A Sensor System to Detect Positive and Negative Current-Temperature Dependences

We present a sensor system that determines if the circuit current-temperature (I - T) dependence is positive or negative. While prior temperature sensors can prevent overheating and temperature-induced timing failures in systems with negative I - T dependences, the proposed sensor system can prevent these issues in systems with negative or positive I - T dependences. This capability will become increasingly critical as technology scaling results in positive I - T dependences occurring at near-nominal operating voltages. The fabricated sensor system occupies <; 0.05 mm², consuming 310 nJ per sample with 20- μs latency in 0.35-μm technology. A process variation compensation unit is presented for the calibration of the temperature sensor, which has a temperature nonlinearity of as low as 0.2%. Sensor functionality is verified over a temperature range of 5°C-80°C and a voltage range of 0.6-3.3 V. The system is shown to achieve this improved functionality while maintaining comparable area, energy, and accuracy with alternative temperature sensor designs.