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WO1999038108A1 - Configuration de haut-parleur comprenant un dispositif d'amortissement de l'augmentation de la pression acoustique accrue proche de la frequence resonante de base du haut-parleur - Google Patents

Configuration de haut-parleur comprenant un dispositif d'amortissement de l'augmentation de la pression acoustique accrue proche de la frequence resonante de base du haut-parleur Download PDF

Info

Publication number
WO1999038108A1
WO1999038108A1 PCT/GB1999/000242 GB9900242W WO9938108A1 WO 1999038108 A1 WO1999038108 A1 WO 1999038108A1 GB 9900242 W GB9900242 W GB 9900242W WO 9938108 A1 WO9938108 A1 WO 9938108A1
Authority
WO
WIPO (PCT)
Prior art keywords
controller
voltage supply
regulator
contactless token
token
Prior art date
Application number
PCT/GB1999/000242
Other languages
English (en)
Inventor
Neil Andrew Mcdonald
Melvin Paul Clarkson
Klaus Schroeder
Original Assignee
Marconi Communications Limited
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Marconi Communications Limited filed Critical Marconi Communications Limited
Priority to AU21793/99A priority Critical patent/AU2179399A/en
Publication of WO1999038108A1 publication Critical patent/WO1999038108A1/fr

Links

Classifications

    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; 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 OR CALCULATING; 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

