digital temperature sensor，现在用的多吗？

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Conventional temperature sensorsuse voltage-based analog sensors. Bipolar JunctionTransistor (BJT)-based analog sensors use a precise trimmingprocedure to achieve high accuracy, but have a complex architecture and large area, because analog sensors need to convertproportional to absolute temperature (PTAT) voltage to digitalcode using an analog-to-digital converter (ADC). To overcomethe shortcomings of analog sensors, simple digital temperaturesensors, with their advantages of low power and small area,have been presented. Digital temperature sensors,using digital logic circuits such as inverters or NAND chains,generate a pulse, the width of which varies according to temperature variations, and the generated PTAT time pulse is converted into a digital code by a time-to-digital converter (TDC)to indicate the temperature. In addition to the temperaturevariations, however, process variations also have impacts onthe pulse width. These process variations degrade the measurement accuracy. Thus, for accurate temperature measurement, it is very important to eliminate process variations indigital-based temperature sensors. Previously presented digital temperature sensors perform the calibration for processvariations outside the chip. However, the external processvariation calibration is time-consuming and thus has a highcost. To reduce the calibration cost, recently proposed digitaltemperature sensors embed the calibrationcircuits and perform 1- or 2-point calibration inside the chip.