JP2006059023A - Portable electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a non-contact IC card from being disabled only by a response to an initial command from an external device for stabilizing a communication condition between the non-contact IC card and the external device and preventing occurrence of a problem of communication control. <P>SOLUTION: A voltage generated by a received radio wave is monitored and compared with a previously set voltage value allowing a normal operation. While the voltage value generated by the received radio wave does not reach the normal operation allowing voltage value, the non-contact IC card is prevented from performing initial response to an initial command from the external device, or the insufficiency of received electric power is notified to the external device as a response to the initial command. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a portable electronic device such as a batteryless non-contact IC card that operates by receiving radio waves transmitted from an external device and generating an operating voltage from the received radio waves.

  In recent years, non-contact type IC cards as portable electronic devices have become battery-less because of the need for battery replacement work, miniaturization, cost reduction, long life, and the like. Therefore, recent contactless IC cards operate by receiving radio waves transmitted from a card reader / writer as an external device, generating an operating voltage from the received radio waves, and supplying the operation voltage to each unit as operating power. It has become.

  In this type of non-contact type IC card, for example, various processes are executed in accordance with a command transmitted from an external device. Processing corresponding to commands from such an external device includes processing with a low load (processing with low power consumption) and processing with a large load (processing with high power consumption). For this reason, depending on the level of the operating voltage generated from the received radio wave, a command that performs a process with a small load may be supported, but a command that performs a process with a large load may not be supported. For example, the initial response to the initial command consumes less power in the non-contact IC card. For this reason, there is a possibility that the initial response to the initial command can be executed even if the level of the operating voltage generated from the radio wave received by the non-contact IC card is insufficient. On the other hand, processing for commands other than the initial command (for example, data read request command, data write request command, authentication request command, etc.) consumes a large amount of power in the non-contact IC card. For this reason, processing for commands other than the initial command may not be executed unless the level of the operating voltage generated from the radio wave received by the non-contact IC card is sufficient.

However, in the conventional non-contact type IC card, if the generated voltage is a level at which an initial response is possible, an initial response to an initial command from an external device is performed. In this case, if the generated voltage level is not sufficient, it may not be possible to deal with a command that performs processing with a large load even though the initial response is transmitted. In such a case, the external device that transmitted the initial command determines that there is a non-contact type IC card based on the initial response to the initial command. For this reason, although the external device continues the communication state with the non-contact type IC card, there may be a situation in which there is no response from the non-contact type IC card for a command accompanied by a heavy load process. There is sex. In such a case, there is a problem that a problem occurs in processing in an external device or processing in a non-contact type IC card.
JP-A-9-161026

  In order to solve the above-described problems, an object of the present invention is to provide a portable electronic device that can perform stable processing on a command from an external device.

  The portable electronic device according to the present invention includes a receiving unit that receives a radio wave from an external device, a voltage generating unit that generates a voltage from the radio wave received by the receiving unit, a voltage value generated by the voltage generating unit, and a voltage value generated in advance. When it is determined that the voltage value generated by the voltage generation unit is smaller than a preset voltage value by the voltage detection unit that compares the set voltage value with the voltage detection unit, the external device And a control means that does not output a response.

  A portable electronic device according to the present invention includes a first circuit that operates at a first voltage value or more, a second circuit that operates at a second voltage value that is greater than the first voltage value, and an external device. Receiving means for receiving a radio wave from the voltage generator, a voltage generating means for generating a voltage from the radio wave received by the receiving means, a value of the voltage generated by the voltage generating means by the voltage generating means, and the first voltage value And voltage detection means for comparing the voltage value generated by the voltage generation means with the second voltage value, and the voltage value generated by the voltage generation means by the voltage detection means is the first voltage value. Switching means for setting the first circuit to an operable state and the second circuit to an inoperable state when it is determined that the voltage value is equal to or greater than the second voltage value and smaller than the second voltage value. .

  The present invention can provide a portable electronic device that can perform stable processing on a command from an external device.

The best mode for carrying out the present invention will be described with reference to the drawings.
First, a non-contact type IC card 10 according to an embodiment of the present invention will be described.
A contactless IC card 10 according to an embodiment of the present invention is a portable electronic device that performs wireless communication with an external device, and performs various processes in accordance with commands from the card reader / writer 1 as the external device. It is something to execute.

