Patent ID: 8596864
Filing Date: 2013-12-03
Classification: G01K

Abstract:
1. A digital output temperature sensor comprising: a first circuit configured to generate a first signal; a second circuit configured to generate a proportional to absolute temperature (PTAT) voltage signal, the first circuit comprising: i) a PTAT current control reference voltage generating circuit configured to generate a PTAT current control reference voltage signal; ii) a digital to analog converter circuit including a plurality of current sources receiving the PTAT current control reference voltage signal and being selectively switchable between a conductive state and a non-conductive state and including current source transistors having lengths, widths or lengths and widths, that are varied in size between opposite ends of the digital to analog converter circuit thereby providing linearity of the digital to analog converter circuit over a range of temperatures of the sensor, wherein each of the plurality of current sources in the conductive state sources a partial current; iii) a current summing junction summing each of the plurality of partial currents as a PTAT current signal; and iv) a resistor between the current summing junction and a ground, the resistor being configured to convert the PTAT current signal to the PTAT voltage signal; a comparator operatively associated with the first and second circuits and configured to receive the first signal and the PTAT voltage signal and generate a comparison signal based on a comparison between the first signal and the PTAT voltage signal; and, a converter circuit operatively associated with the comparator and configured to receive the comparison signal and generate a digital output signal based on the comparison signal, the digital output signal being representative of the temperature of the sensor; wherein the first circuit is a reference voltage generator circuit including a single series diode configured to generate a complementary to absolute temperature (CTAT) voltage signal as the first signal; wherein the converter circuit is configured to receive the comparison signal and generate the digital output signal proportional to the temperature of the sensor.