Working principle of transient suppression diode
Transient suppression diodes (transient voltage suppressor) (TVS) and working principle (also called zener diode voltage regulator diode), but there are differences on the structure. The biggest difference is generally composed of Zener diode PN junction area is very small, it can withstand the reverse current (reverse current is a diode switch in the specified temperature and the maximum reverse voltage, through the diode reverse current).
General small power regulator (0.5 ~ 1W) the maximum reverse current for tens to hundreds of Ma Ma; and transient suppression diode PN junction area is larger, the power dissipation can be larger, up to the maximum allowed reverse current several safety and security to tens. So it can absorb the instantaneous high voltage pulse caused by the instantaneous high current. General voltage regulator diode is 0.5 ~ 3W, while the transient diode up to 1500W, some for high pressure up to 10kW.
For example, a reverse breakdown voltage of Vbr is 6.4 ~ 7.3V, the power dissipation of 500W transient diode, it can withstand the maximum pulse current Ipp is 52 ~ 54A
A circuit (called a circuit), which is protected by a transient diode, is shown in the following figure, which is connected in parallel to the protection circuit. It should be noted that it does not require a current limiting resistor R. If the protected circuit operating voltage is +5V, then the optional 6.5 to 7V breakdown diode. In normal operation, the transient diode does not work quite open; when the operating voltage of the instantaneous pressure pulse, transient diode pulse moment was clamped around 9V in high voltage circuit, the moment 9V voltage on 5V work is safe. When the high voltage pulse in the past, the transient diode is quite open. It can be seen that in the power supply (the other forms of energy can be converted into electrical energy of the device is called the power supply) voltage is normal (or slight fluctuations) transient diode does not work, nor loss circuit. In a moment of high voltage pulse, it absorbs the instantaneous large current and clamped at a slightly higher than the work supply voltage protecting circuit. It can be used repeatedly, has a long service life.
This circuit can clamp on transient pulse, as can play a protective role in the positive and negative pulse, can be used the instant bidirectional diode, it is equivalent to two diodes in series with the reverse. Either positive or negative transient high voltage pulses can be protected, and the normal operation of the circuit is not affected.