WO1999043096A1 - Data communications terminal and method of adjusting a power signal generated therefrom - Google Patents
Data communications terminal and method of adjusting a power signal generated therefrom Download PDFInfo
- Publication number
- WO1999043096A1 WO1999043096A1 PCT/US1998/027003 US9827003W WO9943096A1 WO 1999043096 A1 WO1999043096 A1 WO 1999043096A1 US 9827003 W US9827003 W US 9827003W WO 9943096 A1 WO9943096 A1 WO 9943096A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- power
- node
- data communications
- communications terminal
- circuit
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K19/00—Record carriers for use with machines and with at least a part designed to carry digital markings
- G06K19/06—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
- G06K19/067—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
- G06K19/07—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips
- G06K19/0701—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips at least one of the integrated circuit chips comprising an arrangement for power management
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/59—Responders; Transponders
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K19/00—Record carriers for use with machines and with at least a part designed to carry digital markings
- G06K19/06—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
- G06K19/067—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
- G06K19/07—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips
- G06K19/0701—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips at least one of the integrated circuit chips comprising an arrangement for power management
- G06K19/0715—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips at least one of the integrated circuit chips comprising an arrangement for power management the arrangement including means to regulate power transfer to the integrated circuit
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
- G06K7/0008—General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
Definitions
- the invention relates generally to a data communication system and in particular to a data communication terminal and method for automatically adjusting a power level in response to a detected change in the data communications terminal.
- Data communication systems are well known and include a terminal device that communicates with a portable data device in either a contacted or contactless mode. Delivering power from the terminal device to the portable data device in a contacted arrangement is rather easily controlled through the electrical connections of the contact points. In a contactless environment, power delivery and regulation can be a more complex problem. In particular, it is imperative that the portable data device receives enough energy to maintain a suitable power level for the card circuitry, but not too much power so that the device circuitry begins to overheat. To help explain the dynamics of a card receiving too much power,
- the card can be separated from the reader. At this distance, the card sees the maximum power that can be tolerated by the circuitry on the card. When the card moves closer to the reader, the excess power must be absorbed by any number of known means, such as resistive elements, etc. When the card and reader are separated by a distance shown in region 116, the card must continually absorb the excess power so that the card circuitry is not damaged. Of course, power absorbed in resistive elements generates heat, which can build up and cause deleterious effects on the card substrate (usually some form of plastic). Likewise, as the card moves away from the reader, as depicted in region 118, the power seen by the card decreases to a minimal acceptable level 120 at a maximum allowable distance 122.
- a data communication system terminal and method for adjusting a power level for delivery to a portable data device there exists a need for a data communication system terminal and method for adjusting a power level for delivery to a portable data device.
- a data terminal that could automatically adjust the power level without requiring communications between the card and reader (e.g., a request from the card to adjust the power level) would be an improvement over the prior art.
- FIG. 1 -1 shows a data communication system, as is known in the art
- FIG. 1 -2 shows a power curve that relates detected power levels with distance between the terminal and portable data devices shown in FIG. 1 -1 ;
- FIG. 2 shows more detailed diagram of a terminal device, in accordance with the present invention
- FIG. 3 shows a simplified schematic diagram of a power delivery mechanism, in accordance with one embodiment of the present invention
- FIG. 4 shows a simplified schematic diagram showing several impedance detection techniques, in accordance with the present invention
- FIG. 5 shows a simplified schematic diagram depicting a power regulation circuit, in accordance with the invention.
- FIG. 6 shows a data flow diagram depicting operation of a terminal device, in accordance with the present invention.
- the present invention encompasses an apparatus and method for use in a data communications terminal that includes an antenna for delivering a power signal to a portable data device.
- the data communications terminal monitors an impedance characteristic for the antenna, attempting to detect a change in the monitored impedance characteristic thereof. When a change is detected, the data communications terminal automatically adjusts a power level of the power signal delivered to the portable data device.
- the present invention allows for a communication-less means by which the power delivered to the card can be adjusted by the terminal (i.e., without the need for the reader requesting a power adjustment).
- FIG. 2 shows a simplified block diagram of a data communications terminal 102, in accordance with the present invention.
