Transient voltage suppressor

We often hear the two abbreviations ESD and TVS, in fact, are two completely different concepts, some students are easy to confuse. ESD Quanpin is electrostatic discharge (ESD quanpin). It describes an objective phenomenon.

TVS is a transient voltage suppressor, which means "transient voltage suppressor" in Chinese. It is a high performance protection device in the form of a diode, which describes a device.

The relationship between ESD and TVS is that we use TVS to suppress the impact of ESD on electronic circuits, so as to ensure the normal operation of the circuit system.

TVS is connected in parallel with the protected device. Under normal conditions, TVS is the high impedance state of the signal. TVS provides a low impedance path when the instantaneous voltage is high enough.

ESD produces very high transient voltages for extremely short periods, sometimes up to a billionth of a second. If this high voltage is allowed to develop, it will cause serious damage to the circuit system.

TVS is generally used to absorb ESD energy, so as to protect the normal operation of the circuit system. The TVS symbol is shown below. TVS generally have two kinds of two-way and one-way. Generally, one-way TVS is used for DC circuits and two-way TVS is used for AC circuits.

TVS is a diode that is only used in reverse. It can be analogous to a Zener diode to clamp the voltage, and it can use the avalanche breakdown principle of the diode PN junction to prevent the high voltage from entering the low voltage circuit behind it.

The volt-ampere characteristic curve of unidirectional TVS is very close to the volt-ampere characteristic curve of diode. We use its negative working area and the IV characteristic curve of bidirectional TVS, which is the symmetry of the unidirectional TVS working area curve, which can inhibit bidirectional static electricity.

The above is a basic introduction to ESD and TVS. The next article will take unidirectional TVS as an example to detail the significance of TVS parameters, which will help to select the right TVS in the actual circuit and effectively inhibit ESD.

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