A low-power PPG readout IC achieved a high dynamic range of 108.2 dB while dissipating 15.7 μW in the light-to-digital converter and 264 μW in the LED driver.
A novel low-power readout IC demonstrates high-fidelity PPG signal recording with high dynamic range and low power consumption.
This paper reports on a low-power readout IC (ROIC) for high-fidelity recording of the photoplethysmogram (PPG) signal. The system comprises a highly reconfigurable, continuous-time, second-order, incremental delta-sigma modulator (I-ΔΣM) as a light-to-digital converter (LDC), a 2-channel 10b light-emitting diode (LED) driver, and an integrated digital signal processing (DSP) unit. The LDC operation in intermittent conversion phases coupled with digital assistance by the DSP unit allow signal-aware, on-the-fly cancellation of the dc and ambient light-induced components of the photodiode current for more efficient use of the full-scale input range for recording of the small-amplitude, ac, PPG signal. Fabricated in TSMC 0.18 μm 1P/6M CMOS, the PPG ROIC exhibits a high dynamic range of 108.2 dB and dissipates on average 15.7 μW from 1.5 V in the LDC and 264 μW from 2.5 V in one LED (and its driver), while operating at a pulse repetition frequency of 250 Hz and 3.2% duty cycling. The overall functionality of the ROIC is also demonstrated by high-fidelity recording of the PPG signal from a human subject fingertip in the presence of both natural light and indoor light sources of 60 Hz.
Marefat et al. (Fri,) conducted a other in Photoplethysmogram (PPG) recording. PPG-Readout IC with Reconfigurable, 2nd-Order, Incremental ΔΣM Front-End was evaluated on Dynamic range and power dissipation. A low-power PPG readout IC achieved a high dynamic range of 108.2 dB while dissipating 15.7 μW in the light-to-digital converter and 264 μW in the LED driver.
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