JPH11120306A - Data access method and device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To enable communication even if there is a switching noise source. In a data access method and apparatus in which a power supply Vcc and a command A are transmitted / received by an electromagnetic induction coupling method utilizing mutual inductive action of coils 33, 41, 71, when a command A is transmitted, a predetermined value is transmitted. Is transmitted (610), the reception of response data is refrained for a predetermined period (210, B, 460), and the response data is returned (610) to command A and received with a delay. (D, 460). Since the switching noise is suppressed by transmitting the dummy response, the shunt switching regulator 8
00 can also be used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data access method which does not require contact by an electromagnetic inductive coupling method, and a data reading device and a data storage device for performing the data access. More specifically, the present invention focuses on a power supply circuit in a data storage device such as an IC card or a data carrier that communicates with a data reading device such as a reader / writer and receives power necessary for operation of a memory and a control circuit. , And a series of improvements associated therewith.

[0002]

2. Description of the Related Art A conventional data access system whose block diagram is shown in FIG. 3 is composed of a reader / writer 10 (data reading device), which is often installed and used, and a coin type or a card type for easy carrying. Data carrier 50 (data storage body).
When 0 is brought close to the reader / writer 10, the reader / writer 10 reads necessary data from the data carrier 50 by performing communication based on electromagnetic induction coupling even in a non-contact state. When the data carrier 50 approaches the reader / writer 10 so that communication is possible, the data carrier 50 is also supplied with energy by electromagnetic induction coupling of communication.

More specifically, a reader / writer 10 includes a microprocessor 2 for performing overall control and data arithmetic processing.
0, a transmitting unit 30 for transmitting the command signal A on a carrier wave of the frequency f1, and a receiving unit 40 for receiving a signal carried on the frequency f2. The microprocessor 20 has a command sending routine 21, an application routine 22, a response receiving routine 23, and the like installed therein.

The command transmission routine 21 generates a command for instructing the data carrier 50 to read or write data, and includes a command signal A for transmitting the command to the transmission unit 30. . The application routine 22 performs processing corresponding to various applications. The application routine 22 requests the command transmission routine 21 to read and write data necessary for the processing, and receives such data from the response reception routine 23. Has become. The response receiving routine 23 performs a process of receiving the restored data E of the response data returned from the data carrier 50 via the receiving unit 40.

The transmitting section 30 has a modulation circuit 31 for modulating the carrier wave of the frequency f1 with the command signal A, and has an amplifier 32 in order to transmit a command using the mutual induction action of the coils. A modulated signal is amplified by the amplifier 32 and a series resonance circuit of the transmission coil 33 (electromagnetic induction coupler) is provided. When no command is included in the command signal A, the frequency f
By transmitting one carrier wave without any modulation, the power which is the operating energy of the data carrier 50 is also supplied with the help of the mutual inductive action of the coils used for the command transmission.

[0006] The receiving unit 40 receives the response data returned by utilizing the mutual induction action of the coils.
It has a parallel resonance circuit of a receiving coil 41 (electromagnetic induction coupler). With this, an effective band component centered on the frequency f2 is extracted from a signal obtained by electromagnetic conversion by a band-pass filter 42, and this is amplified by an amplifier 43. To generate a reception signal C. Further, the receiving unit 40 extracts a clock from the received signal C by the clock extraction circuit 44, generates a detection signal D by the synchronous detection circuit 45 using the clock, and binarizes the detection signal D by the buffer 46. Thus, the restoration data E that can be digitally processed is generated. Note that the frequency f2 of the return carrier is different from the frequency f1 such as 1/2 or 1/4 times for discrimination from the frequency f1 of the transmission carrier.

On the other hand, the data carrier 50 is provided with a logic unit 60 for performing overall control and data storage and the like, and a transmission coil 33 and a reception coil 41 of the reader / writer 10 utilizing electromagnetic induction by utilizing mutual induction of the coils. A transmitting / receiving coil 71 (electromagnetic induction coupler) for coupling, and power supply units 72, 80, 7 for obtaining operating power of the logic unit 60 from induced electromotive force induced in the transmitting / receiving coil 71 by the electromagnetic induction coupling.
3 is provided.

[0008] The logic unit 60 receives the power supply voltage V from the power supply unit.
This is a CMOS-based logic circuit that operates by being supplied with power of cc, and includes a transmission unit 61, a control unit 63, a memory 64, a reception unit 65, and the like. Note that the memory 64
Is composed of a rewritable nonvolatile memory such as an EEPROM, and may be an IC separate from the logic unit 60. The receiving unit 65 inputs a reception signal via a receiver 66 connected to one end of the transmission / reception coil 71 in order to restore the command from the reader / writer 10 received by the transmission / reception coil 71, and converts the component centered on the frequency f1 therefrom. The command is extracted and subjected to a predetermined demodulation process to obtain a command. The restored command is sent to the control unit 63.

