Near field communication device

• US 10,361,474 B2
• Filed: 03/17/2017
• Issued: 07/23/2019
• Est. Priority Date: 03/17/2017
• Status: Active Grant

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: NXP B.V. (NXP Semiconductors NV)
• Inventors: Ding, Jingfeng, Al-kadi, Ghiath, Merlin, Erich
• Primary Examiner(s): Tran, Hai V
• Application Number:
  US15/462,757
• Publication Number:
  US 20180269560A1
• Time in Patent Office: 858 Days
• Field of Search: 343702
• CPC Class Codes: G06K 19/0727 the arrangement being a circuit facilitating integration of the record carrier with a hand-held device such as a smart phone of PDA
• CPC Class Codes: G06K 7/10237 the reader and the record carrier being capable of selectively switching between reader and record carrier appearance, e.g. in near field communication [NFC] devices where the NFC device may function as an RFID reader or as an RFID tag
• CPC Class Codes: H01Q 1/2216 used in interrogator/reader equipment
• CPC Class Codes: H01Q 1/243 with built-in antennas
• CPC Class Codes: H01Q 1/50 Structural association of antennas with earthing switches, lead-in devices or lightning protectors
• CPC Class Codes: H01Q 3/26 varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture H01Q3/12, H01Q3/22, H01Q3/24 take precedence
• CPC Class Codes: H04B 5/24 Inductive coupling
• CPC Class Codes: H04B 5/72 for local intradevice communication
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

A near field communication (NFC) device capable of operating by being powered by the field includes an NFC module for generating an electromagnetic carrier signal and modulating the carrier signal, and an antenna circuit coupled to and driven by said NFC module with the modulated carrier signal. A differential power combiner circuit is coupled to said NFC module via output terminals of said NFC module. A powered by the field circuit of the NFC device is adapted to harvest energy from an external field to power said NFC device. The power by the field circuit has a first terminal coupled to an output of said differential power combiner circuit via a first impedance block and a second terminal coupled to an input of said antenna circuit via a second impedance block. The NFC device is adapted to be able to operate in a powered by the field card mode.

Claims

1. A device, for contactless communication comprising:

an NFC module being adapted to generate an electromagnetic carrier signal and to modulate the carrier signal according to data to be transmitted;

a differential power combiner circuit coupled to said NFC module via output terminals of said NFC module; and

an antenna circuit coupled to and driven by said NFC module with the modulated carrier signal;

said NFC module comprising a power by the field (PBF) circuit adapted to harvest energy from an external field to power said device;

said power by the field circuit having a first terminal coupled to an output of said differential power combiner circuit via a first impedance block and a second terminal coupled to an input of said antenna circuit via a second impedance block;

said device being adapted to be able to operate in a power by the field card mode;

wherein said first impedance block includes a first impedance element internal to the NFC module and a second impedance element external to the NFC module, said first and second impedance elements being arranged in series;

wherein said second impedance block includes a third impedance element internal to the NFC module and a fourth impedance element external to the NFC module, said third and fourth impedance elements being arranged in series;

wherein said first impedance element is further coupled to a first switch, said first impedance element and said first switch being arranged in parallel; and

wherein said third impedance element is further coupled to a second switch, said third impedance element and said second switch being arranged in parallel.

2. The device of claim 1, wherein said first and second switches are configured to be closed when said device operates in the powered by the field card mode.

3. The device of claim 1, wherein said first and second switches are configured to be open when said device operates in a reader mode.

4. The device of claim 1, wherein said antenna circuit is a single end antenna.

5. The device of claim 1, wherein said device has a single end antenna matching topology and does not use a balanced to unbalanced (Balun) transformer.

7. The device of claim 1, wherein said device is incorporated in a mobile device and adapted to be powered by the mobile device.

8. The device of claim 1, wherein said device is further adapted to be able to operate in a reader mode.

9. The device of claim 1, wherein said device is adapted to perform active load modulation (ALM) in a card mode.

10. The device of claim 1, wherein said device is adapted to perform passive load modulation (PLM) in the power by the field card mode.

6. The device of 1, further comprising one or more tuning capacitors for tuning phases of incoming signals to the NFC module.

11. A device for contactless communication comprising:

an NFC module being adapted to generate an electromagnetic carrier signal and to modulate the carrier signal according to data to be transmitted;

a differential power combiner circuit coupled to said NFC module via output terminals of said NFC module; and

an antenna circuit coupled to and driven by said NFC module with the modulated carrier signal;

said NFC module comprising a power by the field (PBF) circuit adapted to harvest energy from an external field to power said device;

said power by the field circuit having a first terminal coupled to an output of said differential power combiner circuit via a first impedance block and a second terminal coupled to an input of said antenna circuit via a second impedance block;

said device being adapted to be able to operate in a power by the field card mode;

wherein said first impedance block includes a first impedance element external to the NFC module;

wherein said second impedance block includes a second impedance element external to the NFC module;

wherein said first impedance element is further connected in series to a first switch, said first switch being internal to the NFC module; and

wherein said second impedance element is further connected in series with a second switch, said second switch being internal to the NFC module.

12. A device for contactless communication comprising:

an NFC module being adapted to generate an electromagnetic carrier signal and to modulate the carrier signal according to data to be transmitted;

a differential power combiner circuit coupled to said NFC module via output terminals of said NFC module; and

an antenna circuit coupled to and driven by said NFC module with the modulated carrier signal;

said NFC module comprising a power by the field (PBF) circuit adapted to harvest energy from an external field to power said device;

said power by the field circuit having a first terminal coupled to an output of said differential power combiner circuit via a first impedance block and a second terminal coupled to an input of said antenna circuit via a second impedance block;

said device being adapted to be able to operate in a power by the field card mode;

wherein said differential power combiner circuit is a differential LC power combiner circuit comprising an inductor and a capacitor connected in series;

wherein a capacitor and an inductor are arranged in series between said output of said differential power combiner circuit and said input of said antenna circuit.

13. The device of claim 12,

wherein said first impedance block includes a first impedance element internal to the NFC module and a second impedance element external to the NFC module, said first and second impedance elements being arranged in series;

and

wherein said second impedance block includes a third impedance element internal to the NFC module and a fourth impedance element external to the NFC module, said third and fourth impedance elements being arranged in series.

14. The device of claim 13,

wherein said first impedance element is further coupled to a first switch, said first impedance element and said first switch being arranged in parallel;

and

wherein said third impedance element is further coupled to a second switch, said third impedance element and said second switch being arranged in parallel.

15. The device of claim 12,

wherein said first impedance block includes a first impedance element external to the NFC module;

and

wherein said second impedance block includes a second impedance element external to the NFC module.

16. The device of claim 15,

wherein said first impedance element is further connected in series to a first switch, said first switch being internal to the NFC module;

and

wherein said second impedance element is further connected in series with a second switch, said second switch being internal to the NFC module.

17. The device of claim 12, wherein said antenna circuit is a single end antenna.

18. The device of claim 12, wherein said device has a single end antenna matching topology and does not use a balanced to unbalanced (Balun) transformer.

19. The device of claim 12, wherein said device is adapted to perform active load modulation (ALM) in a card mode.

20. The device of claim 12, wherein said device is adapted to perform passive load modulation (PLM) in the power by the field card mode.