- a power amplifier 201 generates and delivers a power signal to the antenna circuit 106, for transmission to the portable data device.
- the antenna circuit 106 delivers impedance characteristic information to a monitoring circuit 203, which can be implemented in a number of different ways, as later described.
- the monitoring circuit 203 is operably coupled to a power adjustment circuit 205, in accordance with the present invention.
- the power adjust circuit 205 generates a control signal 207 that is inputted to the power amplifier 201.
- the foregoing simplified elements are used to advantageously provide power adjustment without an attendant need to receive a command from the portable data device. Accordingly, it is not necessary that the card and the reader be in communication for a power adjustment to be made FIG.
- FIG. 3 shows a balanced transmitter circuit that can be used in the power amplifier 201 shown in FIG. 2.
- the power amplifiers 201 -1 and 201 -2 are driven by opposite-polarity input signals 302 and 304, such that the voltage swing across the antenna circuit 106 is double what it would be with only a single-ended, unbalanced drive circuit.
- the inductor 306 needs to be resonated, at the power amplifier carrier frequency, using resonating capacitors 308, 310 such that the maximum current is obtained through the antenna for a given drive voltage (i.e., out of the power amplifiers). Maintaining a completely balanced circuit for the antenna has the added benefit of controlling radiated emissions, as fewer spurious radiating modes are excited with an antenna that is balanced with respect to ground.
- FIG. 4 shows the antenna circuit 106 shown in FIG. 3, along with a plurality of monitoring circuits, in accordance with the present invention.
- the current through the inductor 306 is sampled using a series connected primary coil 405 of a transformer circuit, that is completed with the secondary coil 407.
- the carrier current flowing through the inductor 306 typically has a large amplitude, on the order of 0.5 amps to greater than 1 amp, in order to generate sufficient magnetic field to power a remotely coupled card.
- the sampled current is stepped down to a value appropriate for a high impedance detector circuit 409.
- the high impedance detector circuit 409 produces a control signal 410 that is proportional to the current flowing through the antenna circuit 106.
- a large turns-ratio lowers the impedance of the detector that is reflected into the primary circuit between nodes 401 and 402, thereby negligibly affecting the series losses in the antenna circuit 106. 6
- the voltage across the inductor 306 (i.e., between the two nodes 41 1 and 402) can also be sampled as a means of monitoring the impedance characteristic.
- the voltage is measured across the nodes by utilizing the inherent subtraction operation of a simple high- impedance differential amplifier 413 to produce a control signal 414.
- the voltage swing between nodes 41 1 and 402 can be very large for a high current system, on the order of 50 Vpeak, so some resistive divider or other means of reducing the voltage across the differential amplifier input nodes may be required (not shown).
- the voltage across the antenna can produce an impedance characteristic in and of itself, or when used in conjunction with the antenna series-current sense performed by 403 (or 416, as next described), an actual antenna impedance can be calculated from the sensed antenna voltage and current. It should be noted that the differential voltage measurement between nodes 41 1 and 402 does not generally provide an accurate measure of the antenna current. This is because the actual impedance seen between nodes 402 and 41 1 is dependent on the proximity of the card to the reader. However, in spite of it's inherent inaccuracy, this voltage measurement is sufficient to generate a control signal for use in a power control method, in accordance with the invention.
- a second embodiment for sampling the series current through the inductor 306 uses a monitoring circuit 416, in which a known series impedance 417 is placed between nodes 411 and 415. This impedance does not have to be resistive; a reactance or complex impedance is also useful, provided the impedance is known. By measuring the voltage drop across nodes 415- 41 1 with a high-impedance differential amplifier 419, a control signal 420 is generated that is proportional to the antenna series current.
- a preferred embodiment for the power amplifier system is shown in FIG. 5, wherein amplifier 501 may be any high-efficiency, saturated-mode amplifier. In a preferred embodiment, a class D amplifier is used.
- the card recedes from the reader the ratio again increases, and the power amplifier supply is returned to its initial level.
- FIG. 6 shows a flow diagram 600 that depicts operation of a data communications terminal in accordance with the present invention.
- the terminal monitors (601 ) its own impedance characteristic for the antenna circuit, as earlier described.
