Highly Accurate, Fully Digital Temperature Sensor With Curvature Correction

Abstract

In this paper, a highly accurate, fully digital temperature sensor with a curvature correction scheme is proposed. Conventional analog temperature sensors are complex and require a large area. Digital temperature sensors are simple with small area, but they have large inaccuracies due to process variations and curvature errors. In particular, curvature errors become more severe as the technology scales down. Thus, a highly accurate curvature correction method is proposed that can be used even in the latest technology nodes. The proposed curvature correction method achieves lower temperature errors with a smaller area than the conventional curvature correction method by using a simple correction. A temperature error that occurs up to 17 °C before the curvature correction is reduced to a range of −0.6 °C to +0.8 °C after the curvature correction. In addition, the measurement results indicate that the resolution is 0.09 °C /bit in the temperature range from 0 °C to 100 °C. The implementation in 14 nm technology node Xilinx ZCU102 field-programmable gate arrays proves that the proposed temperature sensor is very cost effective, while using only 85 slices. Compared with previous digital temperature sensors, the proposed temperature sensor achieves the smallest error and uses the smallest number of hardware resources while being implemented in a state-of-the-art technology node.