Gain correction for multi-bit successive-approximation register
AssigneeTexas Instruments Incorporated
InventorsSrinivas Kumar Reddy Naru, Anand Jerry George, Shagun Dusad, Visvesvaraya Appala Pentakota
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Abstract
A system has a digital-to-analog converter; a reference signal coupled to the digital-to-analog converter; a differential amplifier for applying gain, and for generating output signals as a function of sampled input signals, the reference signal, digital codes, and the gain applied by the differential amplifier coupled to the digital-to-analog converter; and a multi-bit successive-approximation register for determining the digital codes in successive stages coupled to the differential amplifier; and the gain applied by the differential amplifier is corrected based on previously determined digital codes.
Claims18
A circuit comprising:
- a differential amplifier having first and second amplifier inputs, an amplifier output, and a gain correction input;
- a successive-approximation register coupled to the amplifier output, the successive-approximation register including:
- an analog-to-digital converter coupled to the amplifier output;
- and
- an encoder coupled to the analog-to-digital converter and having a digital code output;
- and
- gain correction circuitry having:
- an input coupled to the digital code output;
- and an output coupled to the gain correction input of the differential amplifier, the gain correction circuitry configured to:
- receive a digital code from the encoder;
- and
- determine a gain correction value using the digital code, the gain correction value to adjust a gain of the differential amplifier.
A method comprising:
- receiving a sample of an analog voltage and receiving a first comparison signal into an amplifier;
- generating an amplifier output signal by the amplifier based on the sample of the analog voltage, the first comparison signal, and a gain of the amplifier;
- generating a digital approximation code in a successive-approximation register using the amplifier output signal;
- generating an output digital code using the digital approximation code, the output digital code representing the sample of the analog voltage;
- determining a gain adjustment value using the digital approximation code;
- adjusting the gain of the amplifier based on the gain adjustment value;
- and
- generating a second comparison signal using the digital approximation code.
A circuit comprising:
- a differential amplifier having first and second amplifier inputs, an amplifier output, and a gain correction input;
- a successive-approximation register coupled to the amplifier output and having a digital code output;
- a digital-to-analog converter having:
- a first input coupled to the digital code output of the successive-approximation register;
- a second input;
- and an output coupled to the first amplifier input;
- a sample-and-hold circuit having a respective output coupled to the second amplifier input;
- and
- gain correction circuitry having:
- a respective input coupled to the digital code output of the successive-approximation register;
- and a respective output coupled to the gain correction input of the differential amplifier, the gain correction circuitry configured to:
- receive a digital code from the successive-approximation register;
- and
- determine a gain correction value using the digital code, the gain correction value to adjust a gain of the differential amplifier.
Dependencies are inferred from the claim text.