An ECG-SoC with 535nW/channel lossless data compression for wearable sensors

This paper presents a low power ECG recording Sys-tem-on-Chip (SoC) with on-chip low complexity lossless ECG compression for data reduction in wireless/ambulatory ECG sensor devices. The proposed algorithm uses a linear slope predictor to estimate the ECG samples, and uses a novel low complexity dynamic coding-packaging scheme to frame the resulting estimation error into fixed-length 16-bit format. The proposed technique achieves an average compression ratio of 2.25× on MIT/BIH ECG database. Implemented in 0.35 μm process, the compressor uses 0.565 K gates/channel occupying 0.4 mm² for 4-channel, and consumes 535 nW/channel at 2.4V for ECG sampled at 512 Hz. Small size and ultra-low power consumption makes the proposed technique suitable for wearable ECG sensor application.