FIG. 1 is a block diagram schematically showing a configuration example of a non-contact type IC card 10.
As shown in FIG. 1, the non-contact type IC card 10 includes functions such as a transmission / reception antenna unit 11, a modem unit 12, a CPU 13, a coprocessor 14, a memory 15, and a power generation unit 16. For example, the units 12 to 16 that realize these functions are stored in one IC chip except for the transmission / reception antenna unit 11, and are embedded in the housing of the non-contact type IC card 10.

  The CPU 13 controls the entire contactless IC card 10. The CPU 13 performs various data processing and overall control of the non-contact type IC card 10. The coprocessor 14 encrypts and decrypts various data. The memory 15 is composed of a rewritable nonvolatile memory or the like, and stores various data. For example, the memory 15 is composed of a nonvolatile memory such as an EEPROM or a flash ROM.

  The transmission / reception antenna unit 11 is configured by a loop antenna or the like, and performs transmission / reception of radio waves. The transmitting / receiving antenna unit 11 transmits radio waves to the card reader / writer 1 and receives radio waves from the card reader / writer. The modulation / demodulation unit 12 modulates transmission data to be transmitted to the card reader / writer 1 as an external device by the transmission / reception antenna unit 11 or receives radio waves received from the card reader / writer 1 as an external device by the transmission / reception antenna unit 11. Demodulate data. The power generation unit 16 generates a power supply voltage for operation of the contactless IC card. For example, the power generation unit 16 generates a stabilized DC voltage by rectifying and smoothing the radio wave received by the transmission / reception antenna unit 11 with a rectifier circuit, and the DC voltage is set as a predetermined constant operating voltage. It supplies to each part in the contact-type IC card 10.

Next, a specific circuit configuration example in the non-contact type IC card 10 will be described.
FIG. 2 is a diagram illustrating a circuit configuration example in the non-contact type IC card 10.
As shown in FIG. 2, a non-contact IC card 10 includes a transmitting / receiving antenna 21, a tuning capacitor (C1) 22, a rectifying bridge circuit 23, a smoothing capacitor (C2) 24, a shunt regulator 25, and a voltage detection circuit 26. A first load circuit 28, a second load circuit 29, a reset generation circuit 210, a clock generation circuit 211, and the like are provided.

  The transmission / reception antenna 21 transmits / receives radio waves to / from the card reader / writer 1. The tuning capacitor 22 is tuned to a frequency at which the transmission carrier frequency (power wave) received by the transmitting / receiving antenna 21 can be induced. That is, the transmission / reception antenna 21 and the tuning capacitor 22 form an LC resonance circuit, and generate an AC voltage by inducing transmission power from the card reader / writer 1.

  This AC voltage is full-wave rectified by the rectification bridge circuit 23. The voltage that has been full-wave rectified by the rectifier bridge circuit 23 becomes a DC voltage (V1) smoothed by the smoothing capacitor 24. The DC voltage V1 is a voltage that changes depending on the strength of the radio wave (power received by the radio wave) received by the contactless IC card 10. Therefore, when the power received from the card reader / writer 1 by radio waves is strong, the DC voltage V1 increases. When the power received from the card reader / writer 1 by radio waves is weak, the DC voltage V1 decreases. The shunt regulator 25 supplies the DC voltage V1 as described above to each part in the non-contact type IC card 10 as a predetermined constant internal circuit operating voltage (Vcc).

  The transmission carrier signals from the card reader / writer 1 are generated at both terminals of the transmitting / receiving antenna 21 with a phase difference of 180 degrees. In the circuit configuration example shown in FIG. 2, a clock generation circuit 211 is connected to one terminal of the transmission / reception antenna 21. The clock generation circuit 211 may be connected to either terminal of the transmission / reception antenna 21. The clock generation circuit 211 converts the transmission carrier signal from the card reader / writer 1 into a logic level clock signal. The clock signal generated by the clock generation circuit 211 is used as all operation clock signals in the non-contact type IC card 10.

