A 187-pW 51-ppm/°C Self-Adjusting Voltage Reference Circuit

This paper proposed a novel pico-watt voltage reference (VR) circuit for the Internet of Things (IoT) applications. The core circuit consists of purely NMOS transistors operating in the sub-threshold region. This circuit contains a high-precision, high-power VR circuit (VRH) and a low-power, low-accuracy adjustable VR circuit (VRL). After initialization, the output voltage of VRL is adjusted based on the output voltage of VRH automatically. VRH is turned off to save energy when adjustment is completed. After waiting a period of time, VRH is turned on again to calibrate the output voltage of VRL. Thus, with self-adjusting topology, our proposed circuit achieves high accuracy and low power consumption. The output voltage is 168.5mV, while the power consumption is only 187pW and the temperature coefficient (TC) is 51 ppm/°C from -40°C to 85°C.