CMOS digital integrated temperature sensor

Substrate PNP transistors were as the temperature sensing devices. The PTAT current generator and CTAT current generator were designed based on the theory of band-gap reference (BGR). The BGR circuit was adapted to self-bias and common source and common gate current mirror structure in order to obtain low power consumption, high linear and high PSRR (power supply rejection ratio). The temperature modulate circuit was designed with the current-input mode Sigma-Delta converter and duty-cycle-modulate type output, which was designed incorporated with the forestage BGR circuit, and the voltage reference generator was the expansion of the BGR. The CSMC 0.6mum process model library was chosen for design. And the Cadence Spectre simulator was used for the circuits´ simulation and test. The results displayed that the minimum accuracy of the temperature sensor we designed was 0.5degC at the range of -40degC~+140degC, and the minimum power consumption was just 500muW