  The voltage detection circuit 26 detects the value of the voltage generated from the received radio wave, and always monitors the DC voltage V1 as the output of the rectification bridge circuit 23. The voltage detection circuit 26 compares the voltage value generated from the received radio wave with a preset voltage value, and outputs the comparison result. In this embodiment, the voltage detection circuit 26 is set with a first voltage value and a second voltage value larger than the first voltage value as will be described later. The voltage value generated from the received radio wave is compared with the first voltage value, the voltage value generated from the received radio wave is compared with the second voltage value, and a signal indicating the comparison result is output. It is assumed that

  The reset generation circuit 210 generates reset signals for the first load circuit 28 and the second load circuit 29. The reset generation circuit 210 generates and outputs a reset signal for the first load circuit 28 or the second load circuit 29 based on the output from the voltage detection circuit 26. The reset signal generated by the reset generation circuit 210 is a signal for selectively switching the operation state of the first load circuit 28 and the operation state of the second load circuit 29. That is, the operation state (reset state or reset release state) of the first load circuit 28 and the operation state (reset state or reset release state) of the second load circuit 29 are determined by the reset signal from the reset generation circuit 210. Switched.

  The first load circuit 28 is a circuit that performs a light load operation (processing with low power consumption) such as an initial response to an initial command from the card reader / writer 1. On the other hand, the second load circuit 29 operates with a larger load than the first load circuit 28 that is executed using, for example, a CPU, a coprocessor, a memory, or the like (a process with high power consumption). It is a circuit which performs.

  For example, the first load circuit 28 is a load circuit that operates with a small amount of power consumption, which is composed of only a logic circuit. In the configuration example shown in FIG. 1, the first load circuit 28 includes only the modem unit 12 or only the modem unit 12 and the CPU 13, and responds to an initial command as a simple response request command from the card reader / writer 1. This circuit outputs an initial response as a simple response.

  The second load circuit 29 is a load circuit that operates with higher power consumption than the first load circuit 28. In the configuration example shown in FIG. 1, the second load circuit 29 includes a CPU 13, a coprocessor 14, a memory 15, a modem unit 12, and the like, and commands other than the initial command from the card reader / writer 1 (for example, data Read request command, data write request command, authentication request command, etc.), and processing corresponding to each command is performed, and the processing result is output as a response to the command transmission source.

Next, operations of the first load circuit 28 and the second load circuit 29 with respect to a voltage generated from the received radio wave will be described.
FIG. 3 is a diagram showing the relationship between the voltage value detected by the voltage detection circuit 26 (the value of the DC voltage (rectified voltage) generated from the received radio wave) V1 and the elapsed time. In FIG. 3, the minimum voltage value required for the first load circuit 28 to operate is the first voltage value RST1, and the minimum voltage value required for the second load circuit 29 to operate is the first voltage value RST1. It is shown as a voltage value RST2 of 2. Note that the second voltage value RST2 is at least larger than the first voltage value RST1.

  Further, as described above, it is assumed that the first voltage value RST1 and the second voltage value RST2 are set in the voltage detection circuit 26. Therefore, in the voltage detection circuit 26, the reset generation circuit 210 generates a signal indicating what value the DC voltage V1 generated from the received radio wave is with respect to the first voltage value RST1 and the second voltage value RST2. Output to. In response to the output from the voltage detection circuit 26, the reset generation circuit 210 selectively cancels the reset state of the first load circuit 28 and the second load circuit 29. Note that the reset state is a state in which the circuit is not operated (operation stop state), and the circuit is operable by releasing the reset state.

  As shown in FIG. 3, the DC voltage V1 normally increases with time. In FIG. 3, when the voltage V1 is smaller than the first voltage value RST1, neither the first load circuit 28 nor the second load circuit 29 is operable. Further, when the DC voltage V1 is equal to or higher than the first voltage value RST1 and smaller than the second voltage value RST2, the first load circuit 28 is operable or the second load circuit 29 is inoperable. is there. Further, when the DC voltage V1 is equal to or higher than the second voltage value RST2, both the first load circuit 28 and the second load circuit 29 can be operated (that is, the non-contact type IC card 10 can be normally operated). State).

