GB2307379A - Transponder device with overvoltage protection - Google Patents
Transponder device with overvoltage protection Download PDFInfo
- Publication number
- GB2307379A GB2307379A GB9624042A GB9624042A GB2307379A GB 2307379 A GB2307379 A GB 2307379A GB 9624042 A GB9624042 A GB 9624042A GB 9624042 A GB9624042 A GB 9624042A GB 2307379 A GB2307379 A GB 2307379A
- Authority
- GB
- United Kingdom
- Prior art keywords
- information card
- voltage
- circuit
- contact type
- type information
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
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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
-
- 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
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- 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
- G06K19/0723—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 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
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- G—PHYSICS
- G07—CHECKING-DEVICES
- G07B—TICKET-ISSUING APPARATUS; FARE-REGISTERING APPARATUS; FRANKING APPARATUS
- G07B15/00—Arrangements or apparatus for collecting fares, tolls or entrance fees at one or more control points
- G07B15/02—Arrangements or apparatus for collecting fares, tolls or entrance fees at one or more control points taking into account a variable factor such as distance or time, e.g. for passenger transport, parking systems or car rental systems
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- Engineering & Computer Science (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Business, Economics & Management (AREA)
- Finance (AREA)
- Near-Field Transmission Systems (AREA)
- Channel Selection Circuits, Automatic Tuning Circuits (AREA)
Abstract
A transponder-based ticket 23, for automatic travel ticket 'clipping', includes control circuitry for preventing damage to its components when placed too near to a transmitting, interrogating/writing device (2, fig.5). Included in the control circuitry is a variable capacitor C23, which is fed a rectified version of the voltage appearing on loop antenna 10 via resistor R23. Capacitor C23 is normally set so that the resonant circuit is tuned to the transmitting frequency of the interrogator. However, if the voltage received is too large, the capacitance of C23 is adjusted, via the feedback signal from R23, so that the resonant circuit oscillates at a frequency offset from the interrogator's transmitting frequency, thus reducing the amplitude of the received signal. When transmitting data from the transponder, FET 24 switches resistance R24 in and out of the resonant circuit, thereby enabling two different resonant frequencies to be used for transmission.
Description
NON-CONTACT TYPE INFORMATION CARD
This invention relates to an information card used in a non-contact type card system such as an automatic ticket clipping system or the like.
In the automatic ticket clipping system utilised at present, there has been employed a method for reading out information from the ticket using a magnetic head which is contacted with the ticket on insertion thereof into an automatic ticket clipping machine by a user. Due to this fact, the is put to the trouble of having to bring out the commuter ticket from his or her case, bag or the like every time the user needs to use the ticket, and to insert it into the automatic ticket clipping machine.
In view of this fact, the applicants have already proposed a non-contact type card system which does not require such troublesome procedures and which is convenient in use.
According to this non-contact type card system, since information can be given or received in a non-contact manner (data communication or the like), it becomes possible that a user can pass through an automatic ticket clipping machine while in a state in which the commuter ticket is still stored in the case, etc., which improves convenience.
Figure 5 of the accompanying drawings illustrates such a non-contact type card system. In this case, the noncontact type card system is constructed by the reader/writer 2 corresponding to the aforesaid automatic ticket clipping machine and an information card 3 corresponding to the aforesaid commuter ticket, wherein electrical power is supplied via the medium of an applied electromagnetic wave and concurrently data is read or written.
Firstly, referring to Figure 6, an internal operation in the case where information is read out of the information card 3 by the reader/writer 2 will be described.
However, Figure 6 is a circuit diagram in which only a circuit concerning the reading-out of information of the information card 3 and a circuit concerning an overvoltage for restricting an overvoltage generated in the information card is extracted and shown.
At first, the reader/writer 2 at the reading-out side generates a desired carrier signal with a carrier generator 2A, the signal is amplified by a voltage control type amplifier 4, thereafter the signal is radiated as a magnetic field through a loop antenna 9.
At this time, when the information card 3 is placed within a range in which an electromagnetic induction signal may be sufficiently induced with the loop antenna 9, electrical power comes to be supplied from the reader/writer 2 to the information card 3. Then, it is naturally found that and electrical current flows in the loop antenna 9 and an output resistor R1 of the voltage control type amplifier 4, and so the carrier output level is decreased due to a voltage drop corresponding to the output resistor R1.
