Electromagnetic noise coupling and mitigation in dynamic tests of high power switching devices

During the dynamic test of high power switching devices, it can be challenging to measure both high speed and low amplitude signals accurately. This paper uses fast response on-die temperature sensing as an example to investigate the electromagnetic interference control of a typical double pulse test (DPT) setup. Three common noise sources are identified: 1) Conductive common-mode noise caused by multiple grounds, 2) Inductive coupled noise caused by capacitors with unbalanced cells, and 3) Inductive coupled noise caused by constant di/dt field during the device's conducting period. Their propagation paths are also identified and discussed in detail. Corresponding diagnosis and noise mitigation methods are proposed. Proposed mitigation methods do not have a negative impact on the differential impedance of measurement systems. Furthermore, a step-by-step noise identification and mitigation procedure is presented. General guidelines on the electromagnetic noise coupling control of DPT setups has also been summarized. It should be noted that even though this paper uses on-die temperature sensor measurement as an example, the identified noise coupling mechanism and proposed noise mitigation methods can be applied to most dynamic tests of high power switching devices.