  For example, when the voltage V1 is RST1 ≦ V1 <RST2, the voltage detection circuit 26 outputs a signal indicating that the voltage V1 is equal to or higher than the first voltage value RST1 and smaller than the second voltage value RST2. To supply. In this case, the reset generation circuit 210 generates a reset signal for releasing the reset state of the first load circuit 28 and outputs the reset signal to the first load circuit 28. When the voltage V1 is RST2 ≦ V1, the voltage detection circuit 26 supplies a signal indicating that the voltage V1 is equal to or higher than the second voltage value RST2 to the reset generation circuit 210. In this case, the reset generation circuit 210 generates a reset signal for releasing the reset state of the second load circuit 29 and outputs the reset signal to the second load circuit 29.

Hereinafter, the state in the non-contact type IC card 10 based on the magnitude relationship between the first voltage value RST1 and the second voltage value with respect to the DC voltage V1 will be described in detail.
First, the case where the voltage value V1 detected by the voltage detection circuit 26 is smaller than the first voltage value RST1 (that is, the case of “V1 <RST1”) will be described in detail.
In this case, the DC voltage V1 is smaller than the first voltage value RST1. For this reason, the first load circuit 28 is inoperable. Of course, the second load circuit is also inoperable. In other words, the voltage generated from the radio wave transmitted from the card reader / writer 1 as an external device is insufficient as the voltage at which the non-contact IC card 10 operates. For this reason, the non-contact type IC card 10 is not activated and does not operate at all.

Next, when the voltage value V1 detected by the voltage detection circuit 26 is equal to or higher than the first voltage value RST1 and smaller than the second voltage value RST2 (that is, in the case of “RST1 ≦ V1 <RST2”). This will be described in detail.
In this case, the DC voltage V1 is equal to or higher than the first voltage value RST1. For this reason, the first load circuit 28 is operable. However, the DC voltage V1 is smaller than the second voltage value RST2. For this reason, the second load circuit 29 cannot operate. In other words, when RST1 ≦ V1 <RST2, the initial response to the initial command executed by the first load circuit 28 can be executed, but the process for the command executed by the second load circuit 29 cannot be executed. That is, in the case of RST1 ≦ V1 <RST2, the DC voltage V1 is a voltage that allows an initial response to an initial command, but is not a voltage that can perform a process or a response to a next command with large power consumption.

  In this case, the voltage detection circuit 26 supplies a signal indicating that the DC voltage V1 is equal to or higher than the first voltage value RST1 and smaller than the second voltage value RST2 to the reset generation circuit 210. Upon receiving this signal, the reset generation circuit 210 generates a reset signal for releasing the reset state of the first load circuit 28 and supplies the reset signal to the first load circuit 28.

  As a result, the reset state (operation stop state) of the first load circuit 28 is released, and only the first load circuit 1 can operate. In this case, power is supplied to the second load circuit 29, but it does not operate because of a reset state (operation stop state). For this reason, the second load circuit 29 does not consume power. Since the first load circuit 28 is composed of a circuit with low power consumption as described above, the first load circuit 28 can sufficiently operate with low received power (RST1 ≦ V1 <RST2).

  Further, in this case, the DC voltage V1 is a voltage that allows the non-contact IC card 10 to respond to an initial command from the card reader / writer 1 in an initial response, but is insufficient as a voltage necessary for command processing with large power consumption. is doing. For this reason, the CPU 13 of the non-contact type IC card 10 performs control so that an initial response to the initial command from the card reader / writer 1 is not transmitted. When the card reader / writer 1 receives an initial response from the non-contact type IC card in response to the initial command, it performs communication control with the non-contact type IC card assuming that the non-contact type IC card exists. Because. In such a case, there is a possibility that the communication state between the card reader / writer 1 and the non-contact type IC card 10 becomes unstable and a problem occurs.

  In this case, the non-contact type IC card 10 may transmit that the power is insufficient as a response to the initial command from the card reader / writer 1. Here, the power is insufficient means that the voltage generated from the received radio wave does not reach the voltage (normally operable operating voltage) for operating the second load circuit 29. . In this case, the card reader / writer 1 that has received the response as described above increases the power supplied to the non-contact type IC card 10 (radio wave to be transmitted), or the voltage generated by the non-contact type IC card 10 is a predetermined voltage. It is possible to perform operations such as waiting until the voltage is reached (waiting for the next command to be transmitted).

