Patent ID: 9562812
Date: 2017-02-07
CPC Classifications: G01K,H03K

Claim:
1. A temperature measuring device of a power semiconductor apparatus, the power semiconductor apparatus including a silicon chip with a power switching element and a temperature detecting diode thereon, the temperature measuring device detecting a chip temperature of the power switching element, the temperature measuring device comprising: a constant current source that supplies constant current to the temperature detecting diode, an A/D converter that outputs digital values representing forward voltage across the temperature detecting diode, an operational processing unit that calculates the chip temperature based on the digital values, the operational processing unit including a calibration processing section and a chip temperature calculating section, and a memory, a reference voltage source that successively generates a plurality of known reference voltages, a calibration processing section that selectively connects the reference voltage source to input terminals of the chip temperature calculating section and simultaneously disconnects the temperature detecting diode from the input terminals of the chip temperature calculating section, where the calibrating section calculates a gradient of a line segment connecting the digital values outputted from the A/D converter when the plurality of reference voltages are applied, wherein the gradient and an offset correction value of the digital values are stored in the memory, and wherein the chip temperature calculating section calculates the chip temperature according to a corrected value based on a measurement value of the digital values and also based on the gradient and the offset correction value.