- a function of the antenna impedance, f(Z A ), is calculated (603) using one or a combination of two of the techniques earlier described.
- the impedance characteristic is continually monitored (at step 601 ).
- the power signal is adjusted (607) by a predetermined amount by the data communications terminal.
Landscapes
- Engineering & Computer Science (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- General Physics & Mathematics (AREA)
- Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Signal Processing (AREA)
- Computer Networks & Wireless Communication (AREA)
- Artificial Intelligence (AREA)
- Computer Vision & Pattern Recognition (AREA)
- Transmitters (AREA)
- Near-Field Transmission Systems (AREA)
- Transceivers (AREA)
Abstract
Description
Claims
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU20040/99A AU2004099A (en) | 1998-02-19 | 1998-12-18 | Data communications terminal and method of adjusting a power signal generated therefrom |
BR9808937-4A BR9808937A (en) | 1998-02-19 | 1998-12-18 | Data communication terminal and method of adjusting a generated strength signal from it |
EP98964796A EP0976203A4 (en) | 1998-02-19 | 1998-12-18 | Data communications terminal and method of adjusting a power signal generated therefrom |
JP54250099A JP2001520855A (en) | 1998-02-19 | 1998-12-18 | Data communication terminal and method for adjusting power signal generated by the same |
CA002287441A CA2287441A1 (en) | 1998-02-19 | 1998-12-18 | Data communications terminal and method of adjusting a power signal generated therefrom |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US2582698A | 1998-02-19 | 1998-02-19 | |
US09/025,826 | 1998-02-19 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1999043096A1 true WO1999043096A1 (en) | 1999-08-26 |
Family
ID=21828254
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1998/027003 WO1999043096A1 (en) | 1998-02-19 | 1998-12-18 | Data communications terminal and method of adjusting a power signal generated therefrom |
Country Status (9)
Country | Link |
---|---|
EP (1) | EP0976203A4 (en) |
JP (1) | JP2001520855A (en) |
KR (1) | KR20010006519A (en) |
CN (1) | CN1252908A (en) |
AU (1) | AU2004099A (en) |
BR (1) | BR9808937A (en) |
CA (1) | CA2287441A1 (en) |
TR (1) | TR199902594T1 (en) |
WO (1) | WO1999043096A1 (en) |
Cited By (29)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2804557A1 (en) * | 2000-01-31 | 2001-08-03 | St Microelectronics Sa | ADAPTING THE TRANSMISSION POWER OF AN ELECTROMAGNETIC TRANSPONDER DRIVE |
EP1154368A1 (en) * | 2000-05-12 | 2001-11-14 | STMicroelectronics S.A. | Reader having means for determining the number of electromagnetic transponders in the field of the reader |
EP1154366A1 (en) | 2000-05-12 | 2001-11-14 | STMicroelectronics S.A. | Presence validation of an electromagnetic transponder in the field of a reader |
WO2002013124A1 (en) * | 2000-08-09 | 2002-02-14 | Stmicroelectronics S.A. | Detection of an electric signature of an electromagnetic transponder |
US6465903B1 (en) | 1998-06-22 | 2002-10-15 | Stmicroelectronics S.A. | Transmission of an operating order via an A.C. supply line |
US6473028B1 (en) | 1999-04-07 | 2002-10-29 | Stmicroelectronics S.A. | Detection of the distance between an electromagnetic transponder and a terminal |
US6476709B1 (en) | 1998-06-22 | 2002-11-05 | Stmicroelectronics S.A. | Transmission of digital data over an A.C. supply line |
US6547149B1 (en) | 1999-04-07 | 2003-04-15 | Stmicroelectronics S.A. | Electromagnetic transponder operating in very close coupling |
US6650229B1 (en) | 1999-04-07 | 2003-11-18 | Stmicroelectronics S.A. | Electromagnetic transponder read terminal operating in very close coupling |
