What is a freewheeling diode, its structure, principle, function, type, operating procedures, and development history

A freewheeling diode is a semiconductor device with bidirectional conductivity, also known as a capacitor diode or a forward and reverse parallel thyristor. It is usually used in parallel with AT24C04BN-SH-T switch tubes or other power devices in circuits to eliminate reverse high-energy pulses and prevent reverse breakdown, thereby improving the stability and reliability of the system. Its main function is to provide a controllable conduction path in AC circuits to achieve precise control of current. The following is a detailed explanation about the freewheeling diode:

1、 Structure:

The structure of a freewheeling diode is similar to that of a regular diode, mainly composed of P-type and N-type semiconductors connected by a PN junction, but its special design allows it to withstand reverse high voltage. They are generally made of silicon materials because silicon diodes have high withstand voltage and low forward voltage drop.

2、 Principle:

The working principle of a freewheeling diode is based on the unidirectional conductivity of a PN junction. When operating an inductive load, the freewheeling diode is connected in reverse parallel at both ends of the load. When the circuit is powered on, the freewheeling diode is in a reverse cutoff state, which does not affect the normal operation of the circuit; When the circuit is disconnected, the high reverse voltage released by the inductor causes the freewheeling diode to quickly turn on, forming a circuit that safely releases the current released by the inductor, thereby protecting the circuit from damage.

3、 Function:

Continuous current diodes can be used as auxiliary components for overvoltage protection, energy recovery, and resonant circuits, and are widely used in the field of power electronics.

4、 Type:

Freewheeling diodes can be classified according to different standards, such as silicon diodes, Schottky diodes, etc., based on their materials; According to the withstand voltage level, it can be divided into low voltage, medium voltage, and high voltage freewheeling diodes; According to the packaging form, it can be divided into various types such as surface mount (SMD) and direct insertion (DIP).

5、 Operating procedures:

The correct operation of the freewheeling diode is crucial for ensuring the safe and stable operation of the circuit. The following are the basic procedures for operating a freewheeling diode:

1. Installation: When installing a freewheeling diode, attention should be paid to the connection direction of its positive and negative poles. Proper connection can ensure its normal operation and avoid damaging components due to reverse connection.

2. Working conditions: The freewheeling diode should operate within the specified operating voltage and current range, as exceeding these ranges may result in component damage. In addition, it should be avoided to use in high temperature or humid environments to ensure its performance and lifespan.

3. Thermal design: When designing circuits, the thermal design of freewheeling diodes should be considered to ensure effective heat dissipation. Excessive temperature can affect the reliability and performance of components.

4. Insulation protection: To avoid external damage or dust pollution to the freewheeling diode, it is recommended to install appropriate insulation protection measures during use, such as a casing or casing cover.

5. Precautions: When operating the freewheeling diode, avoid overloading or short circuiting, promptly handle any abnormal situations that may occur in the circuit, and avoid damaging the freewheeling diode.

6、 Development history:

A freewheeling diode, also known as a Schottky diode, is a special type of diode with low turn-on voltage and high withstand voltage, commonly used in power circuits and power electronic devices. Its development process can be traced back to the 1920s.

The earliest freewheeling diode was the metal semiconductor contact diode invented by German physicist Wolfgang Schott in 1914. Subsequently, in 1941, scientist M.S. Fowler utilized semiconductor materials to fabricate large-area P-N contact diodes, pioneering the research direction of modern freewheeling diodes.

In the 1950s, with the rapid development of semiconductor technology, the field of power electronic devices began to receive more attention. In the 1960s, freewheeling diodes gradually became popular and applied in various circuits, and their structure and performance were gradually improved and optimized. In the 1980s, with the increasing demand for power semiconductor devices, the research on freewheeling diodes entered a rapid development stage, and many new and high-performance freewheeling diode products emerged.

In recent years, with the continuous expansion of the application field of power semiconductor devices and the continuous progress of technology, freewheeling diodes, as one of the important power electronic devices, are still being researched and improved to meet the requirements of higher power, higher frequency, and higher reliability. In fields such as power electronics, automotive electronics, and industrial control, freewheeling diodes will continue to play an important role.

I hope the above content can help you better understand freewheeling diodes and their related knowledge