JP2005191961A - Noncontact ic card, electronic information apparatus, portable electronic information apparatus, open-type system, method for controling electric power consumption, control program, and readable recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accelerate processing when magnetic field intensity is high, and to be operable even when the magnetic field intensity is low. <P>SOLUTION: In a noncontact IC card 10 for obtaining operation power by communicating by a magnetic field by using an antenna means 1, a power detection circuit 6 detects the power consumption level of an integrated circuit with respect to a reception power level, and a clock selection circuit 7 heightens an operation clock frequency when power consumption is high and lowers the operation clock frequency when power consumption is low to optimize the reception power and current consumption. In an adhesion type system capable of receiving a ferromagnetic field, a clock frequency is accelerated for accelerating processing. In an open-type system changing from a state where the received power is weak to a state where the received power is strong, power consumption is lowered in a weal magnetic field to extend operation time in a wider range, and processing speed is accelerated in an intense magnetic field to reduce a time of physical feeling. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a non-contact type IC card that communicates with an external device such as an IC card reader / writer by a magnetic field and acquires operating power for operating an integrated circuit, an electronic information device having this function, and a portable electronic information device, The present invention relates to an open type system using the same, a power consumption control method thereof, a control program for causing a computer to execute the control method, and a readable recording medium on which the program is recorded.

  This type of non-contact type IC card is provided with antenna means. The antenna means receives a surrounding magnetic field to generate a voltage or a current, and obtains operating power for operating the integrated circuit through a tuning capacitor, a rectifier, a power supply circuit, and the like.

  In addition, communication is performed with an external device such as an IC card reader / writer via the antenna means. For example, an instruction signal received from the external means is demodulated by a modulation / demodulation circuit and integrated. Data is read / written from / to a memory inside the circuit (IC chip), and various arithmetic processes are performed by a CPU (central processing unit) inside the integrated circuit to perform an authentication operation.

  In a conventional non-contact type IC card, a clock signal for operating an internal integrated circuit is, for example, a method based on carrier extraction as disclosed in Patent Document 1 (clock signal received by antenna means is clocked). For example, a method of extracting a clock signal by a separation circuit) and a method of generating by providing an oscillator inside an IC card.

Here, the operation clock frequency itself of the integrated circuit is almost fixed as a specification. Even when the operating clock frequency can be changed, it is necessary to control the operating clock frequency by communication from an external terminal device or the like.
Japanese Patent Laid-Open No. 10-320510

  In recent years, as the use of IC cards for electronic payments has increased, advanced cryptographic functions and the like have been mounted on IC cards, and the power consumption of IC cards has increased compared to the conventional ones. Further, non-contact type IC cards have been used for touch-and-go systems such as commuter passes, and demands for remote operation and high-speed processing from IC card readers / writers are increasing.

  By the way, it is known that the power consumption decreases as the operation clock frequency of the integrated circuit decreases. Further, it is known that the wireless magnetic field strength of the IC card reader / writer decreases as the distance from the reader / writer antenna end increases, and the received power level of the IC card decreases as the magnetic field strength decreases. Further, when the magnetic field received by the non-contact type IC card is insufficient with respect to the operating power, the processing operation is reset due to power shortage even during the processing operation by the IC card.

  When the operation clock frequency is fixed as in the conventional integrated circuit, the limit on the distance from the IC card reader / writer capable of operating the non-contact type integrated circuit is determined at the time of design.

  In order to increase the operating distance from the IC card reader / writer of the non-contact type integrated circuit, when the operating frequency is set low from the beginning, the processing speed is inevitably slowed down. This results in a queue at the entrance / exit gate, which is a fatal problem.

  Also, in the method of externally controlling the change of the operation clock frequency of the non-contact type integrated circuit, it is necessary to provide information from the IC card to the external terminal device once, and the operation clock frequency of the IC card in a form that responds to it. Will be changed. In this case, the processing by the IC card is temporarily stopped until the clock frequency change command is supplied from the outside, resulting in an increase in processing time. Even when power supply is sufficient, it is necessary to give a clock frequency change command to the IC card from the outside.

  The present invention solves the above-described conventional problems, and without causing processing stoppage due to wireless communication with the outside, enables high-speed processing operation by increasing the operating clock frequency in a high magnetic field, and operating clock frequency in a low magnetic field. , Low-power processing and low-speed processing operation is possible, and the operating distance from the IC card reader / writer can be extended, a non-contact IC card, an electronic information device having this function, and a portable electronic information device, An object of the present invention is to provide an open type system using the same, a power consumption control method thereof, a control program for causing a computer to execute the method, and a readable recording medium on which the control program is recorded.

  The non-contact type IC card of the present invention has an antenna means and an integrated circuit that generate a voltage or current by receiving a surrounding radio magnetic field, and an operating power for operating the integrated circuit using the antenna means. In a non-contact type IC card that acquires communication and enables communication with an external device, the relative magnitude between the received power level received from the surrounding wireless magnetic field and the power consumption level consumed inside the integrated circuit Depending on the relationship, the power consumption level has clock control means for controlling the operation clock frequency inside the integrated circuit so that the power consumption level falls within a predetermined range including the received power level as a maximum value. Achieved.

  Preferably, the clock control means in the contactless IC card of the present invention controls the operation clock frequency inside the integrated circuit so that the power consumption level matches the received power level.

  Further preferably, the clock control means in the non-contact type IC card of the present invention is configured so that the power consumption level consumed in the integrated circuit is smaller than the predetermined range with respect to the received power level. When the operating clock frequency is increased and the power consumption level is greater than the predetermined range, the operation clock frequency inside the integrated circuit is controlled to be lowered.

  Further preferably, the clock control means in the non-contact type IC card of the present invention selects one from a plurality of clock signals having different frequencies.

  Further preferably, the clock control means in the non-contact type IC card of the present invention is based on a determination means for determining the relative magnitude relationship, and a determination result of the magnitude relation, executed based on a control program. Clock frequency control means for controlling an operation clock frequency inside the integrated circuit so that the power consumption level falls within the predetermined range.

