Time-Domain Smart Temperature Sensor Using Current Starved Inverters and Switched Ring Oscillator-Based Time-to-Digital Converter

摘要

This article reports a time-domain smart temperature sensor using current starved inverters (CSIs) and switched ring oscillator-based time-to-digital converter (SRO-TDC) in a standard 180nmCMOS process. A novel temperature-to-time converter (TTC) is proposed using complementary delay lines, which are designed by utilising CSIs. The proportional to absolute temperature delay line offers a temperature coefficient (TC) of 615 ppm/circle Cwhereas the complementary to absolute temperature delay line possesses a TC of 300 ppm/circle Cover 0-100 circle Ctemperature range. A novel multipath delay cell-based coupled oscillator is proposed for SRO-TDC. The proposed SRO-TDC operates as readout circuit for the sensor, which achieves 30 ns range at 12 ps resolution. The uncertainty of the sensor is limited to +/- 0.63 circle Cafter the 2-point calibration at 20 circle C and 80 circle C which is because of complementary delay lines in TTC and noise shaping behaviour of the SRO-TDC. The sensor achieves 0.4 mu s conversion time at 0. 04 circle Cresolution.