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US 11,029,200 B2Granted
Ambient luminosity level detection
AssigneeSTMicroelectronics (Grenoble 2) SAS
InventorPascal Mellot
Life of this patent
Estimating the term…
Abstract
The following steps are performed in connection with a photodiode circuit: a) resetting the photodiode circuit; b) determining when a photodiode voltage changes in response to illumination to reach a threshold; and c) updating a counter in response to the determination in step b). The steps a) to c) are repeated until an end of a measurement period is reached. The value of the counter at the end of the measurement period is then output to indicate an intensity of the illumination.
Claims18
A method, comprising:
- a) resetting a photodiode;
- b) determining when a photodiode voltage changes in response to illumination to reach a threshold;
- c) updating a counter in response to the determination in step b);
- d) repeating steps a) to c) until an end of a measurement period is reached;
- and
- e) outputting a value of the counter at the end of the measurement period that is indicative of an intensity of said illumination;
- wherein a difference between a time for resetting the photodiode and a time when the threshold is reached is a discharge time;
- and
- wherein the measurement period expires when a sum of a plurality of consecutive discharge times equals or exceeds a threshold period.
6 more elements
A method, comprising:
- a) sensing a discharge of a photodiode;
- b) in response to said sensing:
- triggering an updating of a counter storing a count value and resetting the photodiode;
- c) measuring a discharge time of the photodiode after resetting of the photodiode;
- d) repeating steps a) to c) over a time interval;
- and
- e) outputting a light intensity received by the photodiode as said count value of the counter at an end of the time interval;
- wherein the time interval is equal to a sum of a plurality of discharge times for said photodiode.
5 more elements
A method, comprising:
- a) generating by a photodiode of a voltage which changes at a rate dependent on illumination;
- b) comparing the voltage to a reference;
- c) incrementing a count value in response to said comparison and resetting the photodiode;
- repeating steps a) to c) until a measurement period expires;
- and
- outputting the count value at an end of the measurement period as being indicative of an intensity of said illumination;
- wherein a difference between a time for resetting the photodiode and a time for the compared voltage to pass the reference change is a discharge time, and wherein the measurement period expires when a sum of a plurality of consecutive discharge times equals or exceeds a threshold period.
4 more elements
Dependencies are inferred from the claim text.