  Further preferably, the clock control means in the non-contact type IC card of the present invention comprises a clock control circuit for controlling an operation clock frequency of the integrated circuit.

  Further preferably, the clock control circuit in the contactless IC card of the present invention has a power consumption level when the power consumption level consumed inside the integrated circuit is smaller than the predetermined range with respect to the power reception power level. A power detection circuit that outputs a control signal according to when the level is greater than the predetermined range, and a power consumption level consumed inside the integrated circuit with respect to the received power level according to the control signal; Select one of a plurality of clock signals so that the operating clock frequency inside the integrated circuit is increased when the power consumption level is lower than the predetermined range, and the operating clock frequency inside the integrated circuit is decreased when the power consumption level is higher than the predetermined range. And a clock selection circuit.

  Further preferably, in the contactless IC card of the present invention, a tuning capacitor connected in parallel to the antenna means to constitute a parallel resonance circuit, and an AC voltage received by the antenna means connected to both ends of the antenna means A rectifier circuit for converting a DC voltage into a DC voltage, a power supply circuit having an input section connected to an output section of the rectifier circuit to stabilize a power supply current and supplying the same to the integrated circuit, an input basic clock signal, and the input basic clock signal A frequency dividing circuit that outputs a clock signal having a plurality of frequencies divided, and the power detection circuit compares the power supply control potential in the power supply circuit with a preset reference voltage to compare the received power The clock selection circuit determines a relative magnitude relationship between the level and the power consumption level, and the clock selection circuit determines a plurality of clocks output from the frequency divider circuit based on the determination result of the magnitude relationship. Supplied to the integrated circuit by selecting one from the click signal.

  Further preferably, the power supply circuit in the non-contact type IC card of the present invention is a series type power supply circuit or a shunt type power supply circuit in which a power supply current is output-controlled in accordance with the power supply control potential.

  Further, preferably, a plurality of reference voltages are set in the non-contact type IC card of the present invention.

  Further, preferably, the reference voltage in the non-contact type IC card of the present invention can be switched.

  Further preferably, the antenna means in the non-contact type IC card of the present invention is a loop antenna.

  Further preferably, the integrated circuit in the non-contact type IC card of the present invention is an IC chip.

  An open type system according to the present invention is a non-contact type IC card according to any one of claims 1 to 13 and a non-contact type IC card brought close to the non-contact type IC card by non-contact data reading and data by communication using a wireless magnetic field. IC card reader / writer means for performing at least one of the writing operations, thereby achieving the above object.

  The electronic information device of the present invention has an antenna means and an integrated circuit that generate a voltage or current by receiving a surrounding wireless magnetic field, and obtains operating power for operating the integrated circuit using the antenna means. In addition, in an electronic information device that enables communication with an external device, depending on the relative magnitude relationship between the received power level received from the surrounding wireless magnetic field and the power consumption level consumed inside the integrated circuit The clock control means for controlling the operation clock frequency inside the integrated circuit so that the power consumption level falls within a predetermined range including the received power level as a maximum value, thereby achieving the above object.

  An open type system according to the present invention is a reader that performs at least one of data reading and data writing in a non-contact manner by communication with a wireless magnetic field to the electronic information device according to claim 15 and the approached electronic information device. Writer means, whereby the above object is achieved.

  The portable electronic information device of the present invention has an antenna means and an integrated circuit that generate a voltage or current by receiving a surrounding wireless magnetic field, and an operating power for operating the integrated circuit using the antenna means. In the portable electronic information device that acquires communication and enables communication with an external device, the relative magnitude between the received power level received from the surrounding wireless magnetic field and the power consumption level consumed inside the integrated circuit Depending on the relationship, the power consumption level has clock control means for controlling the operation clock frequency inside the integrated circuit so that the power consumption level falls within a predetermined range including the received power level as a maximum value. Achieved.

  An open system according to the present invention provides at least one of data reading and data writing to a portable electronic information device according to claim 17 and contacted portable electronic information device in a non-contact manner by wireless magnetic field communication. Reader / writer means for performing the above-mentioned purpose, thereby achieving the above object.

The power consumption control method according to the present invention is a power consumption control method for a non-contact type IC card according to claim 1, wherein the received power level received from the surrounding wireless magnetic field and the power consumption consumed inside the integrated circuit. A determination step for determining a relative magnitude relationship with the level;
A clock frequency control step for variably controlling the operation clock frequency inside the integrated circuit so that the power consumption level falls within the predetermined range based on the determination result of the magnitude relation, thereby achieving the object. Is done.

The power consumption control method of the present invention is a power consumption control method for a portable electronic information device according to claim 17, wherein the received power level received from the surrounding wireless magnetic field and the power consumption consumed inside the integrated circuit. A determination step for determining a relative magnitude relationship with the level;
A clock frequency control step for variably controlling the operation clock frequency inside the integrated circuit so that the power consumption level falls within the predetermined range based on the determination result of the magnitude relation, thereby achieving the object. Is done.

  The control program of the present invention causes a computer to execute each step of the power consumption control method according to claim 19 or 20, thereby achieving the above object.

  The readable recording medium of the present invention is readable by a computer in which the control program according to claim 21 is recorded, whereby the above object is achieved.

  The operation of the present invention will be described below with the above configuration.

  The non-contact type IC card of the present invention includes an antenna means (for example, a loop antenna) that generates a voltage or current by receiving a magnetic field in the surrounding (field), a received power level received from the magnetic field, and an integrated circuit (for example, an IC chip). Clock control means for controlling the operating clock frequency inside the integrated circuit according to the relative magnitude relationship with the consumed power level, and authentication operation and data writing / reading according to requests from external devices And an integrated circuit.

  The antenna means receives the magnetic field on the field generated by the IC card reader / writer means as the reader / writer means and outputs it as a voltage (or current), thereby communicating with an external device, The operating power for operating the integrated circuit is acquired. As this loop antenna, a wound antenna or an etching antenna is generally used.

