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1. (WO2017151648) BIO-SENSING DEVICE WITH AMBIENT LIGHT CANCELLATION

Pub. No.:    WO/2017/151648    International Application No.:    PCT/US2017/019994
Publication Date: Sat Sep 09 01:59:59 CEST 2017 International Filing Date: Wed Mar 01 00:59:59 CET 2017
IPC: G01D 18/00
A61B 5/024
Applicants: TEXAS INSTRUMENTS INCORPORATED
TEXAS INSTRUMENTS JAPAN LIMITED
Inventors: AHMED, Hussam
VENKATARAMAN, Jagannathan
OSWAL, Sandeep, Kesrimal
AROUL, Antoine, Lourdes Praveen
TIPPANA, Hari, Babu
UDUPA, Anand, Hariraj
Title: BIO-SENSING DEVICE WITH AMBIENT LIGHT CANCELLATION
Abstract:
In described examples, a bio-sensing device (100) calibrates a time period used to make bio-physical measurements. The device (100) initiates a light source sense phase followed by a first ambient sense phase and a second ambient sense phase. In the light source sense phase, the device (100) is configured to receive a digital value indicative of current through a photodetector (122) while a light source circuit (120) is enabled. In each of the first and second ambient sense phases, the device (100) is configured to receive digital values while the light source circuit (120) is disabled. The device (100) iteratively varies the time period between the phases until the digital value received during the first ambient sense phase is within a threshold of the digital value received during the second ambient sense phase. It then applies the same time separation between the light source sense phase and the ambient phase to equalize the magnitude of the ambient light in the two phases.