Heart rate data collection

• US 10,512,407 B2
• Filed: 03/06/2015
• Issued: 12/24/2019
• Est. Priority Date: 06/24/2013
• Status: Active Grant

• Current Assignee: Fitbit, Inc. (Alphabet Inc.)
• Original Assignee: Fitbit, Inc. (Alphabet Inc.)
• Inventors: Richards, Peter W., Elliot, Thomas Samuel, Yuen, Shelten Gee Jao
• Primary Examiner(s): Moher, Amanda Lauritzen
• Application Number:
  US14/640,281
• Publication Number:
  US 20150173631A1
• Time in Patent Office: 1,754 Days
• CPC Class Codes: A61B 2503/10 Athletes
• CPC Class Codes: A61B 2505/09 Rehabilitation or training
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/02055 Simultaneously evaluating both cardiovascular condition and temperature
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/02405 Determining heart rate variability
• CPC Class Codes: A61B 5/02427 Details of sensor
• CPC Class Codes: A61B 5/1112 Global tracking of patients, e.g. by using GPS
• CPC Class Codes: A61B 5/1118 Determining activity level
• CPC Class Codes: A61B 5/1123 Discriminating type of movement, e.g. walking or running A61B5/1116, A61B5/112 take precedence
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/165 Evaluating the state of mind, e.g. depression, anxiety
• CPC Class Codes: A61B 5/4806 Sleep evaluation A61B5/4821 takes precedence; devices for inducing sleep A61M21/02
• CPC Class Codes: A61B 5/4812 Detecting sleep stages or cycles
• CPC Class Codes: A61B 5/4815 Sleep quality
• CPC Class Codes: A61B 5/681 Wristwatch-type devices
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/7207 of noise induced by motion artifacts
• CPC Class Codes: A61B 5/721 using a separate sensor to detect motion or using motion information derived from signals other than the physiological signal to be measured
• CPC Class Codes: A61B 5/7221 Determining signal validity, reliability or quality A61B5/7207 and A61B5/7217 take precedence
• CPC Class Codes: A61B 5/7235 : Details of waveform analysis A61B5/349 takes precedence
• CPC Class Codes: A61B 5/7264 : Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems neural networks per se G06N3/00; expert systems per se G06N5/00
• CPC Class Codes: A61B 5/7282 : Event detection, e.g. detecting unique waveforms indicative of a medical condition A61B5/4094, A61B5/4818, A61B5/349, A61B5/0823 take precedence

Abstract

One innovative aspect is directed to heart rate data collection. In some implementations, a circuit includes a light detector for generating a first electrical signal based on received light. The circuit includes a switching circuit, having a first and a second configuration, configured to receive a first voltage signal based on the first electrical signal and to switch among the first and the second configurations. The circuit includes first and second sampling circuits for sampling a value of the first voltage signal when the switching circuit is in the first configuration and second configurations, respectively. The circuit includes an ambient light cancellation circuit for generating a current signal to counter a first component of the first electrical signal when the first switching circuit is in the first configuration.

Claims

1. A device, comprising:

a controller, the controller configured to, responsive to receiving a request to initiate a capture process, cause a first gain to be set in a first amplifier at a first time and to cause a light emitter control signal to be generated, wherein the light emitter control signal is configured to cause a light emitter to emit light towards a target surface;

a first sampling circuit comprising a second amplifier and configured to capture, while the first gain remains set and using the first amplifier and the second amplifier, at least one sample of a detected incident light signal received by the first sampling circuit while the light emitter control signal is generated to produce an analog representation of the detected incident light signal; and

an analog-to-digital converter configured to convert the analog representation of the detected incident light signal into a digital representation for further processing by the controller, wherein the controller is further configured to cause the light emitter control signal to stop and the first sampling circuit to be disabled substantially simultaneously with causing the analog-to-digital converter to convert the analog representation of the detected incident light signal into the digital representation.

2. The device of claim 1, wherein the digital representation is representative of a heartbeat of a user of the device.

3. The device of claim 1, wherein the controller is further configured to set a gain associated with an ambient light detection process.

