This project centers on the development of a custom system-on-chip (SoC)for electrocardiogram (ECG) acquisition and analysis. ECG data is important for medical diagnosis of general health and of many specific conditions, including a variety of cardiac arrhythmias. Existing methods of capturing ECG outside of the clinical setting, such as Holter monitors or event monitors, either have limited lifetimes or non continuous acquisition. This project seeks to develop custom hardware to dramatically extend the lifetime of ECG acquisition circuits by fabricating a custom SoC.
To determine the features required on the chip, we first developed a discrete prototype of the system. The prototype used commercial off the shelf (COTS) hardware in a custom system that acquired ECG data and wirelessly communicated it to a handheld. The first prototype of the custom IC integrated the analog front end and the digital processing onto a system on chip. The 130nm CMOS SoC uses low voltage design for energy efficient operation. Our chip gallery gives more more details on the chip. The analog front end comprises an instrumentation amplifier and an analog to digital converter. These analog components are biased in sub-threshold to reduce current consumption. The digital processor is a custom microcontroller based on the PIC architecture. The microcontroller operates in the sub-threshold region. Its minimum energy voltage occurs at 280mV, where it was measured to consume just 1.5pJ per instruction. The SoC can acquire ECG data and execute a heart rate extraction algorithm while consuming only 2.6uW.
Faculty: Ben Calhoun, Travis Blalock Students: Steve Jocke, Jonathan Bolus, Stuart Wooters