A degree of drop of this output level is changed in response to a resonance state of the resonance circuit formed by the loop antenna 9 and the capacitors C3, C4 at the information card 3.
Accordingly, when a FETli is turned on/off in response to the read-out information at the information card 3 so as to change the resonance state, a carrier level for driving the loop antenna 9 within the reader/writer 2 is changed in response to the read-out information of the information card 3.
When the variation in this carrier level is detected by an envelope detecting diode D1, is becomes possible to read out data.
In the case where the information card 3 gets very close to the loop antenna 9, quite large-sized carrier amplitudes may be produced at both ends of the loop antenna 9 which might damage its internal circuitry, so that there is provided an overvoltage protection circuit for protecting the inner circuit against such an overvoltage as above. The overvoltage protection circuit is configured such that when amplitude levels generated at both ends of the loop antenna 9 exceed the accumulated voltage of the groups 12A, 12B of diodes, a quite high current flows in the diode groups 12A and 12B to restrict an increase in voltage.
However, the non-contact type card system proposed in the early application had the following problems.
Firstly, in the reading-out process in the aforesaid non-contact type card system, there occurred a problem of "blind spots", i.e. areas where data cannot be read out irrespective of the fact that the information card 3 and the reader/writer 2 are placed at such a distance as one in which a relative induction may be produced from each other between the loop antenna 9 and 10.
The reason for this is shown in Figure 7. This diagram indicates how carrier amplitude levels generated at both ends of the loop antenna 9 on the side of reader/writer 2 are changed in the case where a capacitance of a parallel resonance circuit at the information card 3 (the loop antenna 10 and the capacitor C3) is changed for each of the distances between the information card 3 and the reader/writer 2, respectively. According to this diagram, it shows that no change occurs at the carrier amplitude levels appearing at both ends of the loop antenna 9 even if a resonance capacitance is changed at a middle distance region.
Accordingly, it is not possible to read out data from the information card 3 at the middle distance region.
A second problem is that the occurrence of these blind spots of data reading-out are quite sensitive to the displacement of tuning frequency of a parallel resonance circuit (the loop antenna 10 and the capacitor C3) arranged on the information card 3 and in the case where a tuning displacement occurs; the position and range of the data reading-out blind spot are remarkably disturbed, so that this system is not suitable for a mass production.
In addition, a third problem consists in the fact that both a positive overvoltage protection and a longdistance data receiving operation are quite difficult to attain in the case of the overvoltage protection circuit system applied in the aforesaid non-contact type card system 1. That is, it was difficult to accommodate for such a system capable of performing a wide range communication ranging from a close-contact position to a quite far away position.
The reason for this is as follows. In the case where a communication can be performed up to quite a way away, it is necessary to radiate a quite strong magnetic field from the reader/writer 2. However, when the position is near the card, the electrical power received by the information card 3 then becomes quite high in response to it, resulting in that the overvoltage protection part must be enforced. In practice, if a value of the resistor element R2 is reduced and a current flowing into the overvoltage protection circuit is made quite high, and thereby the overvoltage is restricted; the reduction in the value at the resistor element R2 may also lead to a remarkable restriction of amplitude variation of voltage received at the loop antenna 10.However, this data transfer system is carried out under an amplitude modulation, so it is natural that a loss of the amplitude modulation does not enable the received data to be demodulated.
The present invention has been devised in view of the foregoing, and provides an information card in which data can be communicated in an interactive mode while the information card is being positively protected against the overvoltage in all the regions ranging from the reading-out device from the far distance where an electrical power can be slightly supplied to the information card from the readingout device to a quite near distance.
According to the present invention there is provided a non-contact type information card comprising:
means for generating a voltage in response to a variation in a magnetic field;
a resonator circuit for passing a component of said voltage in a specified frequency band;
means for rectifying an output of said resonator circuit; and
a protection circuit for applying an output voltage to said rectifier means and restricting a voltage generated by controlling said resonance circuit so as to change a resonance frequency thereof in the case where said output voltage becomes excessively large.
