2023-01-31
Transient suppression diode referred to as TVS, also known as clamping diode, is composed of P-N junction area, can be divided into one-way TVS tube and two-way TVS tube, one-way has a positive and negative electrode, two-way has no positive and negative electrode. TVS is widely used in the protection of semiconductors and sensitive devices, usually used for the protection of secondary power supplies and signal circuits, as well as anti-static. It is characterized by fast reaction speed (ps class), small size, large pulse power and low clamping voltage. Li Yang Electronics technicians and you talk about the role of transient suppression diode, working principle and the application of transient suppression diode.
A, transient suppression diode action
1. The TVS diode is added to the signal and power line, which can prevent the microprocessor or single-chip computer from failing due to instantaneous pulse, such as electrostatic discharge effect, AC power surge and noise caused by switching power supply.
2. Electrostatic discharge effect can release more than 10000V, 60A pulse, and can last 10ms; The general TTL device, when encountered more than 30ms of 10V pulse, will lead to damage. With TVS diodes, the pulse that can cause device damage can be effectively absorbed and interference caused by switching between buses can be eliminated (Crosstalk).
3. The TVS diode is placed in the signal line and ground, which can avoid unnecessary noise impact on the data and control bus.
Second, the working principle of transient suppression diode
TVS diode in parallel in the circuit, when the circuit is working normally, it is in the cutoff state (high resistance state), does not affect the normal operation of the line, when the circuit appears abnormal overvoltage and reaches its breakdown voltage, it quickly changes from a high resistance state to a low resistance state, to provide a low impedance conduction path for the instant current, while clamping the abnormal high voltage in a safe level. Thereby protecting the protected IC or line; When the abnormal overvoltage disappears, it returns to the high resistance state and the circuit works normally.
Third, the application of transient suppression diode
1, the application of AC circuit
The dual transient suppression diode 12v device is connected in parallel at the output end of the power grid, so that the overload pulse of the power grid can be greatly suppressed, and the safety and reliability of the rectifier bridge and the dynamic parts in the load can be improved indirectly in the actual application process. The registration voltage is smaller than the circuit voltage limit.
2, in the application of direct current circuit
The series of transient suppression diodes in the power line, the state is one-way, and the number is two, so it can avoid the problem of reverse connection of the DC power supply, or the instantaneous pulse in the process of power on and off, which leads to serious loss failures in the integrated circuit. If the circuit is connected to a device with an inductive load, a relatively high transient pulse voltage will be formed.
3, the application in microcomputer
Transient suppression diode is a microcomputer system, mainly by the power line, input line, output line composed of interference or transient voltage, resulting in a relatively high probability of computer misoperation problems, especially the power switch, the microcomputer near the motor to open and close, etc., have a great opportunity to make the system serious failure failure. The transient voltage suppression diode can complete the operation of the microcomputer power line, input and output lines, so that the operation of the microcomputer can be guaranteed, and the value and reliability of practical application can be improved.
