A 15-μA metabolic equivalents monitoring system using adaptive acceleration sampling and normally off computing

This paper describes a low-power metabolic equivalents (METs) estimation method for monitoring physical activity. Long-term continuous METs monitoring can contribute to detection of non-communicable diseases. The proposed system consists of dedicated METs estimation hardware and a non-volatile CPU. A test is fabricated in a 130-nm CMOS with a ferroelectric capacitor process. Evaluation results show that the proposed system, which consists of the test chip and an accelerometer, requires about 15-μA on average.