US6650226B1 (en) | 1999-04-07 | 2003-11-18 | Stmicroelectronics S.A. | Detection, by an electromagnetic transponder reader, of the distance separating it from a transponder |
US6703921B1 (en) | 1999-04-07 | 2004-03-09 | Stmicroelectronics S.A. | Operation in very close coupling of an electromagnetic transponder system |
EP1420357A1 (en) * | 2002-11-12 | 2004-05-19 | Sharp Kabushiki Kaisha | Electromagnetic coupling characteristic adjustment method in non-contact power supply system, power supply device, and non-contact power supply system |
US6784785B1 (en) | 1999-04-07 | 2004-08-31 | Stmicroelectronics S.A. | Duplex transmission in an electromagnetic transponder system |
WO2006018229A1 (en) | 2004-08-16 | 2006-02-23 | Giesecke & Devrient Gmbh | Bidirectional wireless charging process for several batteries |
US7006041B2 (en) * | 2003-07-25 | 2006-02-28 | Ntt Docomo, Inc. | Radio receiver, radio transmitter and impedance control method |
US7107008B2 (en) | 2000-05-12 | 2006-09-12 | Stmicroelectronics S.A. | Validation of the presence of an electromagnetic transponder in the field of a phase demodulation reader |
WO2006097259A1 (en) * | 2005-03-14 | 2006-09-21 | Giesecke & Devrient Gmbh | Data transmission method and a frid reader provided with a coil and a control circuit for field quenching outside of a communication area |
WO2007046053A1 (en) | 2005-10-17 | 2007-04-26 | Nxp B.V. | Electronic circuit for a contactless reader device |
WO2008050085A1 (en) * | 2006-10-24 | 2008-05-02 | Innovision Research & Technology Plc | Near field rf communicators and near field rf communications enabled devices |
EP2254074A1 (en) | 2009-05-20 | 2010-11-24 | Legic Identsystems Ag | Read/write device for non-contact communication |
EP2263322A1 (en) * | 2008-04-03 | 2010-12-22 | Canon Kabushiki Kaisha | Communication terminal, computer-readable storage medium, and communication method |
US8130159B2 (en) | 2000-08-17 | 2012-03-06 | Stmicroelectronics S.A. | Electromagnetic field generation antenna for a transponder |
FR2978890A1 (en) * | 2011-08-05 | 2013-02-08 | Continental Automotive France | Method for calibrating electronic radio frequency identification reader in automobile, involves correcting transmission power of signal by proportionality coefficient when difference between control and measures values is changed |
US8594567B2 (en) | 2004-08-16 | 2013-11-26 | Giesecke & Devrient Gmbh | Controlled wireless charging of an accumulator in a chipcard |
GB2502848A (en) * | 2012-06-06 | 2013-12-11 | Samsung Electronics Co Ltd | Adaptive Antenna Impedance Matching |
GB2502787A (en) * | 2012-06-06 | 2013-12-11 | Samsung Electronics Co Ltd | Adaptive Antenna Impedance Matching |
WO2013185094A1 (en) * | 2012-06-08 | 2013-12-12 | Qualcomm Incorporated | Control of transmit power and adjustment of antenna tuning network of a wireless device |
US8836481B2 (en) | 2007-01-08 | 2014-09-16 | Quotainne Enterprises Llc | Transponders and methods for operating a transponder |
US9099878B2 (en) | 2011-03-23 | 2015-08-04 | Samsung Electro-Mechanics Co., Ltd. | Wireless power transmitter and wireless power transceiver |
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DE102004022839A1 (en) * | 2004-05-08 | 2005-12-01 | Conti Temic Microelectronic Gmbh | Transmitting circuit for a transponder system for transmitting a digital signal via a transmitting antenna |
WO2012166912A2 (en) | 2011-05-31 | 2012-12-06 | Plum Labs, Llc | Switchable antenna elements for a wireless communications device |
US9191829B2 (en) * | 2011-05-31 | 2015-11-17 | Facebook, Inc. | Sensing proximity utilizing a wireless radio subsystem |
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KR101382929B1 (en) * | 2011-12-19 | 2014-04-09 | 엘지이노텍 주식회사 | Apparatus for matching impedence and method for matching impedence |