  The clock control means detects the power consumption level inside the integrated circuit with respect to the received power level received from the magnetic field, and compares the detected value (detected voltage) with a preset reference value (reference voltage) by a comparator or the like. When the power consumption level is low, the operation clock frequency inside the integrated circuit is increased, and when the power consumption level is large, one of the clock signals is selected to reduce the operation clock frequency inside the integrated circuit. Control the operating clock frequency.

  At this time, by setting a plurality of reference voltages and comparing the power consumption level and the reference voltage using a plurality of comparators, the operation can be accelerated as much as possible without unnecessarily slowing the operation clock frequency. Can do. The reference voltage can be variably controlled by software (a CPU function based on a control program in a computer-readable readable recording medium) or the like.

  The contactless IC card of the present invention further includes a tuning capacitor set so that the antenna means can receive power efficiently, a rectifier that converts the AC voltage received by the antenna means into a DC voltage, and a rectifier circuit. You may have the stabilized power supply circuit which stabilizes output power supply and supplies to an integrated circuit, and the frequency divider circuit which divides | segments a basic clock signal.

  The tuning capacitor forms a parallel resonant circuit with the antenna means and other circuits, and the capacitance value is set so that a magnetic field can be efficiently received by the antenna. The capacitance value is considered including the parasitic capacitance value.

  In the rectifier, the AC voltage is converted into a DC voltage by full-wave rectification or half-wave rectification, and the converted DC voltage is input to the stabilized power supply circuit.

  The power consumption level consumed in the integrated circuit with respect to the received power level received from the magnetic field is detected by a different method depending on the configuration of the power supply circuit. For example, when a series power supply circuit is used, it is possible to detect the power consumed by the integrated circuit by detecting the voltage value input to the power supply circuit. Further, when a shunt type power supply circuit is used, it is possible to detect the power consumed by the integrated circuit by detecting the current value on the control side.

  In the clock control means, the operation clock frequency inside the integrated circuit may be controlled by hardware, or the operation clock frequency inside the integrated circuit may be controlled by software.

  When the operation clock frequency inside the integrated circuit is controlled by hardware (circuit configuration), for example, the power consumption inside the integrated circuit with respect to the received power level received from the magnetic field is detected from the power supply circuit, and the detection voltage is preset. A power detection circuit that outputs a control signal so that the operation clock frequency inside the integrated circuit is high when the detection voltage is small and the operation clock frequency inside the integrated circuit is low when the detection voltage is large. In response to a control signal output from the power detection circuit, a clock selection circuit that selects one of a plurality of clock signals to control an operation clock frequency inside the integrated circuit is provided, and operates directly on the integrated circuit. A clock signal can be supplied.

  Further, when the operation clock frequency inside the integrated circuit is controlled by software, the clock signal can be selected by software using the control signal output from the power detection circuit as an interrupt signal of software.

  If such a non-contact type IC card of the present invention is used in an open type system such as a touch-and-go system such as an entrance / exit gate or a ticket gate, the operation start time becomes faster, and the IC card reader / writer Since high-speed operation becomes possible as it approaches, the sensation speed can be further improved. The present invention can be applied not only to non-contact type IC cards but also to electronic information devices and portable electronic information devices. Similarly, an open system using the electronic information device or portable electronic information device of the present invention can be configured.

  According to the present invention, the power consumption of the integrated circuit is larger than the received power level received from the external magnetic field (for example, the received power level from the IC card reader / writer), and the integrated circuit is integrated when the received power is insufficient. By reducing the operating clock frequency in the circuit, power consumption can be reduced, and the operable area from the IC card reader / writer can be expanded. Further, when the non-contact type IC card is placed in a strong magnetic field and the received power level is sufficient, the operation clock frequency in the integrated circuit can be increased to enable high-speed operation.

  As a result, in an open system such as a touch-and-go system such as an entrance / exit gate and a ticket gate, the operation range can be increased by identifying the IC card at a longer distance and expanding the operable range. Get faster. In the touch and go system and the like, the IC card moves from a weak magnetic field to a strong magnetic field as the IC card reader / writer is approached, so that a faster processing operation can be performed and the sensation speed can be improved. it can.

  In a close contact type system such as an authentication system, if the output from the IC card reader / writer is set high, processing can be performed at high speed.

  Furthermore, since the operation speed of the IC card can be changed without requiring external control, an increase in processing time due to communication can be reduced, and processing of an external application can be simplified. .

  Embodiments of a non-contact type IC card according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram showing a main configuration of a contactless IC card according to an embodiment of the present invention.

  As shown in FIG. 1, the non-contact type IC card 10 includes an antenna means 1 such as a loop antenna, a tuning capacitor 2, a rectifier circuit 3, a power supply circuit 4, a frequency divider circuit 5, and a power detection circuit 6. , A clock selection circuit 7 and a CPU (Central Processing Unit) / memory unit 8, which communicates with an external device using a magnetic field using the antenna means 1 and acquires operating power for operating the integrated circuit. . By the power detection circuit 6 and the clock selection circuit 7, the operation clock in the integrated circuit is determined according to the relative magnitude relationship between the received power level received from the communication radio magnetic field and the power consumption level consumed in the integrated circuit. A clock control unit 9 (clock control circuit) is configured as clock control means for controlling the frequency. Here, the integrated circuit is an IC chip and may be the CPU / memory unit 8, but more precisely, the power detection circuit 6, the clock selection circuit 7 and the CPU / memory supplied by the power supply circuit 4. All circuit units including the unit 8 may be used.

  The antenna means 1 receives a surrounding magnetic field and generates a voltage or a current. Specifically, the antenna means 1 is electromagnetically coupled with an external device such as an IC card reader / writer to receive power from the carrier, and receives magnetic field between the antenna means 1 and the IC card reader / writer. Communication takes place. That is, the antenna means 1 generates an AC voltage at both ends in proportion to the AC magnetic field received.

