RF front end module and near field communication device

Patent metadata

Field	Value
Publication number	US-10200091-B2
Application number	US-201715621286-A
Country	US
Kind code	B2
Filing date	Jun 13, 2017
Priority date	Jun 13, 2017
Publication date	Feb 5, 2019
Grant date	Feb 5, 2019

Abstract

A device for inductively coupled communications includes an NFC module for generating an electromagnetic carrier signal and modulating the carrier signal according to data to be transmitted, and an antenna circuit coupled to and driven by said NFC module with the modulated carrier signal. The device includes an RF front end coupled between said NFC module and said antenna circuit. The RF front end includes a balanced to unbalanced (Balun) transformer and a tuning capacitor. The Balun transformer has a first winding coupled to said NFC module via differential transmitter terminals of said NFC module and a second winding coupled to said tuning capacitor. A first terminal of said tuning capacitor is coupled to a receiving terminal of said NFC module. The Balun transformer and tuning capacitor provide a function of an electromagnetic compatibility (EMC) filter.

First claim

What is claimed is:

1. A device for inductively coupled communications comprising:
a near field communication (NFC) module being adapted to generate an electromagnetic carrier signal and to modulate the carrier signal according to data to be transmitted;
an antenna circuit coupled to said NFC module and driven by said NFC module with the modulated carrier signal; and
an RF front end coupled between said NFC module and said antenna circuit;
said RF front end including a balanced to unbalanced (Balun) transformer and a tuning capacitor;
said Balun transformer having a first winding coupled to said NFC module via differential transmitter terminals of said NFC module and a second winding coupled to said tuning capacitor;
a first terminal of said tuning capacitor being coupled to a receiving terminal of said NFC module;
said Balun transformer and said tuning capacitor being adapted to provide a function of an electromagnetic compatibility (EMC) filter without using an inductor and capacitor network (LC network) coupled between said NFC module and said Balun transformer.

2. The device of claim 1 , further comprising an inductor having a first terminal connected to said second winding and a second terminal connected to said tuning capacitor.

3. The device of claim 1 , wherein said NFC module includes a differential transmitter and a single-ended receiver.

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

5. The device of claim 1 , wherein said Balun transformer has an equivalent inductance and a coupling factor K, wherein said coupling factor K has a value between 0 and 1.

6. The device of claim 1 , wherein said function of said EMC filter is a low pass filter.

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. A device for inductively coupled communications comprising:
a near field communication (NFC) module being adapted to generate an electromagnetic carrier signal and to modulate the carrier signal according to data to be transmitted;
an antenna circuit coupled to said NFC module and driven by said NFC module with the modulated carrier signal; and
an RF front end coupled between said NFC module and said antenna circuit;
said RF front end including a balanced to unbalanced (Balun) transformer;
said Balun transformer having a first winding coupled to said NFC module via differential transmitter terminals of said NFC module;
a receiving terminal of said NFC module being coupled to an input terminal of said antenna circuit;
said Balun transformer being adapted to provide a function of an electromagnetic compatibility (EMC) filter without using an inductor and capacitor network (LC network) coupled between said NFC module and said Balun transformer.

9. The device of claim 8 , further comprising a tuning capacitor coupled to a second winding of said Balun transformer, said Balun transformer and said tuning capacitor being adapted to provide said function of said EMC filter.

10. The device of claim 9 , further comprising an inductor having a first terminal connected to said second winding and a second terminal connected to said tuning capacitor.

11. The device of claim 8 , wherein said NFC module includes a differential transmitter and a single-ended receiver.

12. The device of claim 8 , wherein said antenna circuit is a single-end antenna.

13. The device of claim 8 , wherein said Balun transformer has an equivalent inductance and a coupling factor K, wherein said coupling factor K has a value between 0 and 1.

14. The device of claim 8 , wherein said function of said EMC filter is a low pass filter.

15. A device for inductively coupled communications comprising:
a near field communication (NFC) module being adapted to generate an electromagnetic carrier signal and to modulate the carrier signal according to data to be transmitted;
an antenna circuit coupled to said NFC module and driven by said NFC module with the modulated carrier signal; and
an RF front end coupled between said NFC module and said antenna circuit;
said RF front end including a balanced to unbalanced (Balun) transformer;
said Balun transformer having a first winding coupled to said NFC module via differential transmitter terminals of said NFC module and a second winding coupled to a receiving terminal of said NFC module;
said Balun transformer being adapted to provide a function of an electromagnetic compatibility (EMC) filter without using an inductor and capacitor network (LC network) coupled between said NFC module and said Balun transformer.

16. The device of claim 15 , wherein said NFC module includes a differential transmitter and a single-ended receiver.

17. The device of claim 15 , wherein said antenna circuit is a single-end antenna.

18. The device of claim 15 , wherein said Balun transformer has an equivalent inductance and a coupling factor K, wherein said coupling factor K has a value between 0 and 1.

19. The device of claim 15 , wherein said function of said EMC filter is a low pass filter.

20. The device of claim 1 , wherein said NFC module includes a differential transmitter having a first terminal and a second terminal, wherein said first winding of said Balun transformer is connected to both said first and second terminals of said differential transmitter.

Assignees

• Nxp Bv

Inventors

• Ding Jingfeng
• Hueber Gernot
• Macnamara Ian Thomas

Classifications

• H04W88/06 Primary

  adapted for operation in multiple networks {or having at least two operational modes}, e.g. multi-mode terminals · CPC title

• H04B5/0031

  Electricity · mapped topic

• H04B5/0075 Primary

  Electricity · mapped topic

• H04B5/40

  characterised by components specially adapted for near-field transmission · CPC title

• H04B5/24 Primary

  Inductive coupling · CPC title