High-Sensitivity PTAT Current Generator Using PTAT and CTAT Current Subtraction Method for Temperature Sensor With Frequency Output
Tzung-Je Lee, Kuo-Hsun Tu · IEEE Transactions on Circuits & Systems II Express Briefs · 2023
This design proposes a wide dynamic range temperature sensor. With the proposed novel high-sensitivity PTAT current generator, the current sensitivity to temperature is improved from 12.9 nA/°C to 192 nA/°C by using the subtraction of PTAT and CTAT currents. It results in the sensitivity improvement of 14.89 times. The high sensitivity PTAT current is then converted into the output frequency by the voltage-to-frequency converter to attain the wide output dynamic range and high linearity. The proposed design is implemented using$0.18~\mu \text{m}$HV process. The measurement results show that the temperature sensing errors are from −0.19°C to +0.34°C with the temperature sensing range from −40 °C to 70 °C. The output dynamic range is 2.825.