Definitions

  • TRANSACTION SYSTEM This invention relates to a transaction system in which a portable token, for example a
  • the card is used in conjunction with a device, often termed a terminal, to perform a transaction of some kind.
  • a device often termed a terminal
  • the invention is particularly, but not exclusively, related to
  • Contactless tokens work on, or close to, a terminal which provides power. This power is supplied via a RF (radio frequency) induction field which is referred to as a carrier. Power is transferred from an aerial on the terminal to an aerial on the token and is akin to the terminal being a primary coil of a transformer and the token a secondary coil. In particular embodiments both the terminal and the token each have a single coil aerial.
  • RF radio frequency
  • data is transmitted from the terminal to the token and vice versa.
  • the exchange of data is used to perform a transaction. Transmission of data from the terminal is straightforward because it is simply modulated onto the carrier. Transmission of data from the token to the terminal may be effected by switching an impedance in the token to modulate the amplitude of the carrier at the terminal as the token draws extra power from the terminal due to the switching action.
  • a regulator such as a shunt regulator, is incorporated into circuitry connected to the token
  • the controller may try to take more current than is readily available. This can happen when the controller is switched on, if there is a change made to the clock speed (for example increased) at which the controller operates or if the controller is performing a particular function which requires a relatively high power, such as writing to EEPROM. If the controller tries to take more current than is available from the regulator the voltage supplied to the controller falls. If the voltage falls sufficiently then the controller may give unreliable operation. If the voltage falls by a larger amount then the unregulated voltage supplied to the token by the terminal may also fall. This could cause interface circuitry on the token, such as anti-collision circuitry, to stop working.
  • the normal method of measuring current in an integrated circuit is by measuring the voltage that it drops across a resistor through which it flows. Measured voltage is compared with a reference voltage supplied by a reference circuit such as a bandgap reference circuit. This is inaccurate due to variation in the absolute values of the resistor, the bandgap reference, the voltage reference and the comparator and which may vary due to manufacturing tolerances and
  • This resistor could be located between the regulator and the input to supply power to the controller. This would measure the current directly being used by the controller. However, this would waste power and cause the voltage supplied to the controller to vary with current drawn because as more current is drawn by the controller, more voltage would be dropped across the resistor and therefore less would be available to the controller. Also, to detect accurately a low current being used by the controller, for example when it has a low clock rate, requires a large resistor value which will cause greater power dissipation and drop significant voltage across itself.
  • the invention provides a method of controlling a power supply to a controller on a contactless token the token comprising an interface having a regulator for controlling a voltage supply to the controller characterised in that the regulator compares the voltage supply to a first reference voltage supply to produce a control voltage which is compared to a second reference voltage supply to detect when the controller is drawing too much current.
  • the invention provides a contactless token the token having an interface for providing power to a controller the interface having a regulator
  • the regulator uses a comparator to compare the voltage supply to a first reference voltage supply to produce a control voltage which is compared to a second reference voltage supply to
  • first and second reference voltages originate from the same source.
  • the invention provides a transaction system incorporating a contactless token operating a method according to the first aspect of the invention or incorporating a contactless token according to the second aspect of the invention.
  • the regulator Preferably the regulator generates a control signal when the voltage supply falls too far relative to the reference voltage supply.
  • the token detects when the voltage supply is at an end of its allowed range and then provides a control signal indicating that the controller is drawing too much current.
  • the signal indicating that the controller is drawing too much current is used to change operation of the controller so that it draws less current.
  • the comparator of the regulator provides an output to a switch which directs current flow to control the voltage supply.
  • the switch is a transistor such as
  • the switch may be used to measure the voltage supply.
  • the regulator is a shunt regulator.
  • the reference voltage supply is provided by the controller.
  • the controller is a microprocessor.
  • the token is a smart card.
  • Figure 1 shows a circuit on a contactless token for receiving electrical power and controlling power supply to a controller
  • Figure 2 shows a circuit for producing a reference voltage in controlling power supply to a controller.
  • FIG. 1 shows part of an interface circuit 10 for a contactless token.
  • the circuit 10 has an aerial 12 which receives electrical energy in the form of a carrier from a terminal (not shown).
  • the aerial is tuned with a capacitor 14 to receive a particular frequency of the carrier and to generate an alternating signal in the circuit 10.
  • the alternating signal is rectified by a rectifier 16 to provide the token with a DC power supply.
  • the output of the rectifier 16 has a ripple voltage and so a smoothing capacitor 18 is used to smooth the output of the rectifier 16 to provide a smoothed DC voltage V unreg .
  • the carrier providing a power supply for the token, it may be modulated with information in the form of transaction data, a clock signal (from which
  • the token can derive a clock for its controller) or both.
  • the information remains present
  • the information may be extracted at point 20.
  • the circuit 10 is provided with a shunt regulator 24.
  • the shunt regulator 24 regulates the flow of current through a transistor 26 from a relatively high potential rail 28 to a relatively low potential rail 30. This serves to maintain the steady voltage supply
  • V cc of rail 28 which is supplied to the controller 22.
  • the transistor 26 is a field effect transistor. Operation of the transistor 26 is controlled by an operational amplifier 32 which compares a proportion of voltage on rail 28 against a known reference voltage 34 to produce a controlling voltage 36. Resistors 38 and 40
  • divider chain which scales the voltage on rail 28 to a suitable value at point 50 which is comparable with reference voltage 34.
  • the controlling voltage 36 for the shunt regulator 24 is measured at the gate or base of transistor 26. If the controlling voltage 36 at the transistor 26 falls too far this implies that the transistor is not operating and is switched off. This means that no current is flowing from drain to source in the transistor 26 which means that the controller 22 is taking all the available current. To detect this condition the controlling voltage 36 is compared with a known reference voltage 42 in a detector 44 to generate a signal 46 when the controlling voltage 36 falls too far.
  • the reference voltage 42 could be the same as reference voltage 34 and both could be generated by a band gap circuit.
  • controlling voltage 36 which controls the operation of the transister
  • V cc the voltage supply V cc this indicates that the controller 22 is drawing too much power. If V cc is at a correct level, current flows in the shunt
  • V cc is not stable. Once this condition has been detected, appropriate action can be taken, for example resetting the controller 22 or slowing or stopping its clock using signal 46.
  • a method of controlling the clock speed on a token by using a variable tone modulated onto the carrier is described in GB patent application 9706019.
  • the token can re-start or be set to standard operating parameters after a period of time and the shunt regulator 24 can check if controller 22 is still drawing too much current. The problem would be alleviated if a user of the token placed it closer to a terminal so that more power is available.
  • the method is highly sensitive to detecting when the controller 22 is taking more current than it should.
  • Figure 2 shows part of a circuit 60 which is used to generate the reference voltage 42.
  • shunt regulator 24 controls the voltage on rail 28 by controlling the amount of current which flows through transistor 26 to rail 30. As explained in the foregoing the circuit of Figure 1 is configured to measure this current and to detect when it reached a minimum value, that is, a value at which it is considered that the shunt regulator 24 is not functioning properly. If the shunt regulator 24 is not
  • a current source 62 having a known value. This is set to be the same as the minimum current flowing through the transistor 26 or a predetermined proportion of it.
  • the current source 62 is connected to a transistor 64 which has its gate connected to its drain.
  • Detector 44 compares the voltages of transistor 26 and transistor 64. As transistors 26 and transistor 64 are both on the same silicon die and have both been made under the same process conditions, the circuit of Figure 2 provides a very accurate way of detecting non-functioning of the shunt regulator 24.
  • Reference voltage 42 is the gate-source voltage (since the gate is joined to the drain) which is required to allow the fixed current of the current source 62 to flow through the transistor 64. Therefore if the transistors 26 and 64 are identical, the detector 44 detects when current flowing through the transistor 26 falls below that produced by the current source 62. If the transistors 26 and 64 are designed to have a specified proportional
  • the detector detects current flows in the transistors in a corresponding proportional relationship.
  • the detector 44 could be a comparator.
  • a current mirror could be incorporated into the circuit 10. This requires another transistor to have the same gate/source voltage as the transistor 26 and be arranged to take an exact proportion of the current, for example 1%, flowing through the transistor 26 without
  • This proportional current can be measured by checking the voltage drop it causes across a resistor of a known value.
  • the load resistor 48 (having a value R 0An ) between the rectifier 16 and the regulator 24.
  • the load resistor 48 allows a pre-determined current to be made available to the controller 22 and the regulator 24. The maximum current available is
  • V cc is the regulated voltage.
  • V cc is set by a divider chain and the reference voltage 34 and is fixed.
  • V ⁇ g will change depending on how much power the token captures from RF field. This will depend for example on position and orientation of the token with respect to the terminal aerial. Therefore the maximum available current will vary but will typically decrease as the token is moved further from the terminal.
  • Transmission of data from the token to the terminal is effected by switching a load or impedance 52 in parallel with the load resistor 48

