Limits...
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.


Comparison of the SpO2 outputs of the CMOS sensor and a Masimo Radical-7 in reflectance mode for a breath hold and release experiment.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4541923&req=5

sensors-15-17076-f008: Comparison of the SpO2 outputs of the CMOS sensor and a Masimo Radical-7 in reflectance mode for a breath hold and release experiment.

Mentions: A comparison is also made between the CMOS sensor chip and the Masimo Radical 7 in reflectance mode in Figure 8 using a breath hold and release experiment. It should be noted that the Nexus-10 can only be used in transmission mode and hence the data is not available. In addition as the finger simulator is not valid in reflection geometry then it was not possible to generate an accurate calibration curve. However, for direct comparison illustrating the experimental trend, rather than an accurate quantification, Equation (3) was still applied. The results of Figure 8 illustrate that the CMOS sensor output generally reads 6% lower than the Masimo Radical-7 output but nevertheless they show a good agreement in terms of the timing and trend of the % of increase/decrease during the breath hold and release experiment.


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 outputs of the CMOS sensor and a Masimo Radical-7 in reflectance 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-f008: Comparison of the SpO2 outputs of the CMOS sensor and a Masimo Radical-7 in reflectance mode for a breath hold and release experiment.
Mentions: A comparison is also made between the CMOS sensor chip and the Masimo Radical 7 in reflectance mode in Figure 8 using a breath hold and release experiment. It should be noted that the Nexus-10 can only be used in transmission mode and hence the data is not available. In addition as the finger simulator is not valid in reflection geometry then it was not possible to generate an accurate calibration curve. However, for direct comparison illustrating the experimental trend, rather than an accurate quantification, Equation (3) was still applied. The results of Figure 8 illustrate that the CMOS sensor output generally reads 6% lower than the Masimo Radical-7 output but nevertheless they show a good agreement in terms of the timing and trend of the % of increase/decrease during the breath hold and release experiment.

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.