JP2012138007A - Non-contact type portable electronic device and non-contact type ic card - Google Patents

Non-contact type portable electronic device and non-contact type ic card Download PDF

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Publication number
JP2012138007A
JP2012138007A JP2010290993A JP2010290993A JP2012138007A JP 2012138007 A JP2012138007 A JP 2012138007A JP 2010290993 A JP2010290993 A JP 2010290993A JP 2010290993 A JP2010290993 A JP 2010290993A JP 2012138007 A JP2012138007 A JP 2012138007A
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circuit
non
ic card
switch
load
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JP2010290993A
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Japanese (ja)
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Tetsuji Miyata
哲次 宮田
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Toshiba Corp
株式会社東芝
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Abstract

[PROBLEMS] To avoid a state in which an external device cannot reproduce received data due to insufficient load modulation level, and can greatly improve the communication characteristics with the external device. An electronic device and a contactless IC card are provided.
In a contactless IC card that performs data communication without contact with an external device, a voltage after rectifying a received carrier wave is detected, and when the detected voltage value is equal to or less than a predetermined value, a load modulation circuit By connecting a second load element connected in parallel to the first load element, the load impedance value is lowered and the level of load modulation is increased.
[Selection] Figure 1

Description

  Embodiments described herein relate generally to a contactless portable electronic device such as a contactless IC card that performs data communication with an external device (a contactless card reader / writer) and a contactless IC card.

  In general, this type of non-contact type IC card receives an electromagnetic wave transmitted from a non-contact type card reader / writer, generates an operating voltage from the received electromagnetic wave, and operates. By performing wireless communication between them, information processing such as writing or reading of data with respect to a rewritable nonvolatile memory is performed.

  Such communication between the non-contact type IC card and the non-contact type card reader / writer is performed when the data is transmitted from the non-contact type card reader / writer to the non-contact type IC card. Transmits the data to the non-contact type IC card by subjecting the generated electromagnetic wave to ASK modulation. When a non-contact IC card transmits data to a non-contact card reader / writer, the non-contact IC card transmits data to the non-contact card reader / writer by applying load modulation to the received electromagnetic field. To do.

  The load modulation is generally performed by changing the impedance of a resistive load provided in a load modulation circuit in a non-contact type IC card by opening / closing operation of a switch element. When load modulation is applied, a change appears in the electromagnetic field due to the influence of the reflected wave. Therefore, the non-contact type card reader / writer detects the change in the electromagnetic field as a change in voltage or phase. Can receive the transmitted signal. Such a communication standard is defined by an international standard such as ISO / IEC14443.

  By the way, such a non-contact type IC card has recently been equipped with a load modulation circuit capable of setting communication conditions so that a communication hole is not possible even for non-contact type card readers / writers having various antenna impedances. Have been developed. This non-contact type IC card includes a first load modulation means based on real impedance and a second load modulation means based on imaginary impedance between one of a pair of antenna terminals and a ground potential node in a load modulation circuit. It is configured to be connected in parallel.

JP 2009-302615 A

  Conventionally, before performing data communication with a non-contact type card reader / writer, the load modulation method and load modulation intensity of the non-contact type IC card can be set. It is necessary to make settings in advance according to the writer, and it is necessary to optimize the settings each time communication is performed with a plurality of contactless card readers / writers. In addition, during data communication with the non-contact card reader / writer, the setting cannot be changed, so that a communication failure may occur.

  Therefore, the present invention can change the load modulation intensity during data communication with an external device, thereby avoiding a state where the external device cannot reproduce received data due to insufficient load modulation level. It is an object of the present invention to provide a non-contact portable electronic device and a non-contact IC card that can significantly improve communication characteristics with an external device.

  A non-contact portable electronic device according to an embodiment includes an antenna coil and a tuning capacitor for performing wireless communication with an external device in the non-contact portable electronic device that performs data communication without contact with the external device. A resonance circuit comprising: a rectifying circuit connected to the resonance circuit and rectifying an electromagnetic wave transmitted from the external device received by the resonance circuit; and an operating voltage of the portable electronic device from an output of the rectification circuit Power generation means for generating the output voltage, voltage detection means for detecting the output voltage of the rectifier circuit, a receiver circuit for reproducing the received data based on the output of the rectifier circuit, and a predetermined value based on the received data obtained from the receiver circuit Information processing means for performing information processing, transmission data generation, and the like, and a first load connected between one of the output terminals of the rectifier circuit and the ground potential A first switch element connected in series to the first load element, a transmission circuit that controls opening and closing of the first switch element in accordance with transmission data from the information processing means, and the first A second load element connected in parallel to the load element, a second switch element connected in series to the second load element, and the second switch element detected by the voltage detecting means Switch control means for controlling opening and closing according to the voltage value.

