Building an ultra low-power analog-to-digital converter for medical applications

Electronic sensors and devices are increasingly small and precise enough to be incorporated in medical implants. These devices, such as pacemakers and cardiovascular monitors, measure an analog signal and must convert it to digital for analysis. This analog-to-digital conversion requires a lot of power and minimizing it is critical for medical applications.

Chen et al. developed an ultra low-power analog-to-digital converter for use in medical implant devices. Their design could lead to longer lasting implants and fewer invasive surgeries.

“A lower power consumption means a longer working time for battery-powered implant devices,” said author Yan Xue. “A pacemaker, for example, needs to work more than 10 years in the human body. If the power consumption can be reduced by half, the number of surgeries to replace batteries are also reduced by half.”

To reach this lower power consumption, the team relied on three novel techniques: a tri-state capacitor unit, a novel switch scheme, and a low static power comparator. Combined, these techniques resulted in a power draw of only 24 nanowatts, less than half as much as other designs, without sacrificing speed or performance.

“Our work achieved a good balance between conversion speed, performance, and power consumption,” said Xue. “This is a particularly huge improvement, especially for applications with high requirements for precision and power consumption.”

The authors plan to further optimize their design to account for the abrupt properties of biomedical signals.

“A biomedical signal may rest for a long time and suddenly change dramatically,” said Xue. “Our current research focuses on how to further reduce power consumption on this basis.”

Source: “A 24nW 10-bits 10kS/s ultra low-power SAR ADC for bio-medical devices,” by Yanbo Chen, Qiong Nie, Chaowei Zhong, Jiayi Song, Yinfeng Huang, Chengkai Lin, Qiming Zeng, Jie Cao, and Yan Xue, AIP Advances (2023). The article can be accessed at https://doi.org/10.1063/5.0138835 .

This paper is part of the 13th International Conference of the Chinese Society of Micro and Nanotechnology (CSMNT2022) Collection, learn more here .