KR101848303B1 (en) | 2012-07-10 | 2018-04-13 | 삼성전자주식회사 | Method for controlling power trasnmitting of wireless power transmitter and the wireless power transmitter thereof |
KR101428360B1 (en) * | 2013-01-24 | 2014-08-14 | 서울대학교산학협력단 | Method, system and computer-readable recording medium for wireless power transfer |
CN110208674B (en) * | 2019-05-08 | 2021-05-25 | 天津大学 | Directional coupling near-field probe and system for nonlinear radiation signal detection |
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- 1998-12-18 CA CA002287441A patent/CA2287441A1/en not_active Abandoned
- 1998-12-18 BR BR9808937-4A patent/BR9808937A/en not_active IP Right Cessation
- 1998-12-18 AU AU20040/99A patent/AU2004099A/en not_active Abandoned
- 1998-12-18 KR KR1019997009609A patent/KR20010006519A/en not_active Application Discontinuation
- 1998-12-18 EP EP98964796A patent/EP0976203A4/en not_active Withdrawn
- 1998-12-18 WO PCT/US1998/027003 patent/WO1999043096A1/en not_active Application Discontinuation
- 1998-12-18 TR TR1999/02594T patent/TR199902594T1/en unknown
- 1998-12-18 CN CN98804324A patent/CN1252908A/en active Pending
- 1998-12-18 JP JP54250099A patent/JP2001520855A/en active Pending
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Cited By (45)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6476709B1 (en) | 1998-06-22 | 2002-11-05 | Stmicroelectronics S.A. | Transmission of digital data over an A.C. supply line |
US6465903B1 (en) | 1998-06-22 | 2002-10-15 | Stmicroelectronics S.A. | Transmission of an operating order via an A.C. supply line |
US6473028B1 (en) | 1999-04-07 | 2002-10-29 | Stmicroelectronics S.A. | Detection of the distance between an electromagnetic transponder and a terminal |
US6784785B1 (en) | 1999-04-07 | 2004-08-31 | Stmicroelectronics S.A. | Duplex transmission in an electromagnetic transponder system |
US6703921B1 (en) | 1999-04-07 | 2004-03-09 | Stmicroelectronics S.A. | Operation in very close coupling of an electromagnetic transponder system |
US6650226B1 (en) | 1999-04-07 | 2003-11-18 | Stmicroelectronics S.A. | Detection, by an electromagnetic transponder reader, of the distance separating it from a transponder |
US6650229B1 (en) | 1999-04-07 | 2003-11-18 | Stmicroelectronics S.A. | Electromagnetic transponder read terminal operating in very close coupling |
US6547149B1 (en) | 1999-04-07 | 2003-04-15 | Stmicroelectronics S.A. | Electromagnetic transponder operating in very close coupling |
EP1134690A1 (en) * | 2000-01-31 | 2001-09-19 | STMicroelectronics S.A. | Transmission power adaptation in a reader for electromagnetic transponders |
FR2804557A1 (en) * | 2000-01-31 | 2001-08-03 | St Microelectronics Sa | ADAPTING THE TRANSMISSION POWER OF AN ELECTROMAGNETIC TRANSPONDER DRIVE |
JP2002033680A (en) * | 2000-05-12 | 2002-01-31 | Stmicroelectronics Sa | Confirmation of presence of electromagnetic transponder in field of read machine |
EP1154366A1 (en) | 2000-05-12 | 2001-11-14 | STMicroelectronics S.A. | Presence validation of an electromagnetic transponder in the field of a reader |
EP1154368A1 (en) * | 2000-05-12 | 2001-11-14 | STMicroelectronics S.A. | Reader having means for determining the number of electromagnetic transponders in the field of the reader |
JP4715025B2 (en) * | 2000-05-12 | 2011-07-06 | エステーミクロエレクトロニクス ソシエテ アノニム | Confirmation of the presence of electromagnetic transponders in the field of the reader |
FR2808946A1 (en) * | 2000-05-12 | 2001-11-16 | St Microelectronics Sa | VALIDATION OF THE PRESENCE OF AN ELECTROMAGNETIC TRANSPONDER IN THE FIELD OF A READER |
FR2808945A1 (en) * | 2000-05-12 | 2001-11-16 | St Microelectronics Sa | EVALUATION OF THE NUMBER OF ELECTROMAGNETIC TRANSPONDERS IN THE FIELD OF A READER |
