What is a switching diode? The basic structure, characteristics, working principle, types, operating procedures, common problems, and development history of switching diodes

Switching diode is an M95040-WMN6TP electronic component used to control the flow of current. It has fast switching speed and small switching losses, can operate at high frequencies, and is widely used in power supplies, communications, computers, and various electronic devices.

1、 Basic structure:

Switching diodes are composed of two semiconductor materials, one is a P-type semiconductor and the other is an N-type semiconductor. Among them, impurities in P-type semiconductors contain positive charges called holes, while impurities in N-type semiconductors contain negative charges called electrons. Two semiconductor materials are combined together through a PN junction to form the basic structure of a switching diode.

2、 Characteristics:

1. Fast switching speed: The switching speed of the switching diode is very fast, capable of completing switching operations in nanoseconds.

2. Low switching loss: Due to the absence of an emitter in the switching diode, its switching loss is relatively small, which can effectively reduce energy consumption.

3. High frequency operation: Switching diodes can operate at high frequencies and are suitable for controlling high-frequency circuits.

4. High reliability: Switching diodes have a long service life and high reliability.

3、 Working principle:

The working principle of switch diodes is based on the characteristics of PN junctions. When forward biased, current can pass through the PN junction and form a conducting state; When reverse biased, the PN junction will generate a depletion region, preventing current from passing through and forming a cutoff state. By controlling the variation of forward or reverse bias voltage, the control of switching diodes can be achieved.

4、 Type:

According to different application requirements, switch diodes can be divided into different types:

1. Ordinary switch diode: has low voltage and current carrying capacity, suitable for low voltage and low current applications.

2. Rectification type switch diode: It has high voltage and current bearing capacity and is suitable for high voltage and high current rectification circuits.

3. Reverse switching diode: It has a special structural design that allows it to only conduct under reverse voltage, making it suitable for specific application scenarios.

4. Enhanced Switching Diode: Optimized design based on ordinary switching diodes, with higher voltage tolerance, current tolerance, and switching speed.

5、 Operating procedures:

1. Firstly, confirm the positive and negative terminals of the switch diode. Generally speaking, the positive pole of a switching diode is labeled as the anode (Anode), and the negative pole is labeled as the cathode (Cathode). Ensure proper connection.

2. Before operation, disconnect the power supply to ensure safety. Connect the switch diode to the circuit as needed. Generally speaking, the anode is connected to the positive pole of the power supply, and the cathode is connected to the negative pole.

3. After connecting the power supply, the switch diode is controlled through an external circuit. The control method can be through the control of switches, level signals, or other components.

4. When the control signal arrives, the switch diode is in a conducting state. At this point, current can flow from the anode to the cathode, and the voltage drop is relatively low.

5. When the control signal is disconnected, the switch diode is in the off state. At this point, the current cannot pass through the diode and the voltage drop is high. When it is necessary to change the state of the switching diode, simply change the state of the control signal.

6. During operation, attention should be paid to voltage and current limitations to avoid exceeding the rated value of the switching diode, in order to prevent damage to components or circuit failures.

7. After the operation is completed, the power should be disconnected to prevent the current from continuing to flow.

6、 Common problems:

1. Current cannot flow: If current cannot pass through the switch diode, it may be due to reverse polarity connection or damage to the switch diode. Firstly, ensure that the polarity is correctly connected, that is, the anode is connected to the positive electrode and the cathode is connected to the negative electrode. If the connection is correct but the current still cannot flow, it may be a damaged switch diode that needs to be replaced.

2. Leakage current is large: In the cut-off state, the switching diode should block the current. If the leakage current is large, it may be caused by excessive reverse voltage. Check if the voltage in the circuit exceeds the rated value of the switching diode. If so, appropriate voltage limiting measures need to be taken, such as adding reverse voltage protection circuits.

3. High temperature: During operation, the switching diode may generate a certain amount of heat. But if the temperature is too high, it may be due to excessive current or prolonged operation. Check if the current exceeds the rated value of the switch diode and adjust the circuit design or reduce the current appropriately.

4. Short lifespan: The lifespan of switch diodes is affected by factors such as operating conditions and current load. If the lifespan of a switching diode is short, it may be due to high operating temperatures, excessive current, or exceeding the rated pressure of the component. In the design and use process, it is necessary to choose switch diodes reasonably, avoid exceeding their rated parameters, and ensure that the working conditions comply with specifications.

5. Reverse breakdown: Switching diodes may experience breakdown when the reverse voltage is too high, resulting in component damage. To avoid this situation, it is necessary to design the circuit reasonably and add appropriate reverse voltage protection measures, such as diodes, voltage regulators, etc.

7、 Development history:

A diode is the simplest semiconductor device that has the characteristic of allowing only unidirectional current to pass through. Its development process can be traced back to the early 20th century. With the development of electronic technology, switch diodes are gradually being widely used in various fields. With the advancement of semiconductor technology, the performance of switching diodes continues to improve, and new types of switching diodes such as fast recovery diodes and Schottky diodes have emerged.

In 1904, American scientist John Fleming discovered the phenomenon of hot electron emission, where electrons are emitted from a hot cathode to an anode. This laid the foundation for the development of diodes.

In 1906, British scientist Lee DeForest designed the first true diode, the vacuum diode. It consists of a hot cathode and a positively charged anode, which can achieve unidirectional conduction of current.

In 1947, Shockley and Bardeen from Bell Laboratories in the United States discovered the semiconductor diode effect, known as the PN junction diode. This has brought revolutionary changes to the development of diodes. A PN junction diode is composed of a P-type semiconductor and an N-type semiconductor, which can achieve more efficient current control.

In the 1950s, German scientist Hermann Schottky invented the metal semiconductor contact diode, also known as the Schottky diode. It is made of gold and has a lower turn-on voltage and faster switching speed compared to semiconductor materials.

Since the development of modern diode technology, various types of diodes have emerged, such as fast recovery diodes, Schottky barrier diodes, light-emitting diodes, etc. These diodes have been widely used in the field of electronics, driving the development of modern electronic technology. At present, switch diodes have become an indispensable component in electronic devices, making significant contributions to the development of modern technology.