Transient suppression diode is also known as the TVS diode, the reverse application of prescribed conditions when subjected to a transient overvoltage of high energy pulse, the impedance immediately dropped very low turn-on value, allowing high current through and voltage clamp to a predetermined level, so as to effectively protect the precision components in electronic circuit from damage. So TVS diode applied to switch power supply should be how the ratio is better? What are the typical components to be protected in the power supply? Today from the electronic technology in this small series for you about the TVS diode used in switching power supply case.
TVS diode can withstand instantaneous pulse power can reach a kW, its response time is only 1ps (10-12S) clamp. TVS diode allows the forward surge current at TA = T, 250C = 10ms, up to 50 ~ 200A. Bidirectional TVS diode can absorb large instantaneous pulse power in two positive and negative direction, and the voltage clamped to a predetermined level, bidirectional TVS diodes for AC circuit, one-way TVS diode generally used for DC circuit. One, TVS diode protection switching power supply example:
For switching power supply designers, it is necessary to protect the three transient types that affect the beginning of the power supply:
1, transient voltage caused by load change (inductive load);
2, by the introduction of the power line transient voltage;
3, by the switching power supply internal transient voltage.
Due to the need to protect the power of the typical components are:
1, high reverse voltage switching transistor (VMOS tube)
2, high voltage rectifier (high voltage rectifier diode)
3, output rectifier (high current output rectifier diode)
4, internal control circuit (pulse width modulator, etc.)
Two, TVS diode with PTC for LED wash wall lamp lightning protection case:
Application of a PTC self recovery fuse with a 6.8V or TVS 7.5V diode can achieve a very good lightning protection purposes, the original RS485 interface is 5V, the current is more than a dozen Ma, so it is very easy to damage.
Wall lamp installed in the installation of the wrong line is easy to connect to the 220V, there is a short circuit, the need for lightning protection and so on. Self recovery fuse series to RS485 AB line, room temperature resistance is small; the TVS diode is connected in parallel to the AB line, generally not conducted, when a lightning current, short circuit, fault from 220V line will have high voltage and high current, high voltage when TVS trigger tube conduction by large current after the self recovery fuse, the self recovery fuse device capable of quick action from the state of low resistance mutation to a high resistance state, thereby limiting the current limiting protection, do the RS485 of the circuit system, eliminate power failure or failure, self recovery fuse will automatically return to the low resistance state, LED wash wall lamp circuit to resume normal work. If there is no self recovery fuse element is constant heavy current quickly burn out TVS diode, so it is with the self recovery fuse protection system to achieve the purpose of protection diode TVS.
The above content by providing professional technology department of Shenzhen science and Technology Co., Ltd. tage! By 20 years of experience in electronic technology from duct strict prepared, after the company‘s official website on the appropriate reviewers. From the electronic is more TVS diode for the company‘s core products, welcome to buy!