Landscapes

  • 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)
  • Power Sources (AREA)
  • Dc Digital Transmission (AREA)
  • Near-Field Transmission Systems (AREA)

Abstract

La présente invention concerne une configuration de haut-parleur (1) comprenant un haut-parleur électrodynamique (3), un boîtier (4), et un dispositif d'amortissement (30) servant à amortir l'augmentation de la pression acoustique provoquée par le boîtier (4), à la fréquence f2 résonante de base du haut parleur qui a été décalée par le boîtier (4). Le dispositif d'amortissement (30) est formé par au moins un conduit (31, 32) et fournit une friction acoustique, chaque conduit (31, 32) étant réalisé avec l'aide d'une partie (21) du boîtier (4) et d'une partie associée (33) de la configuration du haut-parleur (1), dont la partie associée (33) jouxte la partie (21) du boîtier (4).
PCT/GB1999/000242 1998-01-24 1999-01-22 Configuration de haut-parleur comprenant un dispositif d'amortissement de l'augmentation de la pression acoustique accrue proche de la frequence resonante de base du haut-parleur WO1999038108A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU21793/99A AU2179399A (en) 1998-01-24 1999-01-22 Transaction system

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9801442A GB2333493B (en) 1998-01-24 1998-01-24 Transaction system
GB9801442.6 1998-01-24

Publications (1)

Publication Number Publication Date
WO1999038108A1 true WO1999038108A1 (fr) 1999-07-29

Family

ID=10825760

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1999/000242 WO1999038108A1 (fr) 1998-01-24 1999-01-22 Configuration de haut-parleur comprenant un dispositif d'amortissement de l'augmentation de la pression acoustique accrue proche de la frequence resonante de base du haut-parleur

Country Status (3)

Country Link
AU (1) AU2179399A (fr)
GB (2) GB2333493B (fr)
WO (1) WO1999038108A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1089217A1 (fr) * 1999-10-01 2001-04-04 Fujitsu Limited Circuit intégré à semi-conducteurs pour carte à puce sans contact

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7511621B1 (en) 1995-08-31 2009-03-31 Intermec Ip Corp. High-performance mobile power antennas
US7427912B1 (en) 1998-01-08 2008-09-23 Intermec Ip Corp. Method and system for storage and recovery of vital information on radio frequency transponders
JP3487428B2 (ja) 2000-10-31 2004-01-19 松下電器産業株式会社 電源回路および非接触ｉｃカード
US6942155B1 (en) 2001-05-31 2005-09-13 Alien Technology Corporation Integrated circuits with persistent data storage
US7377445B1 (en) 2001-05-31 2008-05-27 Alien Technology Corporation Integrated circuits with persistent data storage
US6812841B2 (en) 2002-01-23 2004-11-02 Intermec Ip Corp. Passive RFID tag that retains state after temporary loss of power
WO2003091943A1 (fr) * 2002-04-24 2003-11-06 Marconi Intellectual Property (Us) Inc Dispositif et procede de recharge d'une source d'energie
DE10245747B4 (de) * 2002-10-01 2005-12-01 Infineon Technologies Ag Kontaktloser Datenträger
JP4455079B2 (ja) 2004-01-30 2010-04-21 富士通マイクロエレクトロニクス株式会社 電源回路

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0492569A2 (fr) * 1990-12-28 1992-07-01 On Track Innovations Ltd. Système et méthode pour la transmission de données sans contact
US5479172A (en) * 1994-02-10 1995-12-26 Racom Systems, Inc. Power supply and power enable circuit for an RF/ID transponder

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2607608B1 (fr) * 1986-11-27 1989-03-24 Jacques Lewiner Perfectionnements aux objets codes identifiables par proximite et aux dispositifs pour changer les codes de ces objets
WO1989007295A1 (fr) * 1988-02-04 1989-08-10 Magellan Corporation (Australia) Pty. Ltd. Regulateur a shunt
DE4227551A1 (de) * 1992-08-20 1994-02-24 Eurosil Electronic Gmbh Chip-Karte mit Feldstärkedetektor

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0492569A2 (fr) * 1990-12-28 1992-07-01 On Track Innovations Ltd. Système et méthode pour la transmission de données sans contact
US5479172A (en) * 1994-02-10 1995-12-26 Racom Systems, Inc. Power supply and power enable circuit for an RF/ID transponder

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1089217A1 (fr) * 1999-10-01 2001-04-04 Fujitsu Limited Circuit intégré à semi-conducteurs pour carte à puce sans contact
US6343022B1 (en) 1999-10-01 2002-01-29 Fujitsu Limited Semiconductor integrated circuit device for non-contact type IC card

Also Published As

Publication number Publication date
AU2179399A (en) 1999-08-09
GB2333493B (en) 2000-07-05
GB2333495A (en) 1999-07-28
GB9801442D0 (en) 1998-03-18
GB9803381D0 (en) 1998-04-15
GB2333495B (en) 2000-04-26
GB2333493A (en) 1999-07-28

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