Method and device for radio frequency voltage limiting

Abstract

The invention provides a method and device for Radio Frequency (RF) limiting. The device for RF limiting comprises: an Analog Limiter configured to limit a voltage of a RF input to a predetermined safe range during power-off or power-up until a disable control signal is received from the Digital Controller, a Sensing Circuit configured to sense a plurality of shunting currents provided by the Analog Limiter in sequence to determine a value of each bit of a preset current sensing code and sense the limiting voltage, a Digital Controller configured to control the Digital Limiter to perform RF limiting function based on the value of each bit of the preset current sensing code, and control the Analog Limiter to stop limiting the voltage of the RF input if the limiting voltage is within a predetermined acceptable voltage range.

Description

field of invention

[0001] The present invention relates to radio frequency (radio frequency, RF) voltage limiting, in particular to a method and device for limiting radio frequency voltage at a near-field communication front end. Background technique

[0002] Near-Field Communication (Near-Field Communication, NFC) or Radio Frequency Identification (Radio Frequency Identification, RFID) system is a short-range communication technology with a typical communication distance of 4 cm. Unlike far-field communication systems that use electromagnetic transmission, NFC uses magnetic field coupling for data exchange.

[0003] In the large dynamic range of the magnetic field, that is, 0.15A / m to 12A / m, the front end of the NFC device is in the voltage range of less than 1V to tens of volts, and there is no need for RF voltage limitation. For reliability and proper operation, the RF limiter needs to limit the RF input voltage to the NFC device to below 3.6V, which is within the reliab...

Examples

Embodiment Construction

[0026] In the following description, numerous specific details are set forth in order to provide a thorough understanding of various embodiments of the invention. However, it will be understood by those skilled in the art that embodiments of the invention may be practiced without some or all of these specific details. It should be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention. In the drawings, the same reference numerals refer to the same or similar functionality or features throughout the several views.

[0027] Embodiments of the present invention provide a solution for RF voltage limitation. This scheme utilizes the advantages of the analog limiter and the digital limiter to overcome the disadvantages of the existing RF limiter. Analog limiters with fast response are used to protect RF voltage limiting devices during power-up or during abnormal operation scen...

field of invention

[0001] The present invention relates to radio frequency (radio frequency, RF) voltage limiting, in particular to a method and device for limiting radio frequency voltage at a near-field communication front end. Background technique

[0002] Near-Field Communication (Near-Field Communication, NFC) or Radio Frequency Identification (Radio Frequency Identification, RFID) system is a short-range communication technology with a typical communication distance of 4 cm. Unlike far-field communication systems that use electromagnetic transmission, NFC uses magnetic field coupling for data exchange.

[0003] In the large dynamic range of the magnetic field, that is, 0.15A / m to 12A / m, the front end of the NFC device is in the voltage range of less than 1V to tens of volts, and there is no need for RF voltage limitation. For reliability and proper operation, the RF limiter needs to limit the RF input voltage to the NFC device to below 3.6V, which is within the reliab...

Examples

Embodiment Construction

[0026] In the following description, numerous specific details are set forth in order to provide a thorough understanding of various embodiments of the invention. However, it will be understood by those skilled in the art that embodiments of the invention may be practiced without some or all of these specific details. It should be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention. In the drawings, the same reference numerals refer to the same or similar functionality or features throughout the several views.

[0027] Embodiments of the present invention provide a solution for RF voltage limitation. This scheme utilizes the advantages of the analog limiter and the digital limiter to overcome the disadvantages of the existing RF limiter. Analog limiters with fast response are used to protect RF voltage limiting devices during power-up or during abnormal operation scen...

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