Since the resonance frequency of the resonance circuit is controlled in response to a receiving state of an electromagnetic wave from the reading-out device received by the resonance circuit, if the receiving state is too excessive, the resonance frequency is displaced to cause a receiving sensitivity of the device to be reduced. With such an arrangement as above, it is possible to provide a noncontact type information card in which an excessive voltage is prevented from being produced at the output of the resonance circuit and if the voltage is within a range to produce an electromagnetic induction with the reading-out device, an overvoltage application can be avoided with no sacrifice in a writing characteristic.
In addition the load state of the resonance circuit is electrically controlled by a control means arranged between an output of a rectifier means and the ground in response to the reading-out data, and thereby it is possible to provide a non-contact type information card in which information can be read out without being dependent on a positional relation if it is within a range to produce an electromagnetic induction with the reading-out device.
The invention will be further described by way of non-limitative example with reference to the accompanying drawings, in which:
Figure 1 is a connecting diagram showing an example of the configuration of the information card of the present invention;
Figure 2 is a graph showing a relationship between a load resistance and a drive voltage in a loop antenna at the reader/writer in a resonance circuit of a non-contact type information card;
Figure 3 is a circuit diagram showing an example of application in the case where the rectifier circuits of various circuit configurations are combined with the information card of the present invention;
Figure 4 is a connecting diagram showing an example of the configuration of the information card of the present invention;
Figure 5 is a block diagram showing a general configuration of the non-contact type card system;;
Figure 6 is a schematic connecting diagram showing only a circuit part related to the reading-out information stored in the information card and a circuit part related to an overvoltage protection for restricting an overvoltage generated in the information card in the non-contact type card system; and
Figure 7 is a graph showing a relation between a capacitance of a resonator capacitor in a resonator circuit and a drive voltage at a loop antenna of the reader /writer side of the non-contact type card system.
In the drawings,
1 is a non-contact type card system
2 is a card reader/writer
3,23,33 are information cards
8 is a printed circuit board
9,10 are loop antennae.
(1) First Preferred Embodiment
In Figure 1 in which the corresponding parts in
Figure 5 are denoted by the same reference numerals is shown an example of circuit configuration of the front end part of the information card 23 of the present invention.
In the case of the information card 23 shown in
Figure 1, it differs from that of Figure 5 in that the parallel resonance circuit is constituted by a loop antenna 10, capacitors C3, C4 and a variable capacitor C23. In addition, one end of the parallel resonance circuit is connected to the ground and the other end is connected to an anode of the diode D2.
A pure resistor element R23 is connected between a cathode side of the diode D2 and the variable voltage capacitor element C23 and a voltage rectified by the diode
D2 is applied to the variable capacitance element C23 as a control voltage.
In addition, the cathode side of the diode D2 is set such that the pure resistor element R24 is connected to the ground through a drain/source of a FET24 and this FET24 is on/off controlled in response to the read-out data to enable a load resistance value of the parallel resonance circuit to be variable and then a resonance frequency is changed.
With such a foregoing arrangement described above, a method for reading out information of the information card 23 with the reader/writer 2 (that is, a reading method) and an overvoltage protection method for restricting an overvoltage generated in the information card 23 when the information card 23 approaches very near the reader/writer 2 will be described.
At first, an operating principle of the information card 23 having the above construction will be described in reference to the case in which information is read out from the reader/writer 2.
The reader/writer 2 amplifies a desired frequency carrier generated at the carrier generator 2A to a desired level by a voltage-controlled type amplifier 4 and radiates it as a magnetic field through the loop antenna 9. In this case, when the information card 23 is sufficiently positioned in a range to induce an electromagnetic induction with the loop antenna 9, electrical power
is supplied from the reader/writer 2 to the information card 23.
Then, naturally, a current flows in the loop antenna 9 and the output resistor R1 of the voltage-controlled type amplifier 4 and a carrier output level is decreased due to a voltage drop corresponding to an output resistor R1. A degree of drop in the output level is determined by a value of load resistance between the cathode of the diode D2 at the information card 23 and the ground. Accordingly, if the value of the load resistance between the cathode of the diode D2 and the ground is changed by turning on/off the
FET24 in reference to the read-out information of the information card 23, a carrier level for driving the loop antenna 9 in the reader/writer 2 is changed in reference to the read-out information of the information card 23.The data reading-out operation is carried out by detecting this carrier level variation with the diode D1 for detecting an envelope.
