Recently, lamp customers have new EMC needs, the electromagnetic iron of far and near light switching needs to test the 5B waveform of 7637, many mature products are taken to test, the TVS protection diode of the input port is burned out, engineers find many reasons, find Leiditech electronic discussion solution.

Leiditech Electronics carefully analyzed the product structure and circuit, electromagnetic iron itself is a circuit structure without IC, equivalent to an inductor, any high voltage, will not be damaged, but in the earliest design of Japanese models or in the front end of the circuit added protection devices, generally plug-in or patch two. As shown in the picture is the earliest plug-in protection protection design, this scheme is simple, no PCB board is required, but the assembly labor cost is high, the latest version is a chip device, which greatly improves assembly efficiency and reduces costs: 

 When doing EMC testing in the Leiditech Electronics Laboratory, the protective diode is indeed removed, the entire electromagnetic iron will not be broken, the test is normal, but the engineer ignores a problem, since it is an inductor, he will have energy storage, each waveform test is completed, the reverse output voltage of the transmitting voltage end, and the longer the waveform time, after the oscilloscope waveform grabbing found that this energy is very large, in the car, the click on the output voltage is a great damage, so the whole lamp module for this test requirement is necessary.

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       After customer supply, Xingyu, Koito, Passat, Q5, Roewe 750 series and other different 7637-5B needs of various car manufacturers, different design verification, the selection of Leiditech Electronics 5.0SMDJ series of automotive grade TVS to meet the test needs.