A 43.4μW Photoplethysmogram-Based Heart-Rate Sensor Using Heart-Beat-Locked Loop

📋 论文概要

本文提出一种基于心跳锁定环的超低功耗光电容积脉搏波（PPG）心率传感器，总功耗仅43.4μW。通过心跳锁定环技术大幅降低LED驱动器的占空比和功耗，解决了可穿戴设备中PPG传感器功耗过大的问题。

💡 主要创新点

• 提出心跳锁定环（Heart-Beat-Locked Loop）架构，使LED脉冲与心跳同步，显著降低平均驱动电流。
• 采用自适应占空比控制，根据心率变化动态调整LED开启时间，进一步节省功耗。
• 集成低噪声模拟前端和数字处理，在极低功耗下实现准确的心率检测。

🏷 关键词

📄 原文摘要

Photoplethysmogram (PPG) sensors have gained great popularity in recent years as they can easily obtain heart rate (HR) in wearable devices such as smart watches and smart rings. However, one of the biggest problems for PPG sensors is their large power consumption, as wearable devices are highly limited in its battery capacity. The power consumption of a PPG sensor is typically dominated by the LED driver, which requires several to a few tens of mA of current. Thus, many previous works are aimed at reducing the LED driver power [1-5]. The most widely used method is duty-cycling the LED by using a train of discrete pulses instead of always turning on the LED [1-4]. As a PPG signal has low bandwidth, the duty-cycle ratio of the LED can be as low as 1%. Another low-power method is compressive sampling, which exploits the sparse nature of PPG signals [5]. Although it can reduce the effective duty-cycle ratio down to 0.0125%, a critical

👥 作者与机构

Do-Hun Jang, SeongHwan Cho

KAIST, Daejeon, Korea