Circuits and methods for photoplethysmographic sensors
First Claim
1. A method for removing a component of a signal corresponding to ambient light in a photoplethysmographic sensor device, the method comprising:
- capturing, using a switch in a first position, a first detected light signal and holding the first detected light signal as voltage across a capacitor, the first detected light signal representing ambient light;
causing a light emitter to generate a source light signal driven at a first level;
capturing a second detected light signal, the second detected light signal representing the source light signal after interacting with a user'"'"'s tissue;
generating, using the switch in a second position, a first output signal based on the second detected light signal adjusted by the first detected light signal held in the capacitor;
changing the light emitter to generate a source light signal driven at a second level that is different than the first level;
capturing a third detected light signal, the third detected light signal representing the source light signal driven at the second level after interacting with the user'"'"'s tissue;
generating, using the switch in the second position, a second output signal based on the third detected light signal adjusted by the first detected light signal held in the capacitor; and
changing the light emitter again to generate the source light signal driven at the first level and capturing a fourth detected light signal representing the source light signal driven at the first level interacting with the user'"'"'s tissue;
generating a third output signal based on the fourth detected light signal adjusted by the first detected light signal held in the capacitor; and
generating a photoplethysmographic signal based on a weighted combination of the first, second, and third output signals,wherein initially detected ambient light is removed during the generating of the first, second, and third output signals, and dynamic changing ambient light is removed as a result of the weighted combination of the first, second, and third output signals.
1 Assignment
0 Petitions
Accused Products
Abstract
Some embodiments relate to a device, method, and/or computer-readable medium storing processor-executable process steps to remove a component of a signal corresponding to ambient light in a photoplethysmographic sensor device, including capturing a first detected light signal representing an ambient light at a first time, causing a light emitter to generate a source light signal driven at a first level, capturing a second detected light signal representing the source light signal after interacting with a user'"'"'s tissue plus the first detected light signal, generating a first output signal based on the second detected light signal adjusted by the first detected light signal, causing the light emitter to generate a source light signal driven at a second level, capturing a third detected light signal representing the source light signal driven at the second level after interacting with the user'"'"'s skin plus the first detected light signal, and generating a second output signal based on the third detected light signal adjusted by the first detected light signal.
-
Citations
25 Claims
-
1. A method for removing a component of a signal corresponding to ambient light in a photoplethysmographic sensor device, the method comprising:
-
capturing, using a switch in a first position, a first detected light signal and holding the first detected light signal as voltage across a capacitor, the first detected light signal representing ambient light; causing a light emitter to generate a source light signal driven at a first level; capturing a second detected light signal, the second detected light signal representing the source light signal after interacting with a user'"'"'s tissue; generating, using the switch in a second position, a first output signal based on the second detected light signal adjusted by the first detected light signal held in the capacitor; changing the light emitter to generate a source light signal driven at a second level that is different than the first level; capturing a third detected light signal, the third detected light signal representing the source light signal driven at the second level after interacting with the user'"'"'s tissue; generating, using the switch in the second position, a second output signal based on the third detected light signal adjusted by the first detected light signal held in the capacitor; and changing the light emitter again to generate the source light signal driven at the first level and capturing a fourth detected light signal representing the source light signal driven at the first level interacting with the user'"'"'s tissue; generating a third output signal based on the fourth detected light signal adjusted by the first detected light signal held in the capacitor; and generating a photoplethysmographic signal based on a weighted combination of the first, second, and third output signals, wherein initially detected ambient light is removed during the generating of the first, second, and third output signals, and dynamic changing ambient light is removed as a result of the weighted combination of the first, second, and third output signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
-
-
16. A method performed by a photoplethysmographic sensor device, the method comprising:
-
causing a light emitter to generate a source light signal driven at a first level; measuring a first detected light signal, the first detected light signal representing the source light signal driven at the first level interacting with a user'"'"'s skin, and subtracting ambient light from the first detected light signal to generate a first output signal; increasing the source light signal driven by the light emitter to a second level; measuring a second detected light signal, the second light signal representing the source light signal increased to the second level interacting with the user'"'"'s skin, and subtracting ambient light from the second detected light signal to generate a second output signal; decreasing the source light signal driven by the light emitter back to the first level; measuring a third detected light signal representing the source light signal driven at the first level interacting with the user'"'"'s skin, and subtracting ambient light from the third detected light signal to generate a third output signal; and generating a photoplethysmographic sample based on a weighted combination of the first, second, and third output signals, wherein dynamic changing ambient light is removed as a result of the weighted combination of the first, second, and third output signals.
-
-
17. A non-transitory computer-readable medium storing executable instructions for removing a component of a signal corresponding to ambient light in a photoplethysmographic sensor device, the instructions, when executed, cause one or more processors to:
-
capture, using a switch in a first position, a first detected light signal and holding the first detected light signal as voltage across a capacitor, the first detected light signal representing ambient light; cause a light emitter to generate a source light signal driven at a first level; capture a second detected light signal, the second detected light signal representing the source light signal interacting with a user'"'"'s tissue; generate, using the switch in a second position, a first output signal based on the second detected light signal adjusted by the first detected light signal held in the capacitor; change the light emitter to generate a source light signal driven at a second level that is different than the first level; capture a third detected light signal, the third detected light signal representing the source light signal driven at the second level interacting with the user'"'"'s tissue; generate, using the switch in the second position, a second output signal based on the third detected light signal adjusted by the first detected light signal held in the capacitor; change the light emitter again to generate the source light signal driven at the first level and capture a fourth detected light signal representing the source light signal driven at the first level interacting with the user'"'"'s tissue; generate a third output signal based on the fourth detected light signal adjusted by the first detected light signal held in the capacitor; and generate a photoplethysmographic signal based on a weighted combination of the first, second, and third output signals, wherein initially detected ambient light is removed during the generating of the first, second, and third output signals, and dynamic changing ambient light is removed as a result of the weighted combination of the first, second, and third output signals. - View Dependent Claims (18, 19, 20, 21, 22)
-
-
23. A photoplethysmographic sensor device, comprising:
-
one or more processors; non-transitory, computer readable medium storing instructions, which when executed, cause the one or more processors to; cause a light emitter to generate a source light signal driven at a first level; measure a first detected light signal, the first detected light signal representing the source light signal driven at the first level after interacting with a user'"'"'s skin, and subtract ambient light from the first detected light signal to generate a first output signal; increase the source light signal driven by the light emitter to a second level; measure a second detected light signal, the second light signal representing the source light signal increased to the second level after interacting with the user'"'"'s skin, and subtract ambient light from the second detected light signal to generate a second output signal; decrease the source light signal driven by the light emitter back to the first level; measure a third detected light signal representing the source light signal driven at the first level interacting with the user'"'"'s skin, and subtract ambient light from the third detected light signal to generate a third output signal; and generate a photoplethysmographic sample based on a weighted combination of the first, second, and third output signals, wherein dynamic changing ambient light is removed as a result of the weighted combination of the first, second, and third output signals. - View Dependent Claims (24, 25)
-
Specification