  The tuning capacitor 2 is connected in parallel with the antenna means 1 and constitutes a parallel resonance circuit together with the antenna means 1 and the subsequent load after the rectifier circuit 3. That is, the tuning capacitor 2 is set so that the antenna means 1 can receive power efficiently. Usually, this set value is set to coincide with the carrier frequency as the parallel resonance frequency of the LCR. Also, in applications such as an authentication system that is in close contact with an IC card reader / writer, it may be set in consideration of impedance conversion of the transmission path.

  The rectifier circuit 3 is connected in parallel with the antenna means 1 and the tuning capacitor 2. In this rectifier circuit 3, the AC voltage generated at both ends of the antenna means 1 is converted into a DC voltage, and the converted DC voltage is input to the power supply circuit 4.

  The output from the rectifier circuit 3 is proportional to the magnetic field strength received by the IC card, and shows a high voltage value when the magnetic field strength is large and a low voltage value when the magnetic field strength is small. The output from the rectifier circuit 3 is inversely proportional to the power consumption of the IC card (LSI) after the power supply circuit in the next stage, and shows a small voltage value when the current consumption is large, and large when the current consumption is small. Indicates the voltage value.

  In FIG. 1, the rectifier circuit 3 is constituted by a full-wave rectifier circuit having four diodes and one capacitor. However, the present invention is not limited to this, and other rectifier circuits such as a half-wave rectifier circuit may be used. Further, depending on the configuration of the power supply circuit 4, the output from the rectifier circuit 3 has a constant voltage value. However, these operations are for a series rectifier circuit.

  Here, the output from the power supply circuit (regulator) 4 is used as the input to the power detection circuit 6. However, the output from the rectifier circuit 3 is not limited to this. It can also be used as an input to the power detection circuit 6 for determining whether the power consumption inside the integrated circuit is large or small. The power supply circuit (regulator) 4 is provided to supply a stabilized DC voltage to the entire IC card.

  Hereinafter, the configuration of the power supply circuit (regulator) 4 will be described in detail with reference to FIGS.

  FIG. 2 is a circuit diagram showing a main configuration of a series type power supply circuit as an example of the power supply circuit 4 of FIG.

  As shown in FIG. 2, the series type power supply circuit 4A includes a field effect transistor (FET) 41, an operation (OP) amplifier 42, resistors 43a and 43b, and a capacitor 44. The desired DC voltage (output power supply voltage) stabilized by controlling the current value for conducting the current is supplied.

  The FET 41 controls the current input from the rectifier circuit 3 to the input unit (input) according to the output voltage (power supply control potential) from the OP amplifier 42.

  The output terminal of the OP amplifier 42 is connected to the gate of the FET 41, the divided voltage of the resistors 43a and 43b is input to one of the two input terminals, and a bias voltage of a predetermined voltage is input to the other.

  The series circuit of the resistors 43a and 43b is provided between the output side from the FET 41 and the ground voltage. The voltage dividing ratio of the resistors 43a and 43b is the voltage at the connection point of the resistors 43a and 43b (the resistors 43a and 43b) when the power supply voltage from the output unit (out put) of the power supply circuit 4A is a predetermined power supply voltage. 43b) and the input bias voltage are set to coincide with each other.

  The capacitor 44 is a capacitor for smoothing the power supply voltage from the output part (out put) of the power supply circuit 4A, but may not be provided depending on the specifications of the power supply circuit.

  FIG. 3 is a circuit diagram showing a main configuration of a shunt-type power supply circuit as another example of the power supply circuit 4 of FIG.

  As shown in FIG. 3, the shunt-type power supply circuit 4B has an FET 45, an OP amplifier 46, resistors 47a and 47b, and a capacitor 48, and is stabilized by controlling the shunting of the input current via the FET 45. A desired DC voltage (output power supply voltage) is supplied.

  The FET 45 is provided between the input unit (input) and the ground unit (ground voltage), and an output power supply voltage that is defined in advance by the current value input from the rectifier circuit 3 to the input unit (input) is obtained. As described above, the value of the current flowing from the input unit to the ground unit is controlled in accordance with the output voltage (power supply control potential) from the OP amplifier 42.

  The output terminal of the OP amplifier 46 is connected to the gate of the FET 45, the divided voltage of the resistors 47a and 47b is input to one of the two input terminals, and a bias voltage of a predetermined voltage is input to the other.

  The series circuit of the resistors 43a and 43b is provided between the input unit (input) and the ground unit. The voltage dividing ratio of these resistors 43a and 43b is the voltage at the connection point of the resistors 47a and 47b (resistors 47a and 47b) when the power supply voltage from the output section (out put) of the power supply circuit 4B is a predetermined power supply voltage. 47b) and the input bias voltage are set to coincide with each other.

  The capacitor 48 is a capacitor for smoothing the power supply voltage from the output part (out put) of the power supply circuit 4B, but may not be provided depending on the specifications of the power supply circuit.

  In the power supply circuit 4A shown in FIG. 2 and the power supply circuit 4B shown in FIG. 3, the control state is known by the output voltages from the OP amplifiers 42 and 46. Therefore, by inputting the output voltage to the power detection circuit 6, the magnetic field It is possible to detect the power consumption level of the integrated circuit with respect to the received power level received from.

  The power supply circuits 4A and 4B can be controlled by the output voltages from the OP amplifiers 42 and 46, respectively, to obtain a stabilized output power supply voltage, and the input to the power detection circuit 6 is input to the integrated circuit. Any portion may be used as long as it can detect the current consumption state, and for example, a power supply circuit using a Zener diode may be used.

  Returning to FIG. 1, the frequency dividing circuit 5 receives the basic clock signal, divides this frequency to generate a clock signal having a frequency lower than the basic clock frequency, and generates the generated clock signal. The clock selection circuit 7 is supplied. The basic clock number may be extracted from a carrier supplied for power transmission from the IC card reader / writer, or may be supplied from an oscillator or the like mounted inside the IC card. Further, a clock signal faster than a reference clock (an oscillator or a carrier frequency or a frequency obtained by dividing the frequency) may be generated by a PLL (phase locked loop) or the like, and this may be used as a basic clock signal.