4. The device of claim 3, further comprising:

a light detector configured to detect ambient light and generate an ambient light signal responsive to such ambient light detection; and

at least a second sampling circuit configured to sample the ambient light signal and produce, at least partially based on the gain of the ambient light detection process, an analog representation of the ambient light signal for use in canceling an ambient component of the analog representation of the detected light signal.

5. The device of claim 1, wherein the controller is further configured to:

disable, during the capture process, a zeroing of a light detector prior to causing the light emitter control signal to be generated.

6. The device of claim 5, wherein the controller is further configured to:

enable the zeroing of the light detector after causing the generation of the light emitter control signal to stop.

7. The device of claim 1, wherein the controller is further configured to:

cause a light emitter reset signal to be generated, reset the at least the first sampling circuit, and reset the at least the first amplifier after the capture process is completed in preparation for a further request to perform the capture process.

8. The device of claim 4, wherein the second sampling circuit is configured to:

adjust or select an impedance based on the gain of the ambient light detection process; and

generate a gain adjustment signal to adjust a gain of the analog representation of the ambient light signal based on the gain of the ambient light detection process.

9. The device of claim 1, wherein the controller is further configured to set the first gain of the first amplifier based at least in part on historical data received by the controller.

10. The device of claim 4, wherein the second sampling circuit is configured to set the gain of the ambient light detection process based at least in part on historical ambient light data received by the controller.

11. A device, comprising:

an input device configured to receive an input and generate, responsive thereto, a signal indicating a request to perform a capture process; and

a controller, communicatively connected with the input device and configured to;

receive the signal from the input device;

set, responsive to receiving the signal, a first gain of at least a first amplifier at a first time;

cause, after setting the first gain, a light emitter of the device to emit a light signal;

cause a first sampling circuit, the first sampling circuit including a second amplifier, to capture, while the first gain remains set, at least one sample of a detected incident light signal routed through the first amplifier and the second amplifier to produce an analog representation of the detected incident light signal;

cause an analog-to-digital converter to convert the analog representation of the detected incident light signal into a digital representation for further processing by the controller; and

cause the light emitter and the first sampling circuit to be disabled substantially simultaneously with causing the conversion of the analog representation of the detected incident light signal into the digital representation by the analog-to-digital converter.

12. The device of claim 11, wherein the detected incident light signal is a light signal obtained from a target.

13. The device of claim 11, wherein the controller is further configured to:

set a gain of an ambient light detection process;

cause a light detector to detect an ambient light signal; and

sample the ambient light signal at least partially based on the gain of the ambient light detection process to produce an analog representation of the ambient light signal.

14. The device of claim 13, further comprising an ambient light cancellation circuit configured to counter a component of the analog representation of the detected incident light signal attributable to ambient light using the analog representation of the ambient light signal.

15. The device of claim 14, wherein the controller is configured to operate the analog-to-digital converter after a first delay period, the first delay period selected to allow the component of the detected incident light signal attributable to ambient light to be countered by the analog representation of the ambient light signal.

16. The device of claim 14, wherein the controller is configured to operate the analog-to-digital converter after a first delay period, the first delay period selected to allow the analog-to-digital converter to settle to a known state.

17. The device of claim 11, wherein the controller is further configured to disable, as part of the capture process, a zeroing of a light detector prior to causing the light emitter to emit the light signal.

18. The device of claim 17, wherein the controller is further configured to enable the zeroing of the light detector after the disabling of the light emitter.

19. The device of claim 11, wherein the controller is further configured to reset the light emitter and the first sampling circuit in preparation for a further request to perform a sampling process.

20. The device of claim 13, further comprising a second sampling circuit configured to:

sample the ambient light signal,

adjust or select an impedance based on the gain of the ambient light detection process; and

generate a gain adjustment signal based on the gain of the ambient light detection process to adjust a gain of the analog representation of the ambient light signal.

21. The device of claim 11, wherein the controller is further configured to set the first gain of the first amplifier based at least in part on historical data received by the controller.

22. The device of claim 13, wherein the second sampling circuit is configured to set the gain of the ambient light detection process based at least in part on historical ambient light data received by the controller.

23. The device of claim 11, wherein the digital representation is representative of a detected heartbeat of a user.