The transient pulse of the electromagnetic compatibility refers to the interference pulse of intermittence. It usually has higher disturbing voltage, more pulse rise time, wider spectral range. It usually includes electrostatic discharge (Electrostatic Discharge Simulator), electricity fast transient pulse group, and the surge impact and so on.
Since they have the above common characteristics, then there will be a bigger common ground in the judge of the test result and circuit suppression.
The common test result description of the transient pulse of flexibility test
Different test result can be classified into the following contents according to the working condition and functional specification of the product.
A：The normal function in the range of the technical requirement;
B：The temporary drop or loss of the function, but it can restore the performance by itself;
C：The temporary drop or loss of the function, it requires the operator intervention or system reset;
D：The unrecoverable function or loss caused by the damage of the equipment (component) or software, or the loss of the data.
If the product accords with A, the test result is qualified. It means that the product has the normal function in the entire test process, the performance index accords with the technical requirement.
If the product accords with B, the test result should take the product standard, product specifications or the provisions of the test program into consideration, when some influence is not important, it can be judged to be qualified.
If the product accords with C, the test result will not cause the damage except the special situation, most of the product will be judged to be unqualified.
If the product accords with D, it is judged to be unqualified.
B type or C type assessment should be written in the test report of the product accords with B and C.
The frequently used transient pulse inhibit circuit:
The ground-clamp diode protection circuit：
The objective of using two diodes is to restrain the transient voltage of both the positive and negative polarities. The transient voltage is champed in the range of V++VPN~V—VPN, the series resistor takes the power dissipation. The voltage range of the existing power is used as the shim range of the transient voltage. The positive guide electricity flow of the diode and the receptivity of the series resistor determine the protective ability of the circuit.
This circuit has superb protective result, at the same time; its cost is cheap, suitable for the situation of strict cost control, strong electrostatic discharge and unserious frequency.