  FIG. 4 is a circuit diagram showing an example of the frequency dividing circuit 5 of FIG.

  As shown in FIG. 4, the frequency dividing circuit 5 includes n−1 D-type flip-flops (DFF) 1 to N−1. This N is a natural number. Each DFF outputs a clock signal having a frequency divided by 2 times, 4 times, 8 times,... With respect to the basic clock signal. The basic clock signal and these clock signals are an operation clock signal 1, an operation clock signal 2,..., An operation clock signal n of the CPU / memory unit 8 of the integrated circuit. The magnitude of n is determined by how many stages the operation clock frequency is switched. This n is a natural number.

  In FIG. 4, the Q output of each DFF is output as an operation clock signal of the CPU / memory unit 8 of the integrated circuit, and the output QB is input to the data input terminal D and input to the clock input terminal CK of the subsequent DFF. Thus, a ripple carry type frequency divider is configured, but a synchronous frequency divider may be used. Further, although the clock signal has frequency division frequencies of 2, 4, 8 times,... Of the basic clock signal, an intermediate frequency division frequency may be created as necessary. Further, the duty is not limited to 50:50.

  Next, the power detection circuit 6 shown in FIG. 1 determines whether the power consumption consumed by the integrated circuit is larger or smaller than the magnetic field strength received by the IC card. In order to detect the current power consumption state of the integrated circuit, as described above, the output values of the OP amplifiers 42 and 46 in the power supply circuits 4A and 4B shown in FIGS. 2 and 3 can be used. is there.

  In the power supply circuit 4A shown in FIG. 2, when the power consumed in the integrated circuit increases, the power supply voltage from the output unit (out put) tends to decrease. When the power supply voltage from the output unit (out put) is lowered, the potential at the resistance connection point (one input voltage of the OP amplifier 42) whose potential is determined by the voltage dividing ratio of the resistors 43a and 43b is also lowered. Therefore, the OP amplifier 42 is controlled to increase the potential at the resistance connection point (one input voltage of the OP amplifier 42), and the drain current of the FET 41 is increased so that the power supply from the output unit (out put) is increased. The power supply circuit 4A performs a stabilizing operation so that the voltage is raised and restored.

  On the other hand, when the power consumed in the integrated circuit decreases, the power supply voltage from the output unit (out put) increases. When the power supply voltage from the output unit (out put) increases, the potential at the connection point (one input terminal of the OP amplifier 42) where the potential is determined by the voltage dividing ratio of the resistors 43a and 43b also increases. Therefore, the power supply circuit 4A operates such that the output voltage is lowered by the OP amplifier 42, the drain current of the FET 41 is reduced, and the power supply voltage from the output unit (out put) is lowered and restored.

  Also in the power supply circuit 4B shown in FIG. 3, when the power consumed in the integrated circuit increases, the power supply voltage from the output unit (out put) tends to decrease. When the power supply voltage from the output unit (out put) is lowered, the potential at the connection point (one input terminal of the OP amplifier 46) where the potential is determined by the voltage dividing ratio of the resistors 47a and 47b is also lowered. For this reason, the power supply circuit 4B operates so that the output voltage is lowered by the OP amplifier 46, the drain current of the FET 45 is reduced, and the power supply voltage from the output unit (out put) is lowered and restored.

  On the other hand, when the power consumed in the integrated circuit decreases, the power supply voltage from the output unit (out put) increases. When the power supply voltage from the output unit (out put) increases, the potential at the connection point (one input terminal of the OP amplifier 46) where the potential is determined by the voltage dividing ratio of the resistors 47a and 47b also increases. As a result, the output voltage is increased by the OP amplifier 46, the drain current of the FET 45 is increased, and the power supply circuit 4B operates so that the power supply voltage from the output unit (out put) is increased and restored.

  Thus, the output voltage from the OP amplifier 46 can be used to detect the state of the power consumption level of the integrated circuit with respect to the power reception level received by the magnetic field.

  Next, in the voltage detection circuit 6, the OP amplifier output voltage is detected from the power supply circuit 4A or 4B, and this is used as a detection voltage and compared with a reference voltage set in advance by a comparator (comparator) or the like, thereby generating a magnetic field. Thus, it can be determined whether the power consumption level of the integrated circuit with respect to the received power level received is high or low.

  When the voltage detection circuit 6 determines that the power consumption of the integrated circuit is large, the clock selection circuit 7 shown in FIG. 1 is controlled to lower the operation clock frequency in order to reduce the power consumption of the integrated circuit. A signal is supplied. Further, when it is determined that the IC card 10 receives sufficient magnetic field strength and the power consumption used by the integrated circuit may be increased, the clock selection circuit 7 is set so as to increase the operation clock frequency. Is supplied with a control signal.

  The voltage detection circuit 6 compares, for example, a reference voltage value and a value (detection voltage value) supplied from the power supply circuit 4 by a comparator, sets the determination result to “0” and “1”, and sets the control signal to the clock selection circuit. 7 is supplied. A reference voltage value used as a determination criterion can be defined at the time of design. The reference voltage value may be fixed as hardware, or can be variably controlled by software.

  Next, in the clock selection circuit 7, a plurality of clock signals generated by the frequency divider 5 are selected according to the control signal from the power detection circuit 6 and are output as operation clock signals of the CPU / memory unit 8.

  FIG. 5A is a circuit diagram illustrating an example of the power detection circuit 6 in FIG. 1, and FIG. 5B is a circuit diagram illustrating an example of the clock selection circuit 7 in FIG. In FIG. 5, the clock control unit 9 including the power detection circuit 6 and the clock selection circuit 7 is configured by hardware, and the operation clock frequency of the CPU / memory unit 8 configuring the integrated circuit is controlled by hardware. An example of the case is shown.

  As shown in FIG. 5A, the voltage detection circuit 6 includes n (n is a natural number) comparators 1 to n (COM1 to COMn) and n AND circuits 6-1 to 6-n (AND6). 1-AND6-n).

