HEART RATE AND BLOOD OXYGEN MONITORING SYSTEM

• US 20150011851A1
• Filed: 01/10/2013
• Published: 01/08/2015
• Est. Priority Date: 01/10/2012
• Status: Active Grant

• Current Assignee: Maxim Integrated Products, Inc. (Analog Devices, Inc.)
• Original Assignee: Maxim Integrated Products, Inc. (Analog Devices, Inc.)
• Inventors: Olsen, Richard I., Christman, Daniel S., Mehta, Arpit
• Granted Patent: US 10,123,711 B2
• Time in Patent Office: Days
• US Class Current: 600/324
• CPC Class Codes: A61B 5/02433 for infrared radiation
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/6898 Portable consumer electronic devices, e.g. music players, telephones, tablet computers
• CPC Class Codes: A61B 5/7221 Determining signal validity, reliability or quality A61B5/7207 and A61B5/7217 take precedence
• CPC Class Codes: A61B 5/7257 using Fourier transforms

Abstract

An integrated circuit device includes an insulating body provided with a number of electrically conductive leads and having a surface provided with a red LED aperture, an IR LED aperture and a photodetector aperture. The insulating body also includes an optical isolator optically separating the photodetector aperture from the red LED aperture and the IR LED aperture. A red LED is aligned with the red LED aperture, an IR LED is aligned with the IR LED aperture, and a photodetector is aligned with the photodetector aperture.

Claims

1. An electronic device with heart rate monitor comprising:

a body including at least one infrared (IR) transmissive surface;

a digital processor located within the body;

a display screen supported by the body;

an IR light emitting diode (LED) aligned with the IR transmissive surface;

LED driving circuitry coupled to the IR LED;

an IR photodetector aligned with the IR transmissive surface;

a filtering and amplification stage having an input coupled to the IR photodetector;

an analog-to-digital converter (ADC) having an analog input coupled to an output of the filtering and amplification stage and a digital output; and

memory coupled to the digital processor including code segments executable by the digital processor for;

(a) detecting that a finger has been placed on the IR transmissive surface using the IR LED and IR photodetector;

(b) capturing raw data from the ADC;

(c) performing a Fast Fourier Transform (FFT) of the raw data to develop FFT data;

(d) processing the FFT data for at least one of window, averaging and noise rejection;

(e) calculating a heart rate; and

(f) at least one of displaying and storing the heart rate.

2. An electronic device with heart rate monitor as recited in claim 1 wherein the electronic device is a portable digital device and further comprises a wireless connection to a network.

3. An electronic device with heart rate monitor as recited in claim 2 wherein the network is at least one of a cellular telephone network and the Internet.

4. An electronic device with heart rate monitor as recited in claim 3 wherein the electronic device is one of a cellular telephone and a computer tablet.

5. An integrated circuit device comprising:

an insulating body provided with a number of electrically conductive leads and having a surface provided with a red LED aperture, an IR LED aperture and a photodetector aperture, the insulating body including an optical isolator separating the photodetector aperture from the red LED aperture and the IR LED aperture;

a red LED disposed within the insulating body and aligned with the red LED aperture;

an IR LED disposed within the insulating body and aligned with the IR LED aperture; and

a photodetector disposed within the insulating body and aligned with the photodetector aperture.

6. An integrated circuit device as recited in claim 5 further comprising circuitry disposed within the insulating body and coupled to the red LED, the IR LED, the photodetector and at least some of the electrically conductive leads.

7. An integrated circuit device as recited in claim 6 further comprising a filter disposed over the photodetector.

8. An integrated circuit device as recited in claim 7 wherein the filter is a compound filter including at least one red filter segment and at least one IR filter segment.

9. An integrated circuit device as recited in claim 8 wherein the compound filter is formed as a filter array of alternating red and IR filters.

10. An integrated circuit device as recited in claim 6 further comprising at least one lens disposed over at least one of the red LED, the IR LED and the photodetector.

11. A combination heart rate monitor and blood oxygen monitoring circuit comprising:

a red LED and an IR LED;

a red photodetector and an IR photodetector;

a filtering and amplification stage coupled to the red photodetector and the IR photodetector;

control circuitry receiving feedback from the filtering and amplification stage and controlling the currents to the red LED and the IR LED; and

an analog-to-digital converter (ADC) having an analog input coupled to an output of the filtering and amplification stage and having a digital output.

12. A combination heart rate monitor and blood oxygen monitoring circuit as recited in claim 11 further comprising registers for storing digital output of the ADC.

13. A combination heart rate and blood oxygen monitoring system as recited in claim 12 further comprising a digital signal processor (DSP) coupled to the registers for processing data stored therein.

14. A combination heart rate and blood oxygen monitoring system as recited in claim 13 wherein the filtering and amplification stage includes a series connection of a transimpedance amplifier (TIA) and a programmable gain amplifier (PGA).