Current-sensing power MOSFETs with excellent temperature characteristics

For MOSFETs with a current-sensing function (current-sensing power MOSFETs), temperature-based changes in the current sense ratio have been a significant problem. This research clarified the mechanisms involved in these temperature-based sense ratio changes and identified the effects of the following on sense ratio temperature dependence: (1) Drift layer impurity concentration and layer thickness, and (2) The position of the sense MOSFET part in the chip. Furthermore, by adopting a FITMOS structure, it was shown that temperature-based changes in the sense ratio could be reduced from 11.2% to 3.4%.