Wide Range CMOS Voltage Detector with Low Current Consumption and Low Temperature Variation

Abstract

A wide range CMOS voltage detector with low current consumption consisting of CMOS inverters operating in both weak inversion and saturation region is proposed. A terminal of power supply for CMOS inverter can be expanded to a signal input terminal. A voltage-detection point and hysteresis characteristics of the proposed circuit can be designed by geometrical factor in MOSFET and an external bias voltage. The core circuit elements are fabricated in standard 0.18µm CMOS process and measured to confirm the operation. The detectable voltage is from 0.3V to 1.8V. The current consumption of voltage detection, standby current, is changed from 65pA for Vin =0.3V to 5.5µA for Vin =1.8V. The thermal characteristics from 250K to 400K are also considered. The measured temperature coefficient of the proposed voltage-detector core operating in weak inversion region is 4ppm/K and that in saturation region is 10ppm/K. The proposed voltage detector can be implemented with tiny chip area and is expected to an on-chip voltage detector of power supply for mobile application systems.