However, in the case where the value of the load resistance is changed, it becomes apparent that a variation in the carrier amplitude of the reader/writer 2 does not depend upon a resonance state of the loop antenna 10 and the capacitor C3 as shown in Fig. 2. Accordingly, as long as the information card 23 is placed in a distance range where an electromagnetic induction is produced with the loop antenna 9 at the side of the reader/writer 2, it becomes possible to read out data in all regions.
During mass production, less influence is applied to the reading-out characteristic even if a tuning frequency is slightly displaced and further a dispersion in mass production is also restricted. In addition, the information reading-out system for the information card 23 provided in the present invention shows quite good adaptation for any type of rectifying circuit and thus it can be operated under any type of restricting conditions produced when the card is formed in IC.
Fig. 3 shows an example of application of various types of the rectifier/detector circuit.
Next, the operating principle of the overvoltage protection circuit of the information card 23 will be described. The operating principle of the present system consists in the fact that in the case where the information card 23 approaches quite near the loop antenna 9 of the reader/writer 2, a resonance frequency is displaced in response to a receiving level at the information card 23 to reduce a receiving efficiency and then an overvoltage is protected. The present information card 23 is operated such that a voltage rectified after receiving through the pure resistor element R23 is applied to the variable capacitor element C23 and then the capacitance is changed in response to the receiving level.
With such an operation as above, it becomes possible that the frequency is displaced and the receiving efficiency is reduced.
Practical operation is performed as follows. In the case where the information card 23 approaches quite near the loop antenna 9 of the reader/writer 2, it is natural that an electrical power energy received at the loop antenna 10 in the information card 23 is also increased. This received voltage is applied to the variable capacitance element C23 through the pure resistor element R23, so that resonance is displaced under the received voltage.
The fact that the displacement of the resonance frequency naturally results in a reduction of receiving efficiency.
Accordingly, a voltage received at the loop antenna 10 in the information card 23 is restricted and an overvoltage protection is accomplished. According to this overvoltage protection method, since the amplitude variation component received at the loop antenna 10 is not restricted, information of read-out data modulated in amplitude is not lost at the information card 23 and then a positive overvoltage protection becomes possible.
Naturally, the present system can be used together with another overvoltage protection circuit.
According to the aforesaid configuration, it is possible to provide a non-contact type information card in which as a capacitance element constituting the parallel resonance circuit, the variable capacitance element C23 having its capacitance variable in response to an applied voltage is used and a voltage after rectifying upon receiving is applied to the variable capacitance element
C23, and thereby even though the received voltage becomes excessive, a capacitance of the variable capacitance element C23 is changed in reference to the voltage to reduce a receiving efficiency and the received voltage does become excessive.Accordingly, it is possible to obtain the information card capable of reading out or writing data stably within any regions while the overvoltage protection is being carried out in a range where it can induce an electromagnetic induction between the reader/writer 2 and the same.
(2) Second Preferred Embodiment
In Fig. 4 in which the same reference numbers are applied to the corresponding parts in Fig. 1 is illustrated a second preferred embodiment of the information card of the present invention.
A difference between this information card 33 and the information card 23 illustrated in the first preferred embodiment consists in the fact that the connecting method for the rectifier circuit and the variable capacitance element is different and other portions have quite the same configuration as that of the information card 23.
In this case, when a connecting path of the variable capacitance element is applied in an AC manner, the smoothing capacitor C5 is sufficiently high and a connecting point between the loop antenna 10 and the resistor element R33 is kept at a ground level, so that it is equivalent to the case in which it is connected in parallel with the capacitor C4, the variable capacitance element C23 and the capacitor C3. Accordingly, the information card 33 operates in a quite same manner as that of the information card 23 shown in the first preferred embodiment. Accordingly, also in this case, it is possible to change the resonance frequency in response to a variation in capacitance of the variable capacitance element.
In addition, since a ground-connected diode is used as a rectifier/detector diode in this preferred embodiment, this card is quite preferable for an IC formation receiving various restrictions in circuit.
