Nfc demodulation circuit
AssigneeSTMicroelectronics International N.V.
InventorsFranck MONTAUDON, Mounir BOULEMNAKHER, Julien GOULIER
Life of this patent
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Abstract
An amplification circuit includes an amplifier circuit (provided by an operational amplifier) that amplifies a signal to be demodulated. A feedback loop of the amplification circuit has a resistance value that is controlled to discretely vary according to a level of an output node of the amplifier circuit. A comparison of the output level with respect to one or a plurality of thresholds, which define out-of-saturation operating ranges of the amplifier circuit, drives selection of the resistance value.
Claims21
An amplification circuit, comprising:
- an amplifier circuit including an operational amplifier, said amplifier circuit configured to amplify a signal to be demodulated;
- and
- a feedback loop having a resistance value discretely varying according to a level of an output node of said amplifier circuit with respect to one or a plurality of thresholds defining one or a plurality of out-of-saturation operating ranges of the amplifier circuit.
An amplification circuit, comprising:
- an amplifier circuit configured to amplify a signal to be demodulated;
- and
- a feedback loop coupled between and input node and output node of the amplifier circuit;
- wherein the feedback loop has a resistance value discretely varying according to a level at the output node of said amplifier circuit with respect to one or a plurality of thresholds defining one or a plurality of out-of-saturation operating ranges of the amplifier circuit;
- wherein the resistance value of the feedback loop of the amplifier circuit is controlled to have a first resistance value when said level is higher than a first threshold or when said level is lower than a second threshold, where the second threshold is lower than the first threshold;
- and
- wherein said feedback loop comprises:
- a first branch coupling the input node of the amplifier circuit to the output node, said first branch including a resistive element having a first resistance value;
- N additional branches coupled in parallel with the first branch, wherein each additional branch includes a resistive element in series with a switch controlled by a respective control signal, N being a positive integer greater than two;
- said respective control signal being dependent on a comparison between the level of the output node of said amplifier circuit with respect to a respective operating range from among N out-of-saturation operating ranges of the amplifier circuit, each operating range being defined by thresholds;
- and
- N comparison circuits configured to generate a respective control signal for each of the N additional branches to make the respective switch:
- non-conductive when the level of the output node of the amplifier circuit is in the respective operating range;
- and
- conductive when the level of the output node of the amplifier circuit is outside of said respective operating range.
Dependencies are inferred from the claim text.