一种工艺误差校准的低功耗温度传感器

A Low Power Temperature Sensor with Process Error Calibration

采用一种新的张弛振荡器,实现了一种不受工艺影响的低功耗片上温度传感器。将与温度成正比的电流输入到振荡器,产生与温度成正比的频率,再利用计数器来实现频率到数字的转换。振荡器通过数字逻辑产生两种模式,分别控制受温度控制的振荡器(TDO)和对温度不敏感的振荡器(TIO),这两种模式只需1个振荡器和1个计数器,减小了面积和功耗。采取工艺粗校准和工艺精校准两步校准,减小了工艺偏差。实验结果表明,经过两步校准后,在-40℃到120℃范围内,温度传感器的分辨率为0.08℃/LSB,温度传感器的最大误差为+0.35℃/-0.6℃。在1.2 V电源电压、120℃温度的条件下,电路总功耗仅为23μW。

A process independent low power on-chip temperature sensor was proposed on the basis of a novel relaxation oscillator.A proportional to absolute temperature(PTAT)current was applied to the relaxation oscillator to get a PTAT frequency.A counter was used to transfer the frequency signal to the digital signal.This circuit used digital logic to get two modes of the oscillator,which could control the temperature dependent oscillator(TDO)and the temperature independent oscillator(TIO)respectively.Only one oscillator and one counter realized the two modes to save the circuit’s area and power dissipation.Two steps of coarse process calibration and fine process calibration were used to minimize the impact of the process variation.Experiment results showed that,in the range from-40℃to 120℃,the temperature sensor had a resolution of 0.08℃/LSB and a maximum error of+0.35℃/-0.6℃after two calibration steps.It dissipated 23μW at 120℃with a power supply of 1.2 V.