A semiconductor switch and a temperature sensing circuit for such a switch.

摘要

A semiconductor switch has a power semiconductor device (1) and a temperature sensor (2) for providing a control signal to switch off the device (1) when it has a predetermined thermal condition. The power semiconductor device (1) comprises a semiconductor body (10) having a first region (13) of one conductivity type adjacent one major surface (10a) and a plurality of device cells (11) forming an insulated gate field effect device. Each cell (11) has a second region (32) of the opposite conductivity type provided within the first region (13), a third region (33) of the one conductivity type provided within the second region (32) and an insulated gate (34) overlying a conduction channel region (35) of the second region (32) for providing a gateable conductive path between the third and first regions (33 and 13). The temperature sensor (2) comprises a thermally responsive semiconductor device (100) formed within the semiconductor body (10) and comprising a number of further device cells (11') having the same structure as the power semiconductor device cells (11). The insulated gate (34) of each further device cell (11') is electrically connected to a third region (33) so that the further device cells (11') provide a parasitic bipolar (P) transistor having a leakage current which varies with temperature for enabling the temperature sensor (2) to provide the control signal to switch off the power semiconductor device (1) when the predetermined thermal condition exists. <IMAGE>