According to the aforesaid configuration, it is possible to obtain a non-contact type information card in which the variable capacitance element C23 of which capacitance is changed in response to an applied voltage is used as a capacitor element constituting a parallel resonance circuit, and a voltage after rectifying upon receiving is applied to the variable capacitance element
C23, so that even if the received voltage becomes excessive, the capacitance of the variable capacitance element C23 is changed in response to the voltage and a receiving efficiency is decreased and the received voltage can be prevented from becoming excessive amount.
Accordingly, it is possible to obtain an information card in which data can be read out or written stably in any regions while an overvoltage protection is being positively carried out within a range in which the information card generates an electromagnetic induction between the reader/ writer 2 and the same.
(3) Other Preferred Embodiments
In the aforesaid preferred embodiments, the example of the information card which is constructed as shown in
Figs. 1, 3 and 4 has been described. The present invention is not limited to this example and can be applied to another example of connection other than the above.
Although the case in which the resonance frequency is controlled by changing a capacitance of the variable capacitance element has been described, it can be controlled with other means.
As described above, according to the present invention, a resonance frequency of the resonance circuit passing a voltage component in a desired frequency band of voltages generated in response to a variation in a magnetic field is controlled in reference to an output voltage of a rectifier means for rectifying an output of the resonance circuit. Accordingly, even in the case where a large voltage is generated in the information card due to the fact a receiving state of an electromagnetic wave from a reading-out device side received by the resonance circuit is excessive, resulting in that the resonance frequency can be displaced with the voltage and the receiving sensitivity can be reduced. Accordingly, it is possible to provide a non-contact type information card capable of preventing an overvoltage from being applied with no sacrifice in the writing characteristic in a range in which the information card generates an electromagnetic induction between the reading-out device and the same.
In addition, it is possible to provide a noncontact type information card in which a loaded state of a resonator circuit is controlled electrically in response to the read-out data by the control means arranged between the output of the rectifier means and the ground, and thereby information can be positively read out without being dependent upon a positional relation in a range in which the information card generates an electromagnetic induction between the reading-out device and the same.
Claims (5)
1. A non-contact type information card comprising:
means for generating a voltage in response to a variation in a magnetic field;
a resonator circuit for passing a component of said voltage in a specified frequency band;
means for rectifying an output of said resonator circuit; and
a protection circuit for applying an output voltage to said rectifier means and restricting a voltage generated by controlling said resonance circuit so as to change a resonance frequency thereof in the case where said output voltage becomes excessively large.
2. A non-contact type information card according to claim 1, wherein said resonance circuit is composed of a parallel connection of a coil, a first capacitor and a voltage-controlled type variable capacitance capacitor; and
said protection circuit is operative to apply an output voltage of said rectifier means to said variable capacitance capacitor and variably controls a resonance frequency of said resonance circuit by varying its capacitance in response to said output voltage.
3. A non-contact type information card according to claim 1 or 2, wherein control means capable of controlling electrically a state of resistive load in said resonance circuit in response to the read-out data is arranged between an output of said rectifier means and the ground.
4. A non-contact type information card according to claim 3, wherein said control means is composed of a resistive element and a transistor element and electrically controls a loaded state by turning on or off said transistor element.
