公开(公告)号：US10164600B2

公开(公告)日：2018-12-25

申请号：US14881095

申请日：2015-10-12

Applicant: NXP B.V.

Inventor： Leonhard Kormann ,  Markus Wobak ,  Fred George Nunziata

IPC: G06K7/10 ,  H03H7/38 ,  H04B5/00

Abstract: A near field communication (NFC) or Radio Frequency Identification (RFID) reader device for contact-less communication includes a transmitter block connected to an antenna via a matching circuitry. An electromagnetic carrier signal and modulated data information are emitted via this main antenna. Any secondary object brought into the vicinity of the main antenna influences the primary resonant circuit resulting in a load change seen by the transmitter. This detuning can cause increased power consumption, RF (Radio Frequency) standard incompliance, and device damage. The present disclosure describes devices and methods on how to detect detuning and how to regulate the transmitter's output.

公开(公告)号：US20180034507A1

公开(公告)日：2018-02-01

申请号：US15225759

申请日：2016-08-01

Applicant: NXP B.V.

Inventor： Markus Wobak ,  Leonhard Kormann ,  Juergen Schroeder

IPC: H04B5/00

Abstract: The present invention provides for a system that makes use of a system power supply enable switch controlled by a near field communications (NFC) frontend with energy harvesting. In one embodiment, RF power in the 13.56 MHz band generated by a NFC counterpart (such as a mobile phone) is detected by the energy harvesting unit being part of the battery-unpowered NFC communication device. After activation, the system can perform actions required to communicate to the presented device (i.e., the NFC counterpart). Later, the system can switch itself into the unpowered state again. In another embodiment, this feature can also be used to control an NFC protection circuitry very quickly after the NFC device is exposed to an external HF (high frequency) field.

公开(公告)号：US09654181B1

公开(公告)日：2017-05-16

申请号：US14968788

申请日：2015-12-14

Applicant: NXP B.V.

Inventor： Markus Wobak ,  Leonhard Kormann ,  Fred George Nunziata

IPC: H04B5/00

CPC classification number: H04B5/0031 ,  H04B5/0037 ,  H04B5/0075 ,  H04B17/101

Abstract: Transmitter (TX) modulation envelope parameters are defined in RF standards (e.g., ISO 14443, NFC Forum, EMVCo). These envelope parameters include rise/fall times, modulation index, etc. For standards compliancy, these envelope parameters must be within the respective limits. For example, shaping parameters are influenced by detuning the antenna with a counterpart device like a card or mobile phone, or by thermal influences on the matching network. This disclosure describes an NFC or RFID device that is able to detect and measure the detuning on the antenna and/or the matching network change. With this information, the NFC or RFID device can dynamically control the shaping parameters of the envelope, instead of relying on one single static configuration setting for the transmitter. In particular, changes in the Q (quality) factor are used for dynamically controlling the transmitter signal envelope shape for compensating the effect of antenna detuning and/or matching network variation.