NFC accessory detection without magnetometer
AssigneeSTMicroelectronics International N.V.
InventorsAlexandre Tramoni, Remy Ferroul
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Abstract
The present description relates to a mobile device comprising a near-field communication router and an antenna, coupled to the router via at least one impedance matching circuit between at least two impedance values. A first impedance value is selected to communicate with a near-field communication device of a first type in the presence of a near-field communication device of a second type, and a second impedance value is selected to communicate with a near-field communication device of the first type in the absence of a near-field communication device of the second type. The presence or the absence of a near-field communication device of the second type is determined based on polling frames transmitted by the antenna.
Claims25
A mobile device comprising:
- an antenna;
- at least one impedance matching circuit coupled to the antenna;
- and
- a near-field communication (NFC) router coupled to the at least one impedance matching circuit, and configured to:
- determine a presence or an absence of an NFC device of a second type based on polling frames transmitted by the antenna, the second type durably associable with the mobile device;
- control the at least one impedance matching circuit to select a first impedance value to communicate with an NFC device of a first type in the presence of the NFC device of the second type, wherein the NFC device of the first type and the NFC device of the second type are different devices;
- and
- control the at least one impedance matching circuit to select a second impedance value to communicate with the NFC device of the first type in the absence of the NFC device of the second type.
A method of near-field communication (NFC) of a mobile device comprising an NFC router, an antenna, and at least one impedance matching circuit coupling the NFC router and the antenna, the method comprising:
- determining a presence of an NFC device of a second type based on first polling frames transmitted by the antenna, the second type durably associable with the mobile device;
- selecting a first impedance value to communicate with an NFC device of a first type in the presence of the NFC device of the second type, the NFC device of the first type and the NFC device of the second type being different devices;
- determining an absence of the NFC device of the second type based on second polling frames transmitted by the antenna;
- and
- selecting a second impedance value to communicate with the NFC device of the first type in the absence of the NFC device of the second type.
A system comprising:
- a mobile device comprising:
- an antenna;
- at least one impedance matching circuit coupled to the antenna;
- and
- a near-field communication (NFC) router coupled to the at least one impedance matching circuit, and configured to:
- determine a presence or an absence of an NFC device of a second type based on polling frames transmitted by the antenna, the second type durably associable with the mobile device;
- control the at least one impedance matching circuit to select a first impedance value to communicate with an NFC device of a first type in the presence of the NFC device of the second type, wherein the NFC device of the first type and the NFC device of the second type are different devices;
- and
- control the at least one impedance matching circuit to select a second impedance value to communicate with the NFC device of the first type in the absence of the NFC device of the second type;
- the NFC device of the first type;
- and
- the NFC device of the second type.
Dependencies are inferred from the claim text.