TVS diode is short Transient Voltage Suppressor. It is a form of high-performance diode protection device. Because of its excellent performance of the TVS tube quickly became popular, has become an important protection during an integral part of the electronics industry, it looks the same as ordinary diodes, but they absorb up to several kilowatts of power surge.
When TVS tube when subjected to high poles reverse transient energy shock, which can speed on the order of 10-12 seconds, it becomes high impedance between the poles of a low impedance, absorb up to several kilowatts of power surge, the poles voltage clamp located between a predetermined value, the effective protection of electronic circuits precision components, damage from various surge pulse.
Following on from Li Xin Electronics deep about each of the six skills of TVS tube selection for everyone:
1. The maximum peak pulse power: determining an interference pulse in the circuit, the interference pulse waveform, pulse duration, the determination can effectively suppress interference peak pulse power TVS diode.
2. TVS tube reverse displacement of the voltage, i.e. operating voltage (VRWM) - VRWM TVS selected tube operating voltage is greater than or equal to a predetermined step above. This ensures that the current absorbed TVS tube under normal operating conditions is negligible, if the voltage is higher than a predetermined step VRWM TVS tube, TVS diode will absorb a large amount of leakage current in the avalanche breakdown state, thus affecting the circuit work.
3. The protection circuit is determined to be a DC voltage or continuous operating voltage. If alternating current, calculate the maximum value, effective value * 1.414.
4. The selected maximum clamping voltage TVS tube (VC) should be lower than the maximum withstand voltage is allowed by the protection circuit.
5. If you know the more accurate inrush current IPP, you can use VC to determine its power, if you can not determine the approximate range of power, in general, choose power bigger is better.
6. unipolar or bipolar - is there such a misunderstanding often bidirectional TVS tube that is used to inhibit reverse surge pulse, in fact, not the case. A bidirectional TVS diode for alternating current applications or from the positive and negative bidirectional pulses.
TVS tube is sometimes used to reduce capacitance. If only the forward circuit level signal, then a unidirectional TVS diode is sufficient.
TVS diode operates as follows:
When forward surge, TVS tube in the reverse avalanche breakdown condition; reverse surge, TVS diode is forward biased as a similar tube conducting and absorbing surge energy. In the case of low capacitance in the circuit is not the case. TVS tube selection should choose a bidirectional TVS diode to protect the lower capacitor element circuits from reverse surge damage.