Abstract-We introduce an electrocardiogram (EKG) preamplifier with a power consumption of 2.8 W, 8.1 V rms input-referred noise, and a common-mode rejection ratio of 90 dB. Compared to previously reported work, this amplifier represents a significant reduction in power with little compromise in signal quality. The improvement in performance may be attributed to many optimizations throughout the design including the use of subthreshold transistor operation to improve noise efficiency, gain-setting capacitors versus resistors, half-rail operation wherever possible, optimal power allocations among amplifier blocks, and the sizing of devices to improve matching and reduce noise. We envision that the micropower amplifier can be used as part of a wireless EKG monitoring system powered by rectified radio-frequency energy or other forms of energy harvesting like body vibration and body heat.Index Terms-Common-mode feedback (CMFB), electrocardiograph (ECG), electrocardiogram (EKG), low noise, low power.

New electronics for non-invasive medical monitoring promise low-cost, maintenance-free, and lightweight devices. These devices are critical in long-term medical measurements and in home-based tele-monitoring services, which are extremely important for the reduction of health care costs. Here, we present several methods for reducing power consumption while retaining precision. In particular, we focus on the monitoring of the heart-because of its importance-and we describe a micropower electrocardiograph, an ultra-low-power pulse oximeter, an ultra-low-power phonocardiograph, an integratedcircuit switched-capacitor model of the heart, and a low-power RF-antenna-powered CMOS rectifier for energy harvesting. We also introduce an ultra-low-power platform for medical monitoring that enables the integration of monitoring circuitry in a wireless, low-cost, and battery-free device, and describe a method for audio localization of the device in case of a medical alarm.

Ultralow-power electronics for cardiac monitoring make possible the development of new light-weight and low-cost devices that are ideal for long-term medical measurements and home-based tele-monitoring services. Nowadays, these devices are seen as a critical technology for reducing health-care costs. In this paper, we present several methods for reducing power consumption while retaining the precision necessary for cardiac monitoring. In particular, we describe a micropower electrocardiograph, an ultralow-power pulse oximeter, an ultralow-power phonocardiograph, an integrated-circuit switched-capacitor model of the heart, and an ultracompact and efficient lithium-ion battery charger. These components are, to our knowledge, currently the most power-efficient or minimal-size designs present in the literature in each respective category.