US7107008B2 (en) | 2000-05-12 | 2006-09-12 | Stmicroelectronics S.A. | Validation of the presence of an electromagnetic transponder in the field of a phase demodulation reader |
FR2812986A1 (en) * | 2000-08-09 | 2002-02-15 | St Microelectronics Sa | DETECTION OF AN ELECTRIC SIGNATURE OF AN ELECTROMAGNETIC TRANSPONDER |
WO2002013124A1 (en) * | 2000-08-09 | 2002-02-14 | Stmicroelectronics S.A. | Detection of an electric signature of an electromagnetic transponder |
US8130159B2 (en) | 2000-08-17 | 2012-03-06 | Stmicroelectronics S.A. | Electromagnetic field generation antenna for a transponder |
US6889905B2 (en) | 2002-11-12 | 2005-05-10 | Sharp Kabushiki Kaisha | Electromagnetic coupling characteristic adjustment method in non-contact power supply system, power supply device, and non-contact power supply system |
EP1420357A1 (en) * | 2002-11-12 | 2004-05-19 | Sharp Kabushiki Kaisha | Electromagnetic coupling characteristic adjustment method in non-contact power supply system, power supply device, and non-contact power supply system |
US7006041B2 (en) * | 2003-07-25 | 2006-02-28 | Ntt Docomo, Inc. | Radio receiver, radio transmitter and impedance control method |
WO2006018229A1 (en) | 2004-08-16 | 2006-02-23 | Giesecke & Devrient Gmbh | Bidirectional wireless charging process for several batteries |
US8594567B2 (en) | 2004-08-16 | 2013-11-26 | Giesecke & Devrient Gmbh | Controlled wireless charging of an accumulator in a chipcard |
WO2006097259A1 (en) * | 2005-03-14 | 2006-09-21 | Giesecke & Devrient Gmbh | Data transmission method and a frid reader provided with a coil and a control circuit for field quenching outside of a communication area |
US7808389B2 (en) | 2005-03-14 | 2010-10-05 | Giesecke & Devrient Gmbh | Data transmission method and a RFID reader provided with a coil and a control circuit for field quenching outside of a communication area |
WO2007046053A1 (en) | 2005-10-17 | 2007-04-26 | Nxp B.V. | Electronic circuit for a contactless reader device |
US7926719B2 (en) | 2005-10-17 | 2011-04-19 | Nxp B.V. | Electronic circuit for a contactless reader device |
US9014623B2 (en) | 2006-10-24 | 2015-04-21 | Broadcom Europe Limited | Near field RF communicators and near field RF communications enabled devices |
WO2008050085A1 (en) * | 2006-10-24 | 2008-05-02 | Innovision Research & Technology Plc | Near field rf communicators and near field rf communications enabled devices |
US8140010B2 (en) | 2006-10-24 | 2012-03-20 | Innovision Research & Technology Plc | Near field RF communicators and near field RF communications enabled devices |
US8836481B2 (en) | 2007-01-08 | 2014-09-16 | Quotainne Enterprises Llc | Transponders and methods for operating a transponder |
EP2263322A4 (en) * | 2008-04-03 | 2012-01-11 | Canon Kk | Communication terminal, computer-readable storage medium, and communication method |
US8676395B2 (en) | 2008-04-03 | 2014-03-18 | Canon Kabushiki Kaisha | Communication terminal, computer-readable storage medium, and communication method |
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WO2013185094A1 (en) * | 2012-06-08 | 2013-12-12 | Qualcomm Incorporated | Control of transmit power and adjustment of antenna tuning network of a wireless device |
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Also Published As
Publication number | Publication date |
---|---|
CA2287441A1 (en) | 1999-08-26 |
AU2004099A (en) | 1999-09-06 |
JP2001520855A (en) | 2001-10-30 |
EP0976203A1 (en) | 2000-02-02 |
BR9808937A (en) | 2000-08-01 |
CN1252908A (en) | 2000-05-10 |
TR199902594T1 (en) | 2000-07-21 |
EP0976203A4 (en) | 2002-08-28 |
KR20010006519A (en) | 2001-01-26 |
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