  Here, it is assumed that the reference voltages input to the comparators 1 to n are set to Vn <... <V2 <V1.

  Each of the comparators 1 to n receives the OP amplifier output voltage from the power supply circuit 4 as the detection voltage Vd. Here, it is assumed that the reference voltages V1 to Vn input to the comparators 1 to n are set to Vn <... <V2 <V1.

  The AND circuit 6-1 receives the comparison voltage 1 output from the comparator 1 as it is, and inverts the comparison voltages 2 to n output from the comparators 2 to n. Further, the comparison voltages 1 and 2 output from the comparators 1 and 2 are input as they are to the AND circuit 6-2, and the comparison voltages 3 to n output from the comparators 3 to n are inverted and input. . Further, the comparison voltages 1 to n output from the comparators 1 to n are input to the AND circuit 6-n as they are. Here, the clock selection signals output from the AND circuits 6-1 to 6-n are such that n is the operation clock frequency of the integrated circuit so that 1 is the lowest (lowest speed) operation clock frequency of the integrated circuit. It is set to be the highest (highest speed).

  The voltage detection circuit 6 receives the output voltage from the OP amplifier 42 as the detection voltage V in the power supply circuit 4A shown in FIG. 2, and Vk <V <Vk-1 (3 <k <n-1). Think about the case. Since the detection voltage V <the reference voltage Vk−1 <... <V1, the outputs of the comparators 1 to n are detected as “H” from the comparison voltage 1 to the comparison voltage Vk−1. As a result, the clock selection signal k-1 is enabled in the AND circuits 6-1 to 6-n.

  Here, when the current consumption of the CPU / memory unit 8 constituting the integrated circuit is increased by a certain command, the output voltage from the OP amplifier 42 in the power supply circuit 4A shown in FIG. Assuming that the value V of the output voltage is increased by one step, Vk-1 <V <Vk-2, and the outputs of the comparators 1 to n detect that the comparison voltage 1 to the comparison voltage Vk-2 are "H". Is done. As a result, in the AND circuits 6-1 to 6-n, the clock selection signal k-2 is enabled and operates to lower the operation clock frequency of the CPU / memory unit 8 of the integrated circuit.

  On the other hand, when the current consumption of the CPU / memory unit 8 of the integrated circuit decreases, as described above, the output voltage from the OP amplifier 42 in the power supply circuit 4A shown in FIG. Assuming that the value V of the output voltage is lowered by one step, Vk + 1 <V <Vk, and the outputs of the comparators 1 to n are detected as the comparison voltage 1 to the comparison voltage Vk being “H”. As a result, in the AND circuits 6-1 to 6-n, the clock selection signal k is enabled, and the operation clock frequency of the CPU / memory unit 8 of the integrated circuit is increased.

  On the other hand, as shown in FIG. 5B, the clock selection circuit 7 has n AND circuits 7-1 to 7-n and one output circuit OUT. Each of the AND circuits 7-1 to 7-n receives clock selection signals 1 to n output from the voltage detection circuit 6, and receives clock signals 1 to n from the frequency dividing circuit 5, respectively. ing. The output circuit OUT receives clock signals output from the AND circuits 7-1 to 7-n. As a result, a clock signal is output from the AND circuit in which the clock selection signal is enabled, and the output clock signal is supplied as an operation clock signal from the output circuit OUT to the CPU / memory unit 8 of the integrated circuit.

  In this way, the power detection circuit 6 and the clock selection circuit 7 can select an operation clock frequency corresponding to the received power level.

  In FIG. 5, the description has been made based on the positive logic. However, the clock control unit 9 detects the current consumption and power consumption with respect to the received power, and selects an operation clock signal to the integrated circuit (CPU / memory unit 8). As long as it is possible, the input of a comparator or the like may be reversed, or the logic may be inverted. Further, when the IC card 10 of the present invention is actually used, it is necessary to synchronize the clock selection signal because of a hazard problem. For example, a method of taking a clock selection signal into the D-type flip-flop at the falling edge of the clock signal currently used can be considered. In addition to this, switching is allowed only when the counter value used in the frequency divider circuit 5 is “0”, the clock selection signal is not changed for a certain period of time, and the detected value is averaged to some extent. It may be made to judge as. At this time, the basic clock signal is used for those that require absolute time, such as a clock signal related to a timer or a communication signal.

  A slot for using the non-contact type IC card 10 of the present embodiment configured as described above in a state where the IC card 10 and the IC card reader / writer are fixed with a gap of several mm as in a personal authentication system, for example. When used in an in-type system, a high-speed clock signal is automatically selected in the IC card 10 by setting a high output level from the IC card reader / writer. Even complicated processing requiring power can be executed at high speed.

  In addition, the distance between the IC card 10 and the IC card reader / writer is relatively large, such as a ticket gate at a station or an entrance / exit gate to a specific room. A case of using an open type system approaching a writer will be described with reference to FIG.

  In FIG. 6, an antenna surface 20 is provided in an IC card reader / writer as an IC card reader / writer means used as a gate terminal. Here, a case is considered in which the non-contact type IC card 10 of the present embodiment and the conventional non-contact type IC card 100 are carried from the point D reaching the antenna surface 20 toward the point A by the user's hand.

  In the conventional non-contact type IC card 100, the operation clock frequency of the integrated circuit is fixed. It is assumed that the operation clock frequency is fHz, the magnetic field is distributed radially from the antenna surface 20 of the IC card reader / writer, and the operation limit point at the operation clock frequency is C point. Here, in order to simplify the explanation, it is assumed that AB, BC, and CD are equidistant and move in one second each. The conventional non-contact type IC card 100 operates in AC, and the number of operation steps is 2f.

