MULTI-STREAM SENSOR FRONT ENDS FOR NONINVASIVE MEASUREMENT OF BLOOD CONSTITUENTS

• US 20140155712A1
• Filed: 01/13/2014
• Published: 06/05/2014
• Est. Priority Date: 08/04/2008
• Status: Active Grant

• Current Assignee: Masimo Corporation
• Original Assignee: Cercacor Laboratories
• Inventors: Lamego, Marcelo M., Merritt, Sean, Dalvi, Cristiano, Vo, Hung, Bruinsma, Johannes, Lesmana, Ferdyan, Kiani, Massi Joe E., Poeze, Jeroen
• Granted Patent: US 8,909,310 B2
• Time in Patent Office: Days
• US Class Current: 600/310
• CPC Class Codes: A61B 2562/0233 Special features of optical sensors or probes classified in A61B5/00
• CPC Class Codes: A61B 2562/04 Arrangements of multiple sensors of the same type
• CPC Class Codes: A61B 2562/046 in a matrix array
• CPC Class Codes: A61B 2562/146 for optical coupling
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/02427 Details of sensor
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/4875 Hydration status, fluid retention of the body
• CPC Class Codes: A61B 5/6816 Ear lobe
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/6829 Foot or ankle
• CPC Class Codes: A61B 5/6838 Clamps or clips
• CPC Class Codes: A61B 5/6843 Monitoring or controlling sensor contact pressure
• CPC Class Codes: A61B 5/70 Means for positioning the patient in relation to the detecting, measuring or recording means
• CPC Class Codes: A61B 5/7275 Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor

Abstract

The present disclosure relates to an interface for a noninvasive glucose sensor that comprises a front-end adapted to receive an input signals from optical detectors and provide corresponding digital signals. In one embodiment, the front-end comprises switched capacitor circuits that are capable of handling multiple streams signals from the optical detectors. In another embodiment, the front-end comprises transimpedance amplifiers that are capable of handling multiple streams of input signals. In this embodiment, the transimpedance amplifier may be configured based on its own characteristics, such as its impedance, the impedance of the photodiodes to which it is coupled, and the number of photodiodes to which it is coupled.

Claims

1. A front-end interface for a noninvasive, physiological sensor, said front-end interface comprising:

a set of inputs configured to receive signals from a plurality of detectors in the sensor;

a set of switched capacitor circuits configured to convert the signals from the plurality of detectors into a digital output signal having a stream for each of the plurality of detectors; and

an output configured to provide the digital output signal.

2. The front-end interface of claim 1, wherein the front-end interface is integrated with the sensor.

3. The front-end interface of claim 1, wherein the set of switched capacitor circuits are configured to combine the streams of a set of the detectors into a single stream.

4. A conversion processor for a physiological, noninvasive sensor, said board comprising:

a multi-stream input configured to receive signals from a plurality of detectors in the sensor, wherein the signals are responsive to optical radiation from a tissue site;

a modulator that converts the multi-stream input into a digital bit-stream; and

a signal processor that produces an output signal from the digital bit-stream.

5. The conversion processor of claim 4, wherein at least one of the detectors in the sensor comprise a set of photodiodes coupled together into a group.

6. The conversion processor of claim 5, wherein the at least one detector in the sensor comprise a set of two photodiodes coupled together.

7. The conversion processor of claim 5, wherein the at least one detector in the sensor comprise a set of three photodiodes coupled together.

8. The conversion processor of claim 5, wherein the at least one detector in the sensor comprise a set of four photodiodes coupled together.

9. The conversion processor of claim 5, wherein the at least one detector in the sensor comprise a set of nine photodiodes coupled together.

10. The conversion processor of claim 5, wherein the at least one detector in the sensor comprise a set photodiodes coupled together to provide a detection area of approximately 1 mm².

11. A front-end interface for a noninvasive, physiological sensor, said front-end interface comprising:

a set of inputs configured to receive signals from a plurality of detectors in the sensor;

a set of respective transimpedance amplifiers for each detector configured to convert the signals from the plurality of detectors into an output signal having a stream for each of the plurality of detectors; and

an output configured to provide the output signal.

12. The front-end interface of claim 11, further comprising an averager, coupled to the transimpedance amplifiers and the output, configured to average the digital output signals from the transimpedance signal into a single output signal.

13. The front-end interface of claim 11, wherein at least one of the detectors in the sensor comprise a set of photodiodes coupled together into a group.

14. The front-end interface of claim 12, wherein the at least one detector in the sensor comprise a set of two photodiodes coupled together.

15. The front-end interface of claim 12, wherein the at least one detector in the sensor comprise a set of three photodiodes coupled together.

16. The front-end interface of claim 12, wherein the at least one detector in the sensor comprise a set of four photodiodes coupled together.

17. The front-end interface of claim 12, wherein the at least one detector in the sensor comprise a set of nine photodiodes coupled together.

18. The front-end interface of claim 12, wherein the at least one detector in the sensor comprise a set photodiodes coupled together to provide a detection area of approximately 1 mm².