Patent ID: 6052268
Filing Date: 2000-04-18
Classification: H01L,H03K

Abstract:
Electrical apparatus including a semiconductor switching device (30), an arrangement (4, 5, 9, 15) that derives a measure of power dissipated by said device, a sensor (10) that provides a measure of the temperature in the vicinity of the device, and means to restrict flow of current through the device (3) in response to a combination of the measure of power and the measure of temperature, characterised in that the apparatus includes a processor (15) that calculates the resultant heat gain and heat loss of the semiconductor device (30) over a period of time at a plurality of different nodes within the device (30), that the processor (15) calculates the temperature of the device at a plurality of different nodes in the device at the end of that time, and that the apparatus restricts flow of current through the device if the calculated temperature of the node with the highest calculated temperature exceeds a predetermined temperature.