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US 12,542,559 B2Granted
Offset calibration for an analog front-end system variable-gain amplifier
AssigneeSTMicroelectronics International N.V.
InventorsAnkur Bal, Anubhuti Chopra
Life of this patent
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Abstract
Offset calibration for an analog front-end system is provided. The analog front-end system includes a variable-gain amplifier, and the calibration mitigates an offset error of the variable-gain amplifier. Calibration is based on a difference-based estimation technique combined with digital iteration. Difference-based estimation includes measuring different digital output signals from an analog-to-digital converter for different respective gains of the variable-gain amplifier. The digital iteration is utilized to estimate offsets values which converge a digital output difference to a target of zero volts.
Claims20
An analog front-end system, comprising:
- a variable-gain amplifier having:
- an input configured to receive an analog signal;
- a gain control input;
- a DC offset control input;
- and
- an output;
- an analog-to-digital converter having an input coupled to the output of the variable-gain amplifier and an output configured to provide a digital signal;
- and
- a controller configured to calibrate the variable-gain amplifier by at least:
- setting, via the gain control input of the variable-gain amplifier, a gain of the variable-gain amplifier to a first gain value;
- in response to setting the gain to the first gain value, determining a first digital signal output by the analog-to-digital converter;
- setting, via the gain control input of the variable-gain amplifier, the gain of the variable-gain amplifier to a second gain value;
- in response to setting the gain to the second gain value, determining a second digital signal output by the analog-to-digital converter;
- determining a difference between the first digital signal and the second digital signal;
- and
- setting, via the DC offset control input of the variable-gain amplifier, a compensating offset of the variable-gain amplifier based on the difference between the first digital signal and the second digital signal.
13 more elements
A method, comprising:
- setting, by a controller, a gain of a variable-gain amplifier of an analog front-end system to a first gain value via a gain control input of the variable-gain amplifier;
- in response to setting the gain to the first gain value, determining a first digital signal output by an analog-to-digital converter of the analog front-end system;
- setting the gain of the variable-gain amplifier to a second gain value via the gain control input of the variable-gain amplifier;
- in response to setting the gain to the second gain value, determining a second digital signal output by the analog-to-digital converter;
- determining a difference between the first digital signal and the second digital signal;
- and
- setting, via a DC offset control input of the variable-gain amplifier, a compensating offset of the variable-gain amplifier based on the difference between the first digital signal and the second digital signal.
4 more elements
A controller for an analog front-end system, comprising:
- a gain output configured to output a gain to a variable-gain amplifier of the analog front-end system;
- an offset output configured to output a compensating offset to the variable-gain amplifier, wherein the controller is configured to calibrate the variable-gain amplifier by at least:
- setting a gain of the variable-gain amplifier to a first gain value via a gain control input of a variable-gain amplifier;
- outputting the first gain value over the gain output;
- in response to outputting the first gain value, determining a first digital signal output by an analog-to-digital converter;
- setting the gain of the variable-gain amplifier to a second gain value via the gain control input of a variable-gain amplifier;
- outputting the second gain value over the gain output;
- in response to outputting the second gain value, determining a second digital signal output by the analog-to-digital converter;
- determining a difference between the first digital signal and the second digital signal;
- setting, via a DC offset control input of the variable-gain amplifier, a compensating offset of the variable-gain amplifier based on the difference between the first digital signal and the second digital signal;
- and
- outputting the compensating offset over the offset output.
9 more elements
Dependencies are inferred from the claim text.