  On the other hand, in the contactless IC card 10 of the present embodiment, the operation clock frequency is changed according to the power consumption level of the integrated circuit with respect to the power reception voltage level received by the magnetic field. By reducing the power consumption, it is possible to operate even between CD. Assuming that the operation clock frequency is set to (1 / n) fHz, the number of operation steps is (1 / n) f. Further, assuming that the operation clock frequency is set to fHz between B and C, the number of operation steps is f. Further, if sufficient power is supplied, the operation clock frequency increases. Therefore, assuming that the operation clock frequency is set to mfHz between A and B, the number of operation steps is mf steps. Therefore, the number of steps that can be processed between A and D is (1 / n + 1 + m) f steps. Since n and m are both 1 or more, the number of steps is (1 / n + 1 + m) f> 2f in the non-contact type IC card 10 of the present embodiment, compared to the number of steps 2 f in the conventional non-contact type IC card 100. Thus, more processing can be performed at the same time. Moreover, when performing the same process, it can process in a short time. Furthermore, it is possible to expand the operation range by the CD section.

  As described above, according to the present embodiment, the power consumption level of the integrated circuit with respect to the received power level by the power detection circuit 6 in the non-contact type IC card 10 that performs communication by the magnetic field using the antenna unit 1 and acquires the operating power. When the power consumption is large, the clock selection circuit 7 increases the operation clock frequency, and when the power consumption is small, the operation clock frequency is decreased to optimize the received power and the current consumption. In a close contact system capable of receiving a strong magnetic field, the clock frequency is increased to increase the processing speed. In an open type system in which the received power goes from a weak state to a strong state, the power consumption is lowered by a weak magnetic field, the operation time is extended in a wider range, and the processing speed is shortened by a strong magnetic field to shorten the sensory time. As a result, the non-contact type IC card 10 can be operated at a higher magnetic field strength and operated at a lower magnetic field strength without external control.

  Further, if the non-contact type IC card 10 of the present embodiment is used in an open type system such as a touch and go system such as an entrance / exit gate or a ticket gate, the operation start time is shortened, and the IC card reader / High-speed operation is possible as the writer is approached, so that the sensation speed can be improved.

  Although not described in detail in the above embodiment, in the non-contact type IC card 10, the control means (CPU) controls the surrounding wireless magnetic field based on a control program recorded on a readable recording medium such as a ROM. A determination step for determining a relative magnitude relationship between the received power level received from the power consumption level consumed in the integrated circuit (IC chip), and the power consumption level is predetermined based on the determination result of the magnitude relationship. The software configuration of the present invention is also possible when executing the clock frequency control step for variably controlling the operation clock frequency inside the integrated circuit so as to fall within the range.

  In the present embodiment, the case where the present invention is applied to a non-contact type IC card has been described. However, the present invention is not limited to this, and the present invention can also be applied to an electronic information device and a portable electronic information device. This electronic information device can also be used for in-vehicle electronic information devices. Moreover, as a portable electronic information device, a person can carry it by incorporating it into a portable item such as a name tag, a badge, or a bracelet, and it can be used for opening and closing a gate device through an authentication system. As described above, as in the case of the non-contact type IC card, an open type system using the electronic information device and the portable electronic information device of the present invention can be configured.

  In addition, as mentioned above, although this invention was illustrated using the said preferable embodiment of this invention, this invention should not be limited and limited to this said embodiment. It is understood that the scope of the present invention should be construed only by the claims. It is understood that those skilled in the art can implement an equivalent range based on the description of the present invention and the common general technical knowledge from the description of the specific preferred embodiments described above. Patents, patent applications, and documents cited herein should be incorporated by reference in their entirety, as if the contents themselves were specifically described herein. Understood.

  For example, in the field of contactless IC cards that acquire operating power for operating an integrated circuit by communicating with an external device such as an IC card reader / writer by a magnetic field, when the received power level is insufficient, the operating clock of the integrated circuit By reducing the frequency, the power consumption can be reduced and the operable area from the IC card reader / writer can be expanded. Further, if the received power level is sufficient, high-speed operation can be performed by increasing the operation clock frequency of the integrated circuit. In addition, the non-contact IC card itself can change the operating clock frequency without being controlled from the outside, so processing can be performed at a higher speed without causing processing to stop due to communication with external devices. It becomes.

  Therefore, in a system such as an entrance / exit gate, discrimination from a longer distance becomes possible. In applications where power consumption is large, such as an authentication system, high-speed processing is possible by increasing the output of the IC card reader / writer. Furthermore, in an open type system such as a touch-and-go system such as an entrance / exit gate and a ticket gate, the operation start time becomes early, and the high speed operation becomes possible as the IC card reader / writer is approached. Speed can be improved. Thereby, non-contact type IC cards can be used for a wide range of applications from an open type system such as an entrance / exit gate and a ticket gate to a close contact type system such as an authentication system, thereby contributing to the spread of these systems.

It is a block diagram which shows the principal part structure of the non-contact-type IC card which is one Embodiment of this invention. FIG. 2 is a circuit diagram illustrating a main configuration of a series power supply circuit as an example of the power supply circuit of FIG. 1. FIG. 3 is a circuit diagram showing a main configuration of a shunt type power supply circuit as another example of the power supply circuit of FIG. 1. FIG. 2 is a circuit diagram illustrating an example of a frequency dividing circuit in FIG. 1. (A) is a circuit diagram showing an example of the power detection circuit of FIG. 1, (b) is a circuit diagram showing an example of the clock selection circuit of FIG. It is a schematic diagram for demonstrating the difference of each operation | movement about the case where the non-contact-type IC card of this embodiment and the conventional non-contact-type IC card are used for an open type system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Antenna means 2 Tuning capacitor 3 Rectifier circuit 4, 4A, 4B Power supply circuit 41, 45 FET (transistor means)
42,46 OP amplifier (amplification means)
5 Dividing circuit (dividing means)
6 Power detection circuit (Power detection means)
COM1n comparator (comparison means)
AND6-1 to 6-n, AND7-1 to 7-n AND circuit (logic means)
7 Clock selection circuit (clock selection means)
8 CPU and memory (integrated circuit; IC chip)
9 Clock controller (clock control means)
10 Non-contact type IC card

Claims (22)