  Next, the case where the voltage value V1 detected by the voltage detection circuit 26 is greater than or equal to the second voltage value RST2 (that is, the case of “RST2 ≦ V1”) will be described in detail.

  In this case, the voltage V1 is not less than the second voltage value RST2. For this reason, electric power sufficient to operate the second load circuit 29 is supplied. Of course, the first load circuit 28 is also operable. In other words, the voltage generated from the radio wave transmitted from the card reader / writer 1 as an external device is sufficient as the voltage at which the noncontact IC card 10 normally operates. For this reason, the non-contact type IC card 10 can operate each unit such as the CPU 13, the coprocessor 14, and the memory 15, and can perform processing (normal operation) for each command from the external device.

  The voltage detection circuit 26 supplies a signal indicating that the DC voltage V1 is equal to or higher than the second voltage value RST2 to the reset generation circuit 210. Upon receiving this signal, the reset generation circuit 210 generates a reset signal for releasing the reset state (operation stop state) of the second load circuit 29 and supplies the reset signal to the second load circuit 29. As a result, the reset state of the second load circuit 29 is released, and the second load circuit 29 becomes operable. In this case, the first load circuit 28 may be reset again (operation stop state) by a signal from the reset generation circuit 210 or may be operated in parallel with the second load circuit as a reset release state. May be.

Next, a specific operation example of the non-contact type IC card 10 will be described.
FIG. 4 is a flowchart for explaining a specific operation example of the non-contact type IC card 10.
First, the non-contact type IC card 10 receives a radio wave transmitted from the card reader / writer 1 as an external device by the transmission / reception antenna unit 11, and generates a voltage as a power source from the received radio wave (step S11). . The radio wave received from the card reader / writer 1 becomes a DC voltage (rectified voltage) V1 by a circuit configuration as shown in FIG. The DC voltage (rectified voltage) V <b> 1 is continuously generated while radio waves are received by the transmission / reception antenna unit 11.

  When the DC voltage V1 is generated from the received radio wave, the voltage detection circuit 26 compares the DC voltage value V1 generated from the radio wave with a preset voltage value. That is, in the voltage detection circuit 26, the first voltage value RST1 and the second voltage value RST2 as described above are set. Therefore, the voltage detection circuit 26 compares the voltage V1 with the first voltage value RST1, and compares the voltage V1 with the second voltage value (step S12 and step S15).

  When it is determined by this comparison that the voltage V1 is equal to or higher than the first voltage value RST1 and smaller than the second voltage value RST2 (step S12, YES), the voltage detection circuit 26 determines that the voltage V1 is the first voltage value. A signal indicating that the value is equal to or greater than the value RST1 and smaller than the second voltage value RST2 is supplied to the reset generation circuit 210. Upon receiving this signal, the reset generation circuit 210 generates a reset signal for releasing the reset state of the first load circuit 28 and supplies the reset signal to the first load circuit 28. Upon receiving this reset signal, the first load circuit 28 releases the reset state (step S13).

As a result, the first load circuit 28 becomes operable, and an initial response to an initial command executed by the first load circuit 28 is possible. In this case (when RST1 ≦ V1 <RST2), the first load circuit 28 does not transmit an initial response to the initial command from the card reader / writer 1 as an external device (step S14).
In addition, when RST1 ≦ V1 <RST2, the first load circuit 28 indicates that the received power is insufficient for normal operation with respect to the initial command from the card reader / writer 1 as an external device. A response may be transmitted (step S14).

  When RST1 ≦ V1 <RST2, the contactless IC card 10 is in a state in which only the operation of the first load circuit 28 is possible and the second load circuit is inoperable. Therefore, the voltage detection circuit 26 monitors the voltage V1 until the voltage generated from the received radio wave becomes equal to or higher than RST2.

  When it is determined that the voltage V1 is equal to or higher than the second voltage value RST2 (step S15, YES), the voltage detection circuit 26 outputs a signal indicating that the voltage V1 is equal to or higher than the second voltage value RST2. This is supplied to the reset generation circuit 210. Upon receiving this signal, the reset generation circuit 210 generates a reset signal for releasing the reset state of the second load circuit 29 and supplies the reset signal to the second load circuit 29. Receiving this reset signal, the second load circuit 29 releases the reset state (step S16).

