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US 11,143,553 B2Granted
Method to operate an optical sensor arrangement with improved offset correction and optical sensor arrangement
Assigneeams International AG
InventorsLouis Albert Williams, III, Gonggui Xu
Life of this patent
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Abstract
An optical sensor arrangement comprises a photodiode and a converter arrangement including an integration amplifier, a comparator amplifier, an integration capacitor and a comparator capacitor. An offset of the integration amplifier is corrected in that the integrator output signal is compared with a high and a low comparison voltage to repetitively adjust an offset trim value. The use of two comparison thresholds creates noise immunity.
Claims18
A method to operate an optical sensor arrangement,
- the optical sensor arrangement comprising:
- a photodiode;
- a converter arrangement, comprising:
- an integration amplifier and a comparator amplifier, the integration amplifier having an offset;
- an integration capacitor coupled to an input of the integration amplifier;
- a comparator capacitor coupled to an input of the comparator amplifier;
- an offset register to control the offset of the integration amplifier in response to an offset trim value stored in the offset register;
- the photodiode decoupled from the input side of the first amplifier;
- a controller to operate the converter arrangement;
- the method comprising performing a multitude of offset reduction loops, wherein the integration capacitor is connected to the integration amplifier to form an integrator or is connected to the output of the comparator amplifier or is open ended,
- each loop comprising the steps of:
- shorting the inputs of the integration amplifier to ground potential;
- sampling a reference voltage on the integration capacitor;
- applying one of a high and a low comparison voltage to the comparator capacitor;
- comparing an integrator output signal with the one of the comparison voltages at the comparator amplifier;
- applying another one of the high and the low comparison voltages to the comparator capacitor;
- comparing the integrator output signal with the other one of the comparison voltages at the comparator amplifier;
- and
- adjusting the offset trim value in response to one of the steps of comparing.
16 more elements
An optical sensor arrangement, comprising:
- a photodiode;
- a converter arrangement, comprising:
- an integration amplifier and a comparator amplifier, the integration amplifier having an offset;
- an integration capacitor coupled to an input of the integration amplifier;
- a comparator capacitor coupled to an input of the comparator amplifier;
- an offset register to control the offset of the integration amplifier in response to an offset trim value stored in the offset register;
- the photodiode to be coupled to the input side of the first amplifier;
- a controller to generate control signals operate the converter arrangement through a multitude of offset correction loops,
- wherein the converter arrangement is configured to adopt a configuration in response to the control signals generated by the controller, the configuration selected from the group comprising a high gain initialization configuration, a high gain idle configuration, an open loop measure configuration, an open loop amplify configuration and an open loop compare configuration,
- wherein the converter arrangement is configured to perform a consecutive sequence of two or more of said configurations to achieve an offset reduction of the integration amplifier.
7 more elements
A mobile computing device comprising an optical sensor arrangement and a display screen, the optical sensor arrangement comprising:
- a photodiode;
- a converter arrangement, comprising:
- an integration amplifier and a comparator amplifier, the integration amplifier having an offset;
- an integration capacitor coupled to an input of the integration amplifier;
- a comparator capacitor coupled to an input of the comparator amplifier;
- an offset register to control the offset of the integration amplifier in response to an offset trim value stored in the offset register;
- the photodiode to be coupled to the input side of the first amplifier;
- a controller to generate control signals operate the converter arrangement through a multitude of offset correction loops,
- wherein the converter arrangement is configured to adopt a configuration in response to the control signals generated by the controller, the configuration selected from the group comprising a high gain initialization configuration, a high gain idle configuration, an open loop measure configuration, an open loop amplify configuration and an open loop compare configuration,
- wherein the converter arrangement is configured to perform a consecutive sequence of two or more of said configurations to achieve an offset reduction of the integration amplifier,
- wherein the optical sensor arrangement comprises an output terminal to supply a signal indicative of ambient light and wherein the brightness of the display screen is controlled in dependence on the signal indicative of ambient light generated by the light sensor arrangement.
8 more elements
Dependencies are inferred from the claim text.