Transient Voltage Suppressor (TVS) is a high performance protection device in the form of a diode. When the poles of the TVS diode are affected by the reverse transient high energy impact, it can change the high impedance between the poles into low impedance at a speed of 10 to the minus 12 seconds, absorbing up to several kilowatts of surge power, so that the voltage clamp between the poles is located at a predetermined value, effectively protecting the precision components in the electronic circuit from damage by various surge pulses.

Classification of transient voltage suppressors

According to the polarity, it is divided into unipolar and bipolar two types:

According to the use, it can be divided into general devices applicable to various circuits and special devices applicable to special circuits. Such as: all kinds of AC voltage protector, 4~200mA current environmental protection device, data line protector, coaxial cable protector, telephone protector, etc. According to the package and internal structure, it can be divided into: axial lead diode, dual in-line TVS array (suitable for multi-line protection), patch type, component type and high-power module type.

The selection technique of instantaneous voltage suppressor

1, determine the DC or continuous operating voltage of the protected circuit, the rated standard voltage of the circuit and the "high-end" tolerance.

2, TVS rated reverse turn-off VWM should be greater than or equal to the operating voltage of the protected circuit. If the selected VWM is too low, the device may enter the avalanche or affect the normal operation of the circuit because the reverse leakage current is too large. Serial connection sub-voltage, parallel connection sub-current.

3, TVS clamping voltage VC should be less than the damage voltage of the protected circuit.

4, in the specified pulse duration, the peak pulse power consumption of TVS PM must be greater than the peak pulse power that may occur in the protected circuit. After determining the clamping voltage, the peak pulse current should be greater than the transient surge current.

5, for the protection of the data interface circuit, we must also pay attention to the selection of TVS devices with appropriate capacitance C.

6, according to the use of TVS polarity and packaging structure. It is reasonable to choose bipolar TVS for AC circuit. TVS array is more advantageous for multi-line protection.

7, temperature consideration. Transient voltage suppressors can operate between -55 and +150 ° C. If TVS is required to work at a changing temperature, its reverse leakage current ID increases with the increase; The power consumption decreases with the increase of TVS junction temperature, from +25℃ to +175℃, and the rain breakdown voltage VBR decreases linearly by 50% with the increase of temperature according to a certain coefficient. Therefore, it is necessary to consult the relevant product information and consider the impact of temperature changes on its characteristics.