Design of an integrated temperature and humidity sensor based on high dynamic range utilization rate ADC

An integrated sensor for temperature (Temp) and humidity (RH) measurement is designed. The temperature and humidity (T/H) sensing probe are combined with one first-order discrete-time Sigma-Delta analog-to-digital converter (ADC). Also, a new ample architecture of ADC is proposed, ADC selects a reasonable reference voltage according to varied range of T/H signals. Therefore, the dynamic range utilization rate of ADC is improved. The proposed sensor is designed and fabricated in 0.153 mu m CMOS technology. The experimental results show that the T/H sensor achieves a -0.9 similar to 0.6% RH measurement accuracy in the humidity range of 10 similar to 90% RH, and +/- 0.4 degrees C temperature measurement accuracy in the temperature range of -40 similar to 120 degrees C