A 1-V 15uW High-Precision Temperature Switch

High precision temperature switches are required in a large number of today’s ICs for monitoring the die temperature. Upon detection of a too high die temperature measures to prevent over-heating of the chip can be taken; these measures include reducing the performance of large digital processors by setting lower supply voltages and/or lower clock frequencies. For this type of temperature detectors there are a number of functional and implementation-related demands. Firstly the temperature indication must be accurate in order to maintain maximum system performance. Secondly the power consumption (operational cost) of the detector must be negligibly small with respect to the total system’s power consumption. Thirdly the temperature switch must be monolithically integrated with digital processors: the temperature switch must be implemented in a standard CMOS process. Fourthly the required die area of the circuit (the production cost) must be minimal. This paper describes the design and measurements of a high-precision low-power low-voltage temperatureswitch circuit realized in a standard 0.18μm CMOS process. In contrast to a temperature sensor that measures the temperature [1,2] the presented circuit switches at a (or multiple) predefined temperatures.