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A Single-Chip CMOS Pulse Oximeter with On-Chip Lock-In Detection.

He D, Morgan SP, Trachanis D, van Hese J, Drogoudis D, Fummi F, Stefanni F, Guarnieri V, Hayes-Gill BR - Sensors (Basel) (2015)

Bottom Line: The experimentally measured AC and DC characteristics of individual circuits including the DC output voltage of the transimpedance amplifier, transimpedance gain of the transimpedance amplifier, and the central frequency and bandwidth of the analogue band-pass filters, show a good match (within 1%) with the circuit simulations.With modulated light source and integrated lock-in detection the sensor effectively suppresses the interference from ambient light and 1/f noise.The single-chip sensor enables a compact and robust design solution that offers a route towards wearable devices for health monitoring.

View Article: PubMed Central - PubMed

Affiliation: Electrical System and Optics Research Division, Faculty of Engineering, University of Nottingham, University Park, Nottingham NG7 2RD, UK. diwei.he@nottingham.ac.uk.

ABSTRACT
Pulse oximetry is a noninvasive and continuous method for monitoring the blood oxygen saturation level. This paper presents the design and testing of a single-chip pulse oximeter fabricated in a 0.35 µm CMOS process. The chip includes photodiode, transimpedance amplifier, analogue band-pass filters, analogue-to-digital converters, digital signal processor and LED timing control. The experimentally measured AC and DC characteristics of individual circuits including the DC output voltage of the transimpedance amplifier, transimpedance gain of the transimpedance amplifier, and the central frequency and bandwidth of the analogue band-pass filters, show a good match (within 1%) with the circuit simulations. With modulated light source and integrated lock-in detection the sensor effectively suppresses the interference from ambient light and 1/f noise. In a breath hold and release experiment the single chip sensor demonstrates consistent and comparable performance to commercial pulse oximetry devices with a mean of 1.2% difference. The single-chip sensor enables a compact and robust design solution that offers a route towards wearable devices for health monitoring.

No MeSH data available.


Related in: MedlinePlus

Comparison of the SpO2 values for the CMOS sensor and two commercial devices (Masimo Radical 7 and Nexus-10) in transmission mode for a breath hold and release experiment.
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sensors-15-17076-f007: Comparison of the SpO2 values for the CMOS sensor and two commercial devices (Masimo Radical 7 and Nexus-10) in transmission mode for a breath hold and release experiment.

Mentions: Figure 7 shows a comparison of the CMOS sensor chip (HeartLight) with two CE marked & FDA approved commercial pulse oximeters (Masimo Radical 7 and Nexus-10) in transmission geometry during a “breath hold and release” experiment. Using Equation (3) the SpO2 values of the CMOS sensor were determined from the measured R ratio values. Figure 7 shows that the output of the CMOS sensor is generally in agreement with the two commercial SpO2 devices. It can be seen that the oxygen saturation decreases from 98% to 88% during the breath holding period and then increases sharply back to 98% and the CMOS sensor chip faithfully follows this trend.


A Single-Chip CMOS Pulse Oximeter with On-Chip Lock-In Detection.

He D, Morgan SP, Trachanis D, van Hese J, Drogoudis D, Fummi F, Stefanni F, Guarnieri V, Hayes-Gill BR - Sensors (Basel) (2015)

Comparison of the SpO2 values for the CMOS sensor and two commercial devices (Masimo Radical 7 and Nexus-10) in transmission mode for a breath hold and release experiment.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4541923&req=5

sensors-15-17076-f007: Comparison of the SpO2 values for the CMOS sensor and two commercial devices (Masimo Radical 7 and Nexus-10) in transmission mode for a breath hold and release experiment.
Mentions: Figure 7 shows a comparison of the CMOS sensor chip (HeartLight) with two CE marked & FDA approved commercial pulse oximeters (Masimo Radical 7 and Nexus-10) in transmission geometry during a “breath hold and release” experiment. Using Equation (3) the SpO2 values of the CMOS sensor were determined from the measured R ratio values. Figure 7 shows that the output of the CMOS sensor is generally in agreement with the two commercial SpO2 devices. It can be seen that the oxygen saturation decreases from 98% to 88% during the breath holding period and then increases sharply back to 98% and the CMOS sensor chip faithfully follows this trend.

Bottom Line: The experimentally measured AC and DC characteristics of individual circuits including the DC output voltage of the transimpedance amplifier, transimpedance gain of the transimpedance amplifier, and the central frequency and bandwidth of the analogue band-pass filters, show a good match (within 1%) with the circuit simulations.With modulated light source and integrated lock-in detection the sensor effectively suppresses the interference from ambient light and 1/f noise.The single-chip sensor enables a compact and robust design solution that offers a route towards wearable devices for health monitoring.

View Article: PubMed Central - PubMed

Affiliation: Electrical System and Optics Research Division, Faculty of Engineering, University of Nottingham, University Park, Nottingham NG7 2RD, UK. diwei.he@nottingham.ac.uk.

ABSTRACT
Pulse oximetry is a noninvasive and continuous method for monitoring the blood oxygen saturation level. This paper presents the design and testing of a single-chip pulse oximeter fabricated in a 0.35 µm CMOS process. The chip includes photodiode, transimpedance amplifier, analogue band-pass filters, analogue-to-digital converters, digital signal processor and LED timing control. The experimentally measured AC and DC characteristics of individual circuits including the DC output voltage of the transimpedance amplifier, transimpedance gain of the transimpedance amplifier, and the central frequency and bandwidth of the analogue band-pass filters, show a good match (within 1%) with the circuit simulations. With modulated light source and integrated lock-in detection the sensor effectively suppresses the interference from ambient light and 1/f noise. In a breath hold and release experiment the single chip sensor demonstrates consistent and comparable performance to commercial pulse oximetry devices with a mean of 1.2% difference. The single-chip sensor enables a compact and robust design solution that offers a route towards wearable devices for health monitoring.

No MeSH data available.


Related in: MedlinePlus