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US 9,853,677 B2Granted
Method for controlling the tuning to a communications frequency of an antenna connected to a component designed for contactless communication and corresponding system
AssigneeSTMicroelectronics (Rousset) SAS
InventorAlexandre Tramoni
Life of this patent
Estimating the term…
Abstract
A system includes an antenna, and a contactless component for receiving and/or transmitting information via the antenna according to a contactless communications protocol. An inductive-capacitive network is connected between the antenna and the contactless component and includes a configurable filter for filtering electromagnetic interference. A processor modifies an impedance of the configurable filter for filtering electromagnetic interference to control frequency tuning of the antenna.
Claims32
A system comprising:
- an antenna;
- a contactless component configured for exchanging information via the antenna according to a contactless communications protocol;
- a configurable filter coupled between the antenna and the contactless component, the configurable filter configured to filter electromagnetic interference and is configurable to one of a plurality of filtering configurations that all have a cut-off frequency that is substantially the same and wherein the configurable filter comprises a reference inductance and a reference capacitive value associated with the reference cut-off frequency;
- and
- a controller configured to modify an impedance of the configurable filter for filtering electromagnetic interference to control frequency tuning of the antenna by selecting one of the plurality of filtering configurations;
- wherein the configurable filter comprises a configurable inductive-capacitive circuit coupled between the contactless component and terminals of said antenna and a configurable capacitive circuit coupled between said configurable inductive-capacitive circuit and a neutral point;
- wherein the configurable inductive-capacitive circuit comprises a first set of switchable auxiliary capacitive circuits, and an inductive-capacitive module configurable by the first set of switchable auxiliary capacitive circuits;
- wherein the configurable capacitive circuit comprises a second set of switchable auxiliary capacitive circuits, and a capacitive module configurable by the second set of switchable auxiliary capacitive circuits;
- and
- wherein, in each filtering configuration, an impedance of the configurable inductive-capacitive circuit at the reference cut-off frequency is equal to the reference inductance, and an impedance of the configurable capacitive circuit at the reference cut-off frequency is equal to the reference capacitive value.
7 more elements
An apparatus comprising:
- a contactless component having a first output terminal, a second output terminal, a first auxiliary terminal, and a second auxiliary terminal;
- a configurable inductive-capacitive circuit coupled to the contactless component, the configurable inductive-capacitive circuit comprising:
- a first main inductive element having a first input coupled to the first output terminal of the contactless component and a second input coupled to the first auxiliary terminal of the contactless component;
- a second main inductive element having a first input coupled to the second output terminal of the contactless component and a second input coupled to the second auxiliary terminal of the contactless component;
- a first main capacitor coupled in parallel to the first main inductive element;
- a second main capacitor coupled in parallel to the second main inductive element;
- a first plurality of switchable auxiliary capacitors, wherein each of the first plurality of switchable auxiliary capacitors is coupled between the first auxiliary terminal and the first output terminal of the contactless component;
- and
- a second plurality of switchable auxiliary capacitors, wherein each of the second plurality of switchable auxiliary capacitors is coupled between the first auxiliary terminal and a neutral point;
- a third plurality of switchable auxiliary capacitors, wherein each of the third plurality of switchable auxiliary capacitors is coupled between the second auxiliary terminal and the second output terminal of the contactless component;
- and
- a fourth plurality of switchable auxiliary capacitors, wherein each of the fourth plurality of switchable auxiliary capacitors is coupled between the second auxiliary terminal and the neutral point.
9 more elements
An antenna frequency tuning system comprising:
- a contactless component configured to exchange information in accordance with a contactless communications protocol;
- a configurable inductive-capacitive circuit configured for impedance matching at a resonant frequency of an antenna, the configurable inductive-capacitive circuit comprising:
- a first and second main inductive element configured to form a reference inductive value in accordance with the resonant frequency;
- and
- a first and second main capacitor, wherein the first main capacitor is configured in a parallel resonant circuit with the first main inductive element, and wherein the second main capacitor is configured in a parallel resonant circuit with the second main inductive element;
- a first set of auxiliary capacitive circuits comprising a first plurality of switchable auxiliary capacitors configured in accordance with a resonant frequency of the configurable inductive-capacitive circuit, equivalent to the resonant frequency, wherein a first subset of the first plurality of switchable auxiliary capacitors are configured in a parallel resonant circuit with the first main inductive element, and wherein a second subset of the first plurality of switchable auxiliary capacitors are configured in a parallel resonant circuit with the second main inductive element;
- and
- a second set of auxiliary capacitive circuits comprising a second plurality of switchable auxiliary capacitors configured in accordance with the first set of auxiliary capacitive circuits.
5 more elements
A method of impedance matching an antenna connected to a contactless component by a configurable inductive-capacitive parallel resonant circuit, the method comprising:
- determining an impedance mismatch between the contactless component and the antenna;
- configuring a first plurality of switches in a first set of auxiliary capacitive circuits of the configurable inductive-capacitive parallel resonant circuit in accordance with a resonant frequency equivalent to a carrier frequency;
- and
- configuring a second plurality of switches in a second set of auxiliary capacitive circuits in accordance with the configuring of the first plurality of switches in the first set of auxiliary capacitive circuits.
1 more element
Dependencies are inferred from the claim text.