Nxp B.v.

Leonhard Kormann

Markus Wobak

Fred George Nunziata

Gernot Hueber

Ian Thomas Macnamara

Juergen Schroeder

Aspects of the disclosure are directed to auto-sweeping impedance-matching circuitry that matches an impedance of an RF antenna. As may be implemented in accordance with one or more embodiments, a transmitter that is configured and arranged to transmit signals to remote devices via the RF antenna, is used to communicate a plurality of test signals to the impedance-matching circuitry, with each test signal having a designated frequency and/or test signal pattern that is different than the designated frequency and/or test signal pattern of the other test signals. A characteristic of each of the test signals as passed through the impedance-matching circuitry is detected. For each of the test signals generated for the auto-sweep, the detected characteristic is compared to an expected characteristic for the test signal, and an output indicative of compliance of the impedance-matching circuitry with a design specification is generated and transmitted in response to the comparison.

Methods and apparatuses for testing inductive coupling circuitry

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.

NFC system wakeup with energy harvesting

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.

NFC or RFID device RF detuning detection and driver output power regulation

A communication device is disclosed. The communication device includes a receiver, a transmitter, a memory, a sensor to measure antenna detuning, a plurality of receiver configurations stored in the memory. Each of the plurality of receiver configurations include parameter-value pairs and a control unit, coupled to the sensor and the receiver, to select a receiver configuration from the plurality of receiver configurations based on an output of the sensor. The control unit is configured to alter a processing behavior of the receiver by altering values of receiver control parameters according to the parameter-value pairs.

Load dependent receiver configuration

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.

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Gratkorn, Austria

Leonhard Kormann