1 is a block diagram schematically showing a configuration of a non-contact IC card as a non-contact portable electronic device according to an embodiment. The top view which shows typically the external appearance structure of an IC card. The graph which shows the relationship of the detection voltage value of the voltage detection circuit with respect to the distance of a non-contact-type IC card and a non-contact-type IC card reader / writer. The block diagram of the load modulation circuit 27 at the time of using the 2nd resistive element 35 and the 2nd switch element 36 in multiple numbers, respectively. The flowchart explaining the operation | movement in the case of FIG.

Hereinafter, embodiments will be described with reference to the drawings.
FIG. 1 schematically shows a configuration of a non-contact IC card as a non-contact portable electronic device according to the present embodiment. The non-contact type IC card 11 includes a resonance circuit 13 for wireless transmission / reception with a non-contact type IC card reader / writer 12 as an external device, and an IC chip 14 connected to the resonance circuit 13. These are integrated into an IC module 15, which is housed (embedded) in the IC card body 16 as shown in FIG.

  The resonance circuit 13 includes an antenna coil 17 and a tuning capacitor 18 that forms an LC parallel resonance circuit with the antenna coil 17 and receives an electromagnetic wave from the non-contact type IC card reader / writer 12.

  The IC chip 14 is connected to the output terminal of the full-wave rectifier circuit 21 that rectifies the electromagnetic wave (carrier wave) received by the resonance circuit 13 and converts it into a DC voltage, and a smoothing circuit (smooth circuit that smoothes the rectified voltage). For example, a capacitor 23, a regulator 23 serving as a power source generating means for generating a stabilized DC voltage from the DC voltage smoothed by the smoothing circuit 22 and supplying it to each unit as an operating voltage, and a voltage smoothed by the smoothing circuit 22 A voltage detection circuit 24 serving as a voltage detection means to detect, a reception circuit 25 connected to the output terminal of the rectifier circuit 21 to reproduce (demodulate) received data, and a switch element of a load modulation circuit 27 to be described later according to transmission data. The transmission circuit 26 that controls opening and closing, the load modulation circuit 27 connected to the output terminal of the rectifier circuit 21, and the load change according to the voltage value detected by the voltage detection circuit 24. Switch switching control circuit 28 as switch control means for controlling opening and closing of the switch elements of the circuit 27, a control unit (for example, CPU) 29 as information processing means for performing various information processing and overall control, and a control program for the control unit 29 ROM (Read Only Memory) 30 in which data are stored in advance, RAM (Random Access Memory) 31 in which temporary data is written and read, and EEPROM (Electrical Power) in which various data are stored A non-volatile memory 32 such as an erasable and programmable read-only memory.

  For example, the receiving circuit 25 reproduces the received data by detecting the envelope of the ASK-modulated signal on the carrier wave based on the output of the rectifier circuit 21 and binarizing it with a comparator.

  The transmission circuit 26 changes the value of the load resistance by turning on and off the first switch element 34 of the load modulation circuit 27 in correspondence with “1” and “0” of the transmission data sent from the control unit 29. Data is transmitted to the non-contact type IC card reader / writer 12 by the load modulation method.

  The load modulation circuit 27 includes a first resistance element 33 as a first load element connected in series between one output terminal (positive electrode side) of the rectifier circuit 21 and the other output terminal (ground potential), and a first resistance element 33. One switch element (for example, FET transistor) 34, a second resistor element 35 as a second load element connected in series between both ends of the first resistor element 33, and a second switch element (for example, an FET transistor) 36).

  The switch switching control circuit 28 switches the load modulation level (load modulation intensity) by turning on and off the second switch element 36 of the load modulation circuit 27 in accordance with the voltage value detected by the voltage detection circuit 24.

  The control unit 29 performs predetermined information processing based on the reception data obtained from the reception circuit 25, for example, writes and reads data to and from the RAM 31 and the nonvolatile memory 32, and generates transmission data to the transmission circuit 26 and the like. . The overall control of the IC chip 14 is also performed.

  FIG. 3 is a graph showing the relationship of the detected voltage value V (volts) of the voltage detection circuit 24 with respect to the distance d (mm) between the non-contact type IC card 11 and the non-contact type IC card reader / writer 12. The operation of the main part will be described with reference to FIG.

