schottky diodes have several common and important currents

In actual engineering practice, Schottky diodes  are often used in AC voltage conversion circuits, and are often used to stabilize circuits, limiting circuits, freewheeling circuits, and select several common and important currents to analyze.

1. It plays a freewheeling role in the inductance of the switching power supply and in the inductive load such as relay, which is very practical.

Switch A and Switch B are implemented using PFET and NFET switches, respectively, to form a synchronous buck regulator. The term "synchronous" indicates that a FET is used as a low-side switch. Buck regulators that replace low-side switches with Schottky diodes  are called "asynchronous" (or asynchronous) types. When dealing with low powers, synchronous buck regulators are more efficient because the voltage drop of the FET is lower than that of a Schottky diode, which is primarily determined by Rds(on). However, when the inductor current reaches 0, if the bottom FET is not released, the light load efficiency of the synchronous converter is reduced, and additional control circuitry increases the complexity and cost of the IC. Schottky diodes can be used as freewheeling diodes, Schottky's PN junction is special, which makes it have a very small junction capacitance and little stored charge, so this junction has a very fast switching speed and can be used for high-speed embedding. Schottky diodes feature very fast switching speeds and particularly short reverse recovery times. Therefore, switching diodes can be made of low-voltage high-current rectifier diodes.

2. Analog water flow simulation of Schottky diode action

Voltage is often compared to water pressure, and the function of a Schottky diode can be simulated similarly to water flow. The Schottky diode relative current is like a one-way valve, when forward biased, as long as the bias voltage exceeds the threshold voltage, the valve will open and the water flow can flow down smoothly; For reverse bias, the valve cannot be opened and no water flows through.

3. Schottky rectifier diode

Using the unidirectional conductivity of Schottky diodes , alternating alternating current in alternating direction can be converted into pulsating direct current in a single direction.