If the command is a read command, the control unit 63 reads data from the corresponding address of the memory 64 specified by the command, and requests the logic unit 60 to return the data as response data. If the command is a write command, the data is written to the corresponding address of the memory 64 designated by the command, and the logic unit 60 is requested to return response data indicating completion of the writing. The transmitting unit 61 generates a transmission signal by performing a predetermined modulation process such as DPSK or ASK on the carrier wave of the frequency f2 with the response data in order to return the response data via the transmission / reception coil 71. One end of the transmission / reception coil 71 is driven via the driver 62.

The power supply unit of the data carrier 50 stores a rectifier 72 for receiving and rectifying the alternating current induced in the transmitting / receiving coil 71, a series regulator 80 for stabilizing the voltage of the rectified current, and storing the output current. And a capacitor 73 sent to the logic unit 60. The series regulator 80 is a logic unit 6
Logic unit 60 so that overvoltage is not applied to 0
In order to maintain the power supply voltage Vcc to a predetermined constant voltage such as 3 V or 5 V, a pass transistor 82 inserted between the rectifier 72 and the capacitor 73 in the line of the power supply voltage Vcc, and the voltage dividing of the power supply voltage Vcc And an operational amplifier 81 for controlling the pass transistor 82 so that there is no difference between the reference voltage and the reference voltage.

When the data access system having such a configuration is used, the reader / writer 10 and the data carrier 50 operate as follows. 4A and 4B show signal waveform examples during operation, wherein FIG. 4A shows the waveform of the command signal A, FIG. 4B shows the waveform of the reception signal C, FIG. 4C shows the waveform of the detection signal D, and FIG.
Shows the waveform of the restored data E.

When the data carrier 50 is brought close to the reader / writer 10 while the reader / writer 10 is transmitting a carrier wave of the frequency f1, an induced current flows through the transmitting / receiving coil 71 in the data carrier 50, and the power supply unit, that is, the rectifier 72 The power of the power supply voltage Vcc is generated from the induced current by the series regulator 80 and the capacitor 73,
The logic unit 60 and the entire data carrier 50 are now operable. In this way, power is supplied from the reader / writer 10 to the data carrier 50 by the electromagnetic induction coupling method using the mutual induction action of the coils. this is,
The following commands and the like can be transmitted or received continuously or intermittently in the interval.

In this state, if a predetermined initial communication or the like has been performed, the communication is completed, and then a data read command A1 is issued from the command transmission routine 21 of the reader / writer 10 (FIG. 4).
(See (a)), which is transmitted to the data carrier 50 via the transmission unit 30. In the data carrier 50, the command is received by the transmission / reception coil 71 and the reception unit 65, and in accordance with the command, the corresponding data is read from the memory 64 by the control unit 63, and the transmission unit 61 and the transmission / reception coil 7 are received.
The response data is sent back to the reader / writer 10 via 1. Since these processes are promptly performed by the data carrier 50, in the reader / writer 10, a reception waveform C1 of the response data is obtained by the reception unit 40 immediately after the transmission of the command A1 (see FIG. 4B). Further, the detection waveform D1 of the response data (see FIG. 4C) and the restored data E1 are obtained by the processing of the receiving unit 40 (see FIG. 4D).

When a data write command A2 is issued from the reader / writer 10 (see FIG. 4 (a)), similarly, response data indicating completion of writing is returned from the data carrier 50. C2
(See FIG. 4B), a detection waveform D2 (see FIG. 4C), and restored data E2 (see FIG. 4D). As soon as the command is sent,
The return of the response data to the command and the reception thereof are performed.

The power supply circuit shown in FIG. 5 is a shunt regulator that can be used for the data carrier 50 instead of the series regulator 80 described above. FIG.
The Zener shunt regulator 83 shown in FIG. 9 is a Zener diode connected in parallel with the capacitor 73, and the bipolar shunt regulator 84 shown in FIG. 9B uses a bipolar transistor.
In each case, the power supply voltage Vcc is stabilized by flowing an extra current to the reference voltage line instead of directly limiting the current to the power supply voltage Vcc line.

The power supply circuit shown in FIG. 6A belongs to an intermittent control type constant voltage circuit unlike the above-described continuous control type constant voltage circuit. The shunt switching regulator 800 includes a switching transistor 802 provided between the rectifier 72 and the capacitor 73 between a power supply voltage Vcc line and a reference voltage line, and a switching transistor 802 for dividing the power supply voltage Vcc and a reference voltage. And a comparator 801 for controlling the switching of the switching transistor 802 according to the magnitude. Switching regulators have high efficiency and generate less heat in power supply circuits, and are suitable for miniaturization and are used in power supply units of various electronic devices.