5. A non-contact type information card constructed and arranged to operate substantially as hereinbefore described with reference to and as illustrated in Figures 1 to 4 of the accompanying drawings
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32517095A JP3761001B2 (en) | 1995-11-20 | 1995-11-20 | Contactless information card and IC |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9624042D0 GB9624042D0 (en) | 1997-01-08 |
| GB2307379A true GB2307379A (en) | 1997-05-21 |
| GB2307379B GB2307379B (en) | 1999-09-29 |
Family
ID=18173800
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9624042A Expired - Fee Related GB2307379B (en) | 1995-11-20 | 1996-11-19 | Non-contact type information card |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JP3761001B2 (en) |
| GB (1) | GB2307379B (en) |
| HK (1) | HK1013485A1 (en) |
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| WO1998034319A1 (en) * | 1997-02-03 | 1998-08-06 | Sony Corporation | Equipment and method for transmitting electric power |
| EP0910034A2 (en) * | 1997-10-14 | 1999-04-21 | TEMIC Semiconductor GmbH | Modulation method for the data transmission from a transponder to a writer/reader |
| WO1999038109A1 (en) * | 1998-01-24 | 1999-07-29 | Marconi Communications Limited | Transaction system |
| EP0943171A1 (en) * | 1997-10-06 | 1999-09-22 | Atmel Corporation | Modulation compensated clamp circuit |
| WO2001035463A2 (en) * | 1999-10-20 | 2001-05-17 | Infineon Technologies Ag | Overvoltage protection arrangement |
| EP1509986A2 (en) * | 2002-03-13 | 2005-03-02 | Celis Semiconductor Corporation | Rectifier utilizing a grounded antenna |
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| JP4197417B2 (en) * | 2002-09-11 | 2008-12-17 | パナソニック株式会社 | Semiconductor integrated circuit and non-contact information medium |
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| US20050288739A1 (en) * | 2004-06-24 | 2005-12-29 | Ethicon, Inc. | Medical implant having closed loop transcutaneous energy transfer (TET) power transfer regulation circuitry |
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| JP2008067488A (en) * | 2006-09-07 | 2008-03-21 | Ricoh Co Ltd | Rectifying circuit |
| CN103633745B (en) * | 2007-03-27 | 2015-09-09 | 麻省理工学院 | For the method for wireless energy transfer |
| US8878393B2 (en) | 2008-05-13 | 2014-11-04 | Qualcomm Incorporated | Wireless power transfer for vehicles |
| KR101595755B1 (en) * | 2008-10-03 | 2016-02-19 | 가부시키가이샤 한도오따이 에네루기 켄큐쇼 | Semiconductor device |
| US9312924B2 (en) | 2009-02-10 | 2016-04-12 | Qualcomm Incorporated | Systems and methods relating to multi-dimensional wireless charging |
| US20100201312A1 (en) | 2009-02-10 | 2010-08-12 | Qualcomm Incorporated | Wireless power transfer for portable enclosures |
| US8854224B2 (en) | 2009-02-10 | 2014-10-07 | Qualcomm Incorporated | Conveying device information relating to wireless charging |
| JP5554937B2 (en) * | 2009-04-22 | 2014-07-23 | パナソニック株式会社 | Contactless power supply system |
| JP5515701B2 (en) * | 2009-12-04 | 2014-06-11 | ソニー株式会社 | Power transmission device, power reception device, and power transmission control method |
| JP5476194B2 (en) * | 2010-04-08 | 2014-04-23 | Ｎｅｃトーキン株式会社 | Non-contact power transmission and communication system, power transmission device and power reception device |
| JP6890379B2 (en) * | 2016-02-17 | 2021-06-18 | 株式会社Ｆｕｊｉ | Non-contact power supply device |
| JP6739190B2 (en) | 2016-03-01 | 2020-08-12 | ローム株式会社 | Contactless communication medium and electronic device using the same |
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| WO1998034319A1 (en) * | 1997-02-03 | 1998-08-06 | Sony Corporation | Equipment and method for transmitting electric power |
| EP0943171A1 (en) * | 1997-10-06 | 1999-09-22 | Atmel Corporation | Modulation compensated clamp circuit |
| EP0943171A4 (en) * | 1997-10-06 | 2003-05-07 | Atmel Corp | Modulation compensated clamp circuit |
| EP0910034A2 (en) * | 1997-10-14 | 1999-04-21 | TEMIC Semiconductor GmbH | Modulation method for the data transmission from a transponder to a writer/reader |