  The example of FIG. 1 is a case where the number of resistance elements is two. For example, when the detection voltage value V of the voltage detection circuit 24 becomes V1 or less, the switch switching control circuit 28 turns on the second switch element 36, The second resistance element 35 is connected in parallel to the first resistance element 33. At this time, if the first resistance element 33 and the second resistance element 35 have the same resistance value, the resistance value is halved, so that the load modulation intensity can be doubled.

  That is, for example, if the values of the first resistor element 33 and the second resistor element 35 are the same, when the second switch element 36 is on, the first resistor element 33 and the second resistor element connected in parallel are connected. Since the combined resistance value of the resistance element 35 is almost halved, the level of load modulation is about twice that of when the second switch element 36 is off.

  This is because the level of the signal returned to the non-contact type IC card reader / writer 12 is approximately doubled, and therefore the distance between the non-contact type IC card reader / writer 12 and the antenna 17 of the non-contact type IC card 11. If the distance between the contactless IC card reader / writer 12 and the antenna 17 of the contactless IC card 11 is far from the resonance frequency and the coupling is weak, the contactless IC card 11 may contact the contactless IC card. It is possible to avoid a state in which the non-contact type IC card reader / writer 12 cannot reproduce a signal when a case where the reply level to the reader / writer 12 becomes small occurs.

FIG. 4 is a configuration diagram of the load modulation circuit 27 in the case where a plurality of second resistance elements 35 and a plurality of second switch elements 36 are provided. Reference numerals 35 1 to 35 n denote the second resistance element 35, and 36 1 to 36 n denote the second switch element.

  The operation in the case of FIG. 4 will be described below with reference to the flowchart shown in FIG. 5 and FIG.

First, it is checked whether or not the detection voltage value V of the voltage detection circuit 24 is V1 or more (step S1). If the detection voltage value V is V1 or more, the second switch elements 36 1 to 36 n are off, Only one resistance element 33 is assumed (step S2). In this state, modulation is performed by turning on and off the first switch element 34.

If the detection voltage value V is equal to or lower than V1 as a result of the check in step S1, it is checked whether or not the detection voltage value V is [V2 ≦ V <V1] (step S3), and the detection voltage value V is [V2 ≦ V < for V1], the switch switching control circuit 28 and the second switching element 36 1 is turned on, with respect to the first resistance element 33 connected in parallel a second resistance element 35 1, the first resistance element 33 The load modulation intensity of the resistance value of the second resistance element 351 1 connected in parallel is set (step S4). In this state, modulation is performed by turning on and off the first switch element 34.

If the detection voltage value V is not [V2 ≦ V <V1] as a result of the check in step S3, it is checked whether or not the detection voltage value V is [V3 ≦ V <V2] (step S5). In the case of [V3 ≦ V <V2], the switch switching control circuit 28 turns on the second switch elements 36 1 and 36 2, and the second resistor elements 35 1 and 35 2 are connected to the first resistor element 33. The load resistance of the resistance value of the first resistance element 33 and the second resistance elements 35 1 and 35 2 connected in parallel is set in parallel (step S6). In this state, modulation is performed by turning on and off the first switch element 34.

Similarly, it is checked whether or not the detected voltage value V is [Vn + 1 ≦ V <Vn] (step S7). If the detected voltage value V is [Vn + 1 ≦ V <Vn], the switch switching control circuit 28 The switch elements 36 1 to 36 n are turned on, the second resistor elements 35 1 to 35 n are connected in parallel to the first resistor element 33, and the first resistor element 33 and the second resistor element 35 1 are connected. The load modulation intensity is set to a resistance value of ~ 35 n connected in parallel (step S8). In this state, modulation is performed by turning on and off the first switch element 34.

  As a result of the check in step S7, if the detected voltage value V is not [Vn + 1 ≦ V <Vn], communication is impossible and error processing (for example, notification that communication is impossible or communication is impossible, so contactless type) Guidance is displayed to shorten the distance between the IC card 11 and the non-contact IC card reader / writer 12) (step S9).

In the above operation, if all the resistance values of the first resistance element 33 and the second resistance elements 35 1 to 35 n are the same, the load modulation intensity can be finally increased n times. Represents. It goes without saying that the effect of the present embodiment can be obtained most if the load modulation intensity is increased within the voltage range in which the non-contact type IC card 11 can operate.