[0017]

However, even with a switching regulator having such advantages,
It is not used for data storage that receives power and commands by electromagnetic inductive coupling. When the series regulator 80 is replaced with a shunt switching regulator 800 for the conventional data carrier 50, the power supply voltage Vcc gradually increases and then rapidly decreases to form a sawtooth wave (see FIG. 6B). The switching transistor 802 is turned on at the timing of the rapid drop, and a large current momentarily flows from the power supply voltage Vcc line to the reference voltage line. The instantaneous current influences the parallel resonance circuit of the transmission / reception coil 71, and a resonance state such as a short circuit is generated in the resonance circuit, and the reception unit of the reader / writer 10 in a state where the resonance state is coupled to the transmission / reception coil 71. 40 receiving coils 4
The switching noise including a large amount of resonance frequency components of the resonance circuit of the reception coil 41 also occurs in the reception unit 40.

Since the frequency f2 component contained in the noise cannot be completely removed and appears in the received signal C (FIG. 6)
(Refer to (c)), the response data cannot be correctly restored. Moreover, the reader / writer 10 and the data carrier 5
When the distance to 0 changes, the switching noise generation timing also changes. For example, when the distance increases, the switching noise generation interval increases (see FIGS. 6D and 6E). It can't be suppressed. For this reason, the intermittent control type constant voltage circuit was not used for the data storage unit even though it was used for the data reader.

On the other hand, in the case of the conventional structure using the continuous control type constant voltage circuit in the power supply section of the data storage body, the control elements such as the pass transistor 82 are large due to the large amount of heat generated in the power supply circuit. Due to the tendency to be formed and the fact that it is impossible to integrate the logic element into a single chip due to the difference in element structure, it has become difficult to reduce the size and thickness of the data storage body. Specifically, a series regulator requires a power transistor as a pass transistor, so it is difficult to reduce the size. In addition, since the voltage drop here is as large as about 0.7 V, communication between the data reading device and the data storage unit is correspondingly made. There is the disadvantage that the possible distance is reduced.

In the case of a Zener shunt regulator, the Zener diode is difficult to be miniaturized due to heat generation, and cannot be formed in a CMOS manufacturing process.
There is a disadvantage that mounting of a plurality of elements is unavoidable because the elements are separate from the MOS-IC. Moreover, since such an individual element is thicker than a CMOS-IC, a thickness of 0.78
There is no way to respond to thinning such as mm. Further, the bipolar shunt regulator also has a drawback that it is difficult to reduce the size because a power transistor is required, and is incompatible with the CMOS manufacturing process.

Therefore, the size and thickness of the data storage are reduced.
In order to reduce the cost, it is necessary to use an intermittent control type constant voltage circuit for the power supply unit of the data storage unit and to devise a data access method and device so as to eliminate an undesired influence of switching noise. The present invention has been made in order to solve such a problem, and an object of the present invention is to realize a data access method and a data access method capable of correctly communicating even if a switching noise source exists.

[0022]

Means for Solving the Problems First to fourth solving means invented to solve such problems are as follows.
The configuration and operation and effect will be described below.

[First Solution] A data access method according to a first solution (as described in claim 1 at the beginning of the application) is a method of electromagnetic induction using a mutual induction effect of coils or an induced electromagnetic field of an antenna. In a data access method in which power is supplied (between a data reader and a data storage) and commands (such as memory access) are transmitted and received by a coupling scheme (from the data reader to the data storage). When the command is transmitted, a predetermined dummy response is sent (from the data storage unit to the data reading device), and reception of response data (at the data reading device) is refrained for a predetermined period. And delays (at least so that the response data to the command is sent after sending the dummy response) a response to the command (by the data storage). That return and (according to the data reading device) of the response data, characterized in that the acceptance is carried out.

Here, the above-mentioned “period for performing a predetermined dummy response” and “predetermined period for refraining from receiving response data” are as follows.
When the resonance circuit of the electromagnetic induction coupling in the data storage unit and the resonance circuit of the electromagnetic induction coupling in the data reading unit are coupled, the resonance state corresponding to the resonance state in the data storage unit also corresponds to the data reading unit. It is determined based on the time until it occurs. Further, the data reading device only needs to have at least a function of reading data from the data storage body, and includes a data reading device.

In the data access method according to the first solution, a command such as data reading is transmitted from the data reading device and received by the data storage. The response data to the command is returned from the data storage unit to the data reading device after the dummy response is sent from the data storage unit to the data reading device, and is received by the data reading device. Communication for memory access and the like is performed between the device and the data storage.

In addition, during the communication, a dummy response is sent out from the data storage unit between the transmission of the command and the return of the response data, while the data reader does not accept the response data. During the transmission of the dummy response, in the data storage, the resonance circuit including the electromagnetic induction coupler is maintained in a constant resonance state by the driving at that time. And
In the data reading device, the resonance circuit including the reception electromagnetic induction coupler is brought into a fixed resonance state corresponding to the resonance state in the data storage body based on the electromagnetic induction coupling. Since this resonance state is induced by an explicit drive for sending a dummy response, the resonance state is generally stronger and more stable than that which occurs