Low-cost temperature sensors in CMOS technology

Abstract

Temperature greatly affects the performance of integrated circuits, and so temperature sensors are often necessary to ensure reliable operation and stable performance. The goal of the work described in this thesis is to realize a temperature sensor in CMOS technology that can be produced at low cost. In the first step, a temperature sensor is developed that, unlike its predecessors, does not require individual batch calibration, thus significantly reducing calibration costs. In the second step, low-cost calibration methods are developed to calibrate the sensor at two different temperatures: room temperature and an elevated temperature created by an on-chip heater. These calibration methods are used to correct the shifts in the sensor's output caused by the mechanical stress of plastic packaging or to maintain the sensor's accuracy over a wide temperature range. In the final step, additional functionality is added to the sensor to measure external capacitances and voltages. This is achieved by reusing the circuitry of the temperature sensor, thereby making a cost-effective use of its area.