An antenna means for generating a voltage or a current by receiving a surrounding radio magnetic field and an integrated circuit, and using the antenna means to obtain operating power for operating the integrated circuit and between external devices In a non-contact type IC card that enables communication,
The power consumption level is a predetermined range including the received power level as a maximum value in accordance with a relative magnitude relationship between the received power level received from the surrounding wireless magnetic field and the consumed power level consumed in the integrated circuit. A non-contact type IC card having clock control means for controlling an operating clock frequency inside the integrated circuit so as to be inside.   The contactless IC card according to claim 1, wherein the clock control unit controls an operation clock frequency inside the integrated circuit so that the power consumption level matches the received power level. The clock control means includes
When the power consumption level consumed inside the integrated circuit is smaller than the predetermined range with respect to the received power level, the operation clock frequency inside the integrated circuit is increased, and when the power consumption level is larger than the predetermined range, the integration is performed. The non-contact type IC card according to claim 1, wherein the non-contact type IC card is controlled to lower an operation clock frequency inside the circuit.   The non-contact type IC card according to claim 1, wherein the clock control unit selects one of a plurality of clock signals having different frequencies. The clock control means is executed based on a control program.
Determining means for determining the relative magnitude relationship;
4. A clock frequency control means for controlling an operation clock frequency inside the integrated circuit based on a result of determination of the magnitude relationship so that the power consumption level falls within the predetermined range. Non-contact type IC card.   The non-contact type IC card according to claim 1, wherein the clock control unit includes a clock control circuit that controls an operation clock frequency of the integrated circuit. The clock control circuit includes:
Power detection that outputs a control signal according to when the power consumption level consumed inside the integrated circuit is smaller than the predetermined range and when the power consumption level is larger than the predetermined range with respect to the received power level Circuit,
In response to the control signal, when the power consumption level consumed inside the integrated circuit is smaller than the predetermined range with respect to the received power level, the operation clock frequency inside the integrated circuit is increased, and the power consumption level is 7. The non-contact type IC card according to claim 6, further comprising: a clock selection circuit that selects one of a plurality of clock signals so as to lower an operation clock frequency inside the integrated circuit when larger than a predetermined range. A tuning capacitor connected in parallel to the antenna means to form a parallel resonant circuit;
A rectifier circuit connected to both ends of the antenna means for converting the AC voltage received by the antenna means into a DC voltage;
A power supply circuit connected to an output section of the rectifier circuit to stabilize a power supply current and supplying the integrated circuit;
An input basic clock signal and a frequency dividing circuit that outputs a clock signal having a plurality of frequencies obtained by dividing the input basic clock signal;
The power detection circuit compares a power supply control potential in the power supply circuit with a preset reference voltage to determine a relative magnitude relationship between the received power level and the power consumption level;
The contactless IC according to claim 7, wherein the clock selection circuit selects one of a plurality of clock signals output from the frequency divider circuit based on the magnitude relation determination result and supplies the selected clock signal to the integrated circuit. card.   9. The non-contact type IC card according to claim 8, wherein the power supply circuit is a series type power supply circuit or a shunt type power supply circuit in which a power supply current is output-controlled according to the power supply control potential.   The non-contact type IC card according to claim 8, wherein a plurality of the reference voltages are set.   The non-contact type IC card according to claim 8 or 10, wherein the reference voltage is switchable.   9. The non-contact type IC card according to claim 1, wherein the antenna means is a loop antenna.   The non-contact type IC card according to claim 1, wherein the integrated circuit is an IC chip.   An IC that performs at least one of data reading and data writing in a non-contact manner by radio field communication with the non-contact type IC card according to claim 1 and the approached non-contact type IC card. An open system having a card reader / writer means. An antenna means for generating a voltage or a current by receiving a surrounding radio magnetic field and an integrated circuit, and using the antenna means to obtain operating power for operating the integrated circuit and between external devices In electronic information equipment that enables communication,
The power consumption level is a predetermined range including the received power level as a maximum value in accordance with a relative magnitude relationship between the received power level received from the surrounding wireless magnetic field and the consumed power level consumed in the integrated circuit. Electronic information equipment having clock control means for controlling the operating clock frequency inside the integrated circuit so as to be inside.   16. An open circuit comprising: the electronic information device according to claim 15; and reader / writer means for performing at least one of data reading and data writing in a non-contact manner by wireless magnetic field communication with the electronic information device brought close to the electronic information device. Mold system. An antenna means for generating a voltage or a current by receiving a surrounding radio magnetic field and an integrated circuit, and using the antenna means to obtain operating power for operating the integrated circuit and between external devices In portable electronic information devices that enable communication,
The power consumption level is a predetermined range including the received power level as a maximum value according to the relative magnitude relationship between the received power level received from the surrounding wireless magnetic field and the consumed power level consumed in the integrated circuit. A portable electronic information device having clock control means for controlling an operation clock frequency inside an integrated circuit so as to be inside.   18. A portable electronic information device according to claim 17, and reader / writer means for performing at least one of data reading and data writing in a non-contact manner by communication using a wireless magnetic field with respect to the portable electronic information device brought close to the portable electronic information device Open system with. It is a power consumption control method of the non-contact type IC card according to claim 1,
A determination step of determining a relative magnitude relationship between a received power level received from the surrounding wireless magnetic field and a power consumption level consumed inside the integrated circuit;
A power consumption control method comprising: a clock frequency control step of variably controlling an operation clock frequency inside the integrated circuit so that the power consumption level falls within the predetermined range based on the determination result of the magnitude relationship. A power consumption control method for a portable electronic information device according to claim 17,
A determination step of determining a relative magnitude relationship between a received power level received from the surrounding wireless magnetic field and a power consumption level consumed inside the integrated circuit;
A power consumption control method comprising: a clock frequency control step of variably controlling an operation clock frequency inside the integrated circuit so that the power consumption level falls within the predetermined range based on the determination result of the magnitude relationship.   A control program for causing a computer to execute each step of the power consumption control method according to claim 19 or 20. A computer-readable recording medium on which the control program according to claim 21 is recorded.

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