Full-frame infrared thermal imaging of power electronics devices by means of multiple time-delayed measurements

The paper presents a method for mapping the temperature distribution of very fast transient events (i.e. having a bandwidth of 10 kHz or more) by means of a standard infrared camera working at 25 Hz frame rate with 320 × 256 pixels full frame. The proposed method is based on triggering multiple time-delayed acquisitions of the observed thermal phenomenon, which must be periodic, by means of a very precise and stable programmable digital micro-controller and by reconstructing the time domain IR sequence using the frames acquired at each trigger event. The measurement accuracy of the reconstruction process has been assessed by using a laser-cut planar resistor cyclically heated by means of a pulsed electrical current. A practical application to investigate the temperature distribution over the source metal of a power MOSFET device is finally presented.