Compact Temperature Sensor with Voltage-Ratio Current-Independent Output for Reference Independent Data Conversion

A compact CMOS temperature sensor suitable for on-chip power/thermal management designed to monitor hotspot formation at multiple locations on a die is introduced. Temperature information is embedded in the ratio of two voltage outputs of the sensor to facilitate temperature to digital conversion without the need for a separate reference for the data converter. The sensor is highly insensitive to temperature or stress-dependent bias current variations. Measured results in a sensor with devices from a 0.5μm CMOS process show an error of ±0.5°C over the temperature range of -10°C to 100°C when biased with a constant current. Even with ±5% variation in bias current an error of less than ±1°C over the -10°C to 100°C temperature range is achieved.