Transient interference voltages and currents are the main cause of damage to electronic circuits and equipment , and often gave rise to incalculable loss . Start-stop operation of these interference from electrical equipment are usually unstable AC power grid , lightning interference and electrostatic discharge , transient interference almost everywhere and at all times there , people feel very hard to detect . Fortunately , an efficient circuit protection devices appear TVS tube can make transient interference has been effectively suppressed TVS tube or called transient voltage suppression diodes are developed on the basis of the regulator process of a new product , its circuit symbol same diode voltage regulator and the general shape is also no different from ordinary diodes , TVS tube at both ends when subjected to transient high-energy impact , it at very high speed ( up to 1 * 10-12 seconds ) it suddenly reduced impedance while absorbing a large current , the voltage between both ends of the clamp at a predetermined value , thereby ensuring that the back of the circuit elements from transient high-energy impact damage. If you are using the words , TVS diode type, and varistors classes. I personally think varistor class advantage , now widely used in mobile phones , LCD modules, and some of the more sophisticated handheld devices. Especially export products are generally required to increase Europe , as one of the primary means of ESD protection.
TVS tube and zener voltage regulator can be used , but the TVS tube Zener breakdown current is smaller, greater than 10V regulator only 1mA, relatively speaking, the zener diode breakdown current to a large lot, but Sarkozy Zener diode voltage regulator can be done relatively high accuracy .
In the circuit generally work in reverse off, at which point it does not affect any function of the circuit . TVS tube in reverse when the conditions specified in the application , when the circuit due to lightning , various electrical interference or substantial interference voltage transient pulse current , which in a very short period of time ( up to reach 1 × 10-12 s ) quickly transferred reverse conduction state , the voltage clamp circuit on the safety and value required to effectively protect electronic circuits precision components from damage. After the interference pulses in the past , TVS tube into reverse and off-state . Since the reverse-conducting , the clamping voltage is below the maximum pressure in the other circuit devices , and therefore play a protective role in other components . TVS tube can withstand instantaneous pulse power up the kilowatts , the clamp time is only 1ps. TVS tube can be divided according to the polarity of unidirectional and bidirectional TVS tube . Unidirectional TVS tube is generally applicable to the DC circuit , bidirectional TVS tube are generally applicable to AC circuits . Since TVS protective effect when the tube moves quickly , long life, easy to use, and therefore transient voltage protection in the field has a very wide range of applications .
The parameters are described as follows :
1 , the breakdown voltage V (BR)
2, the maximum reverse pulse peak current Ippm
3, the maximum reverse voltage VRWM
4, the maximum clamping voltage VC (max)
5 , the inverse pulse peak power Pppm
6 , capacitive CPP
7 , the leakage current IR