A High Accuracy Temperature Sensor and Temperature Compensation Algorithm Embedded In TPMS

A high accuracy temperature sensor integrated in TPMS with an inaccuracy of +/-1 degrees C from -55 degrees C to 125 degrees C is realized in a standard CMOS process. The errors due to finite op-amp gain, offset voltage and 1/f noise are eliminated with correlated double sampling technique. The temperature-dependent voltage is boosted by a switched capacitor low noise amplifier and digitalized with an incremental ADC of a resolution about 13 bits. Furthermore, 2-bits coarse biased current trimming and 5-bits fine resistive-array trimming are applied to calibrate the process variation. The required accuracy is obtained after the calibration at single temperature point. Additionally, the second-order nonlinearity temperature compensation algorithm for piezoresistive pressure sensor is described. Finally, experimental results are provided to verify the effectiveness of the proposed topology.