CMOS Temperature Sensor with Programmable Temperature Range for Biomedical Applications

A CMOS temperature sensor circuit with programmable temperature range is proposed for
biomedical applications. The proposed circuit consists of temperature sensor core circuit
and programmable temperature range digital interface circuit. Both circuits are able to be
operated at 1.0 V. The proposed temperature sensor circuit is operated in weak inversion
region of MOSFETs. The proposed digital interface circuit converts current into time using
Current-to-Time Converter (ITC) and converts time to digital data using counter. Temperature
range can be programmed by adjusting pulse width of the trigger and clock frequency
of counter. The proposed circuit was simulated using HSPICE with 1P, 5M, 3-wells, 0.18-
m CMOS process (BSIM3v3.2, LEVEL53). From the simulation of proposed circuit,
temperature range is programmed to be 0 °C to 100 °C, it is obtained that resolution of the
proposed circuit is 0.392 °C with -0.89/+0.29 °C inaccuracy and the total power consumption
is 22.3 W in 25 °C.