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Low-Power Photoplethysmogram Acquisition Integrated Circuit with Robust Light Interference Compensation.
Jongpal Kim1, Jihoon Kim2, Hyoungho Ko3
1Samsung Electronics Inc., Suwon 16678, Korea. jongpalk@samsung.com.
Sensors (Basel, Switzerland)
|January 6, 2016
Summary
This study presents a robust photoplethysmogram (PPG) readout chip designed to minimize light interference. The novel chip effectively compensates for DC offset and ambient light variations, ensuring accurate PPG signal acquisition.
Area of Science:
- Biomedical Engineering
- Integrated Circuit Design
- Optical Sensing
Background:
- Photoplethysmogram (PPG) signals are susceptible to light interference, including DC offset and ambient light variations.
- Existing PPG readout circuits often struggle with robustness against these environmental and optical path changes.
- Accurate PPG signal acquisition is crucial for various health monitoring applications.
Purpose of the Study:
- To develop a robust photoplethysmogram (PPG) readout chip using a 0.13-μm CMOS process.
- To address challenges posed by large DC offset, optical path variations, and ambient light interference.
- To achieve low power consumption and low noise in the PPG readout channel.
Main Methods:
- Fabrication of a PPG readout chip using a 0.13-μm CMOS process.
- Implementation of a saturation detection and current feedback circuit for DC offset compensation (up to 30 μA).
- Adoption of an automatic emitted light compensation method for optical path variation robustness.
- Proposal of an alternating sampling and charge redistribution technique to prevent ambient light interference, requiring minimal additional components (3 differential switches, 1 capacitor) and no extra power.
Main Results:
- The fabricated PPG readout chip demonstrates robustness against significant DC offset and ambient light variations.
- The proposed alternating sampling technique effectively mitigates ambient light interference without additional power consumption.
- The PPG readout channel achieves a low power consumption of 26.4 μW.
- The input-referred current noise is measured at 260 pArms.
Conclusions:
- The developed CMOS PPG readout chip offers a robust solution for accurate PPG signal acquisition in the presence of light interference.
- The integrated compensation techniques provide enhanced performance against DC offset and ambient light variations.
- The low power consumption and low noise characteristics make the chip suitable for portable and wearable health monitoring devices.