| EP0910034A3 (en) * | 1997-10-14 | 2002-12-11 | ATMEL Germany GmbH | Modulation method for the data transmission from a transponder to a writer/reader |
| WO1999038109A1 (en) * | 1998-01-24 | 1999-07-29 | Marconi Communications Limited | Transaction system |
| WO2001035463A2 (en) * | 1999-10-20 | 2001-05-17 | Infineon Technologies Ag | Overvoltage protection arrangement |
| WO2001035463A3 (en) * | 1999-10-20 | 2002-04-04 | Infineon Technologies Ag | Overvoltage protection arrangement |
| EP1509986A2 (en) * | 2002-03-13 | 2005-03-02 | Celis Semiconductor Corporation | Rectifier utilizing a grounded antenna |
| EP1509986A4 (en) * | 2002-03-13 | 2006-02-15 | Celis Semiconductor Corp | Rectifier utilizing a grounded antenna |
| CN100359782C (en) * | 2002-03-13 | 2008-01-02 | 塞利斯半导体公司 | Rectifier utilizing a grounded antenna |
| WO2005104022A1 (en) * | 2004-04-08 | 2005-11-03 | 3M Innovative Properties Company | Variable frequency radio frequency identification (rfid) tags |
| US7132946B2 (en) | 2004-04-08 | 2006-11-07 | 3M Innovative Properties Company | Variable frequency radio frequency identification (RFID) tags |
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| US8240577B2 (en) | 2005-05-30 | 2012-08-14 | Semiconductor Energy Laboratory Co., Ltd. | Semiconductor device |
| US9831722B2 (en) | 2005-07-12 | 2017-11-28 | Massachusetts Institute Of Technology | Wireless non-radiative energy transfer |
| US11685270B2 (en) | 2005-07-12 | 2023-06-27 | Mit | Wireless energy transfer |
| US11685271B2 (en) | 2005-07-12 | 2023-06-27 | Massachusetts Institute Of Technology | Wireless non-radiative energy transfer |
| US10666091B2 (en) | 2005-07-12 | 2020-05-26 | Massachusetts Institute Of Technology | Wireless non-radiative energy transfer |
| US10141790B2 (en) | 2005-07-12 | 2018-11-27 | Massachusetts Institute Of Technology | Wireless non-radiative energy transfer |
| US10097044B2 (en) | 2005-07-12 | 2018-10-09 | Massachusetts Institute Of Technology | Wireless energy transfer |
| EP1909384A3 (en) * | 2006-10-06 | 2015-11-25 | Semiconductor Energy Laboratory Co., Ltd. | Rectifier circuit with variable capacitor, semiconductor device using the circuit, and driving method therefor |
| WO2009140223A1 (en) * | 2008-05-13 | 2009-11-19 | Qualcomm Incorporated | Reverse link signaling via receive antenna impedance modulation |
| US9954399B2 (en) | 2008-05-13 | 2018-04-24 | Qualcomm Incorporated | Reverse link signaling via receive antenna impedance modulation |
| WO2010047850A1 (en) * | 2008-05-13 | 2010-04-29 | Qualcomm Incorporated | Receive antenna for wireless power transfer |
| WO2009140218A1 (en) * | 2008-05-13 | 2009-11-19 | Qualcomm Incorporated | Method and apparatus with negative resistance in wireless power transfers |
| CN102027688A (en) * | 2008-05-13 | 2011-04-20 | 高通股份有限公司 | Receive antenna for wireless power transfer |
| US9991747B2 (en) | 2008-05-13 | 2018-06-05 | Qualcomm Incorporated | Signaling charging in wireless power environment |
| US9831682B2 (en) | 2008-10-01 | 2017-11-28 | Massachusetts Institute Of Technology | Efficient near-field wireless energy transfer using adiabatic system variations |
| US8427386B2 (en) | 2008-10-30 | 2013-04-23 | Ids Microchip Ag | Method and circuit for transmitting and receiving radio waves with a single oscillatory circuit antenna |
| WO2010050906A1 (en) * | 2008-10-30 | 2010-05-06 | Vinko Kunc | Method and circuit for transmitting and receiving radio waves with a single oscillatory circuit antenna |
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| WO2016048844A1 (en) * | 2014-09-22 | 2016-03-31 | Cambridge Silicon Radio Limited | Receiver circuit |
| CN107209868B (en) * | 2014-09-22 | 2020-03-17 | 高通国际科技有限公司 | Receiver circuit |
| DE102015107886B4 (en) * | 2014-09-22 | 2020-10-22 | Qualcomm Technologies International, Ltd. | Receiver circuit |
| CN107209868A (en) * | 2014-09-22 | 2017-09-26 | 高通国际科技有限公司 | Acceptor circuit |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9624042D0 (en) | 1997-01-08 |
| JP3761001B2 (en) | 2006-03-29 |
| JPH09147070A (en) | 1997-06-06 |
| HK1013485A1 (en) | 1999-08-27 |
| GB2307379B (en) | 1999-09-29 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |