A power-efficient multi-channel PPG ASIC with 112dB receiver DR for pulse oximetry and NIRS

We report a photo-plethysmography ASIC realised in a 130nm CMOS technology, which supports multi-channel probe configurations with up to 32 LEDs and 4 photodiodes. The receiver can cover a wide range of (full-scale) input signal strengths between 13nA and 63μA. In a typical pulse oximetry application (0.1–20Hz), overall loop dynamic range is 96dB, with noise contributions by the driver, LED, photodiode and receiver all taken into account. Total power consumption is 5.9mW, including two LEDs pulsed at 600Hz and 50mA. Compared to the state-of-the-art a saving of 68% has been achieved for equal signal quality.