  As described above, according to the above embodiment, when data communication is performed with the non-contact type IC card reader / writer 12, the voltage value after rectifying and smoothing the carrier wave is detected, and the detected voltage value is obtained. By providing means for changing the load modulation intensity accordingly, the non-contact type IC card reader / writer 12 avoids a state in which the non-contact type IC card 11 returns, that is, data cannot be reproduced due to insufficient load modulation level. Thus, the communication characteristics of the non-contact type IC card reader / writer 12 and the non-contact type IC card 11 can be greatly improved.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 11 ... Non-contact type IC card, 12 ... Non-contact type IC card reader / writer (external device), 13 ... Resonance circuit, 14 ... IC chip, 15 ... IC module, 16 ... IC card body, 17 ... Antenna coil, 18 ... tuning capacitor, 21 ... full-wave rectifier circuit, 22 ... smoothing circuit (for example, capacitor), 23 ... regulator (power generation means), 24 ... voltage detection circuit (voltage detection means), 25 ... reception circuit, 26 ... transmission circuit , 27 ... load modulation circuit, 28 ... switch changeover control circuit (switch control means), 29 ... control unit (information processing means), 30 ... ROM, 31 ... RAM, 32 ... nonvolatile memory, 33 ... first resistance element (First load element), 34 ... first switch element, 35 ... second resistance element (second load element), 36 ... second switch element, 35 1 to 35 n ... second Resistance elements (second load elements), 36 1 to 36 n ... Second switch elements.

Claims (3)

  1. In a non-contact portable electronic device that performs non-contact data communication with an external device,
    A resonance circuit comprising an antenna coil and a tuning capacitor for wireless communication with an external device;
    A rectifier circuit connected to the resonance circuit and rectifying an electromagnetic wave transmitted from the external device received by the resonance circuit;
    Power generation means for generating an operating voltage of the portable electronic device from the output of the rectifier circuit;
    Voltage detection means for detecting the output voltage of the rectifier circuit;
    A receiving circuit for reproducing received data based on the output of the rectifier circuit;
    Information processing means for performing predetermined information processing based on received data obtained from the receiving circuit, generation of transmission data, and the like;
    A first load element connected between one of the output ends of the rectifier circuit and a ground potential;
    A first switch element connected in series to the first load element;
    A transmission circuit for controlling opening and closing of the first switch element according to transmission data from the information processing means;
    A second load element connected in parallel to the first load element;
    A second switch element connected in series to the second load element;
    Switch control means for controlling opening and closing of the second switch element according to the voltage value detected by the voltage detection means;
    A non-contact type portable electronic device characterized by comprising:
  2.   There are a plurality of the second load elements and a plurality of the second switch elements, and the switch control means selectively controls opening / closing of the plurality of second switch elements according to the voltage value detected by the voltage detection means. The contactless portable electronic device according to claim 1.
  3. In a non-contact IC card that performs data communication with an external device in a non-contact manner,
    A resonance circuit comprising an antenna coil and a tuning capacitor for wireless communication with an external device;
    A rectifying circuit connected to the resonance circuit and rectifying an electromagnetic wave transmitted from the external device received by the resonance circuit; and a power generation means for generating an operating voltage of the portable electronic device from an output of the rectification circuit; A voltage detection means for detecting an output voltage of the rectifier circuit, a receiver circuit for reproducing received data based on the output of the rectifier circuit, and predetermined information processing and transmission data based on the received data obtained from the receiver circuit. Information processing means for generating, etc., a first load element connected between one of the output terminals of the rectifier circuit and the ground potential, and a first switch connected in series to the first load element An element, a transmission circuit for controlling opening / closing of the first switch element in accordance with transmission data from the information processing means, and a second load element connected in parallel to the first load element A second switch element connected in series to the second load element; and a switch control means for controlling opening and closing of the second switch element in accordance with a voltage value detected by the voltage detection means. An IC chip configured with
    An IC card body containing the IC chip;
    A non-contact type IC card comprising:
JP2010290993A 2010-12-27 2010-12-27 Non-contact type portable electronic device and non-contact type ic card Pending JP2012138007A (en)

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JP2010290993A JP2012138007A (en) 2010-12-27 2010-12-27 Non-contact type portable electronic device and non-contact type ic card

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11345292A (en) * 1998-06-02 1999-12-14 Matsushita Electric Ind Co Ltd Non-contact ic card
JP2009302953A (en) * 2008-06-13 2009-12-24 Toshiba Corp Noncontact data communications device

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11345292A (en) * 1998-06-02 1999-12-14 Matsushita Electric Ind Co Ltd Non-contact ic card
JP2009302953A (en) * 2008-06-13 2009-12-24 Toshiba Corp Noncontact data communications device

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