TVS (transient suppression Diode) can effectively protect the circuit from transient surge voltage and current. But once it is broken down, what are the possible phenomena?

Transient suppression diode TVS and voltage regulator diode, ESD electrostatic diode, GDT discharge tube, TSS discharge tube, varistor and other electronic components are several kinds of overvoltage protection devices used in electronic circuit protection nowadays, and their applications are very wide.

Today, we're going to talk about TVS tubes. It is a kind of surge suppressor, which can change from high impedance to low impedance in a very short time, absorb surge current, clamp the voltage at both ends within a safe level, and achieve the function of protection circuit. therefore, it has the advantages of fast response, low leakage current and high transient voltage power. its flow rate belongs to one of the lower overvoltage protection devices mentioned above and is often used as the final protection of the circuit. For example: the power supply lightning protection, with varistor or GDT ceramic gas discharge tube to use together.

When the TVS tube is broken down, there are three possible failure modes:

1. Once the transient surge current exceeds the energy that the device itself can bear, it may cause overpower damage to the TVS transistor and, in serious cases, burn out. This failure mode is a short circuit.

2. If the flow rate of the TVS transistor is small, and the current passing through the circuit is large, it will also cause the device to burst, and this failure mode is open circuit.

3. There is another kind of performance degradation, the use frequency of the device is too high, resulting in changes in the internal structure, the decline of heat dissipation capacity, resulting in component failure, this mode is also a short circuit.

No matter which failure mode it is, in practical use, the failure mode of TVS transient suppression diode is caused by comprehensive factors. We should consider these when selecting the device, choose the type that matches it, and take precautions against it.