  As a result, the second load circuit 29 becomes operable, and normal operation such as processing and response to various commands executed by the second load circuit 29 becomes possible. In this case (when RST2 ≦ V1), the second load circuit 29 performs normal operations in response to various commands from the card reader / writer 1 as an external device (step S17).

  As described above, the contactless IC card of the present embodiment monitors the voltage generated from the received radio wave, compares it with a preset normal operable voltage value, and generates it from the received radio wave. When the measured voltage does not reach the normal operable voltage, only the lightly loaded circuit in the non-contact type IC card can be operated, and when the normal operating voltage is reached, the load in the non-contact type IC card. It is designed to operate a heavy circuit.

  In other words, while the voltage value generated by the received radio wave does not reach the voltage value at which normal operation is possible, the non-contact IC card does not make an initial response to the initial command from the external device, or as a response to the initial command. The external device is notified that the received power is insufficient.

  As a result, it is possible to prevent the non-contact type IC card from becoming inoperable only by a response to the initial command from the external device, stabilize the communication state between the non-contact type IC card and the external device, and control communication. It is possible to prevent problems from occurring.

1 is a block diagram schematically showing the configuration of a non-contact IC card according to an embodiment of the present invention. The figure which shows the circuit structural example in a non-contact-type IC card. The figure which shows the example of a setting of the 1st voltage value with respect to the voltage produced | generated from an electromagnetic wave, and a 2nd voltage value. The flowchart for demonstrating the specific operation example of a non-contact-type IC card.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Card reader / writer (external device), 10 ... Non-contact IC card (portable electronic device), 11 ... Transmission / reception antenna part (reception means), 12 ... Modulation / demodulation part, 13 ... CPU (control means), 14 ... Co Processor, 15 ... Memory, 16 ... Power supply generation unit (voltage generation means), 21 ... Transmission / reception antenna, 22 ... Tuning capacitor, 23 ... Rectification bridge circuit, 24 ... Smoothing capacitor, 25 ... Shunt regulator, 26 ... Voltage detection circuit (Voltage detection means), 28 ... first load circuit (first circuit), 29 ... second load circuit (second circuit), 210 ... reset generation circuit (switching means), 211 ... clock generation circuit, RST1 ... first voltage value, RST2 ... second voltage value, V1 ... DC voltage (rectified voltage)

Claims (5)

Receiving means for receiving radio waves from an external device;
Voltage generating means for generating a voltage from the radio wave received by the receiving means;
Voltage detection means for comparing the voltage value generated by the voltage generation means with a preset voltage value;
When it is determined that the voltage value generated by the voltage generation means is smaller than a preset voltage value by the voltage detection means, a control means that does not output a response to the external device;
A portable electronic device comprising: A first circuit operating at or above a first voltage value;
A second circuit operating at or above a second voltage value greater than the first voltage value;
Receiving means for receiving radio waves from an external device;
Voltage generating means for generating a voltage from the radio wave received by the receiving means;
A voltage for comparing the voltage value generated by the voltage generating means with the first voltage value and for comparing the voltage value generated by the voltage generating means with the second voltage value by the voltage generating means. Detection means;
A state in which the first circuit is operable when it is determined by the voltage detection means that the value of the voltage generated by the voltage generation means is greater than or equal to the first voltage value and smaller than the second voltage value. Switching means for making the second circuit inoperable; and
A portable electronic device comprising: The switching means further sets the second circuit in an operable state when it is determined that the voltage value generated by the voltage generation means is equal to or higher than the second voltage value by the voltage detection means. The portable electronic device according to claim 2, wherein: And a control means for outputting a response to the external device by the first circuit when the voltage detection means determines that the voltage value generated by the voltage generation means is equal to or greater than the second voltage value. The portable electronic device according to claim 2, further comprising: Further, when it is determined that the value of the voltage generated by the voltage generation means by the voltage detection means is equal to or higher than the first voltage value and smaller than the second voltage value, the state operable by the switching means 3. The portable electronic device according to claim 2, further comprising: a control unit that outputs a response indicating that the power received by the first circuit by the first circuit is insufficient. apparatus.

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