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How to determine and carry out the EMC test of the switching power adapter? It should be implemented according to a set of procedures. Today, the power adapter manufacturers share the EMC test with the following steps.
1. Switching power adapter EMC develops a test program and test details.
The test program is usually formulated by the user. The test requirements are based on the nature, purpose, and classification of the tested power adapter. The test level, the test range (such as frequency band, field strength, etc.), the standard used, and the number of parts to be tested are determined. , the status of work, methods of sensitivity monitoring, etc., to guide the conduct and design of the test, write test details, and also as archived information.
The test rules are usually prepared by the tester. According to the information given by the test plan of the testee and the proposed test items, the test is arranged. Starting from the non-destructive conducted emission and radiation emission test, the power cord needs to be processed or stripped. Immunity test items that may cause failure due to interference may be placed at the end. For small-scale tests, only a single instrument or a bottom test can be performed. There is no need to do a number of test details (for example, according to the standard), but the above arrangement still exists.
2. Determine the criteria on which to base.
The switching power adapter EMC test can be carried out according to the classification of the product according to the corresponding test standard. The test standard contains two aspects: one is the test requirement, which gives the limit value that the switching power adapter must meet or meet; the second is the test method. , specifies uniform measurement instrument specifications and test layout and test procedures.
3. Exchange test interface information.
The tested switching power adapter enters the laboratory. The arrangement of the instrument, the access of the monitoring equipment, and the connection of the power supply must be arranged and prepared in advance, especially the length of some connecting cables, such as the connected parts connected to the monitoring equipment. The cable must be specially considered. To have sufficient length, the power cord for conducting the test should be sorted out from the cable bundle, otherwise the correct test arrangement cannot be performed.
4. Check the measuring instrument.
Before the formal test, the measurement system should be connected and functionally checked to ensure that the measuring instruments are working properly, the test connection is error-free, and the test uncertainty is within the allowable range. This step can be used as a regular inspection item or according to the standard requirements. Execute before each test.
5. Start the subtest
The test allows different DUTs and different test items to cross. For example, for the same switching power adapter, after testing all the items, test the next switching power adapter, but the test conditions of the same project must be guaranteed. When using this method, the workload of the tester is large. For each test, a system needs to be changed, which is suitable for the case where the tested component is large and difficult to move. It can also be tested according to the sequence of test items. After the piece, replace the next item. Some tests can be measured simultaneously with several parts to be tested, such as radiation immunity test, as long as the measured part is not very large and has the means of simultaneous monitoring. The specific test sequence is negotiated by both parties.
6. Issue test report
After the test is completed, the recorded test conditions, the working parameters of the tested parts, and other data and curves are sorted and classified according to the parts to be tested and the items are judged, which are passed, which switching power supply adapters are not passed, the conditions and status of the failure are passed, and the sensitive The threshold or threshold level, the frequency or amplitude of the conduction or radiation emission test exceeding the limit value, analyze and give the test results of the switching power adapter, and form a test report.