Summary
International Symposium on Electromagnetic Compatibility
2014
Session Number:16A2-B
Session:
Number:16A2-B2
A Measurement on Electromagnetic Noises from ESD Generator just Before and After ESD Testing
Takeshi Ishida,
pp.-
Publication Date:2014/05/12
Online ISSN:2188-5079
Summary:
It is widely recognized that electrostatic discharge (ESD) generators cause electromagnetic (EM) noises even before and after ESD immunity testing specified in the International Electrotechnical Commission (IEC) standard. This may provide inconsistent test results, whereas its mechanism is not well understood. To explain the mechanism qualitatively, we investigated a generation modeling of EM noises from an ESD generator in conjunction with the functional sequences of built-in relay switches and a DC high voltage power supply. To validate this model, using a magnetic field probe, we measured the induced noise voltages from an ESD generator just before and after ESD testing for contact and air discharges to an IEC recommended current injection target. As a result, we confirmed that the EM noises are generated when the relay switches operate before and after ESD tests. In addition, we found that the noise amplitude for low voltage are relatively smaller than the ones induced at the testing in both the contact and air discharge modes, while these peak noises increase with charging voltages and especially the noise peaks induced after the testing almost reach the same level as the case for 4 kV ESD test in the air discharge mode. A new sequence of the built-in relay switch was also proposed for reducing the noise voltages generated after ESD testing.