CMOS temperature sensor with constant power consumption multi-level comparator for implantable bio-medical devices

A new fully integrated CMOS temperature sensing system applicable for implantable bio-medical devices with low power and mixed-mode signal output is presented. The proposed system includes a novel multi-level comparator which has constant maximum power consumption even with the addition of more stages. The circuit was verified using TSMC 0.35 ¿m mixed-signal 2P4M 3.3/5 V models. Simulation results show the proposed circuit adapted well to the application for a narrow temperature range in implantable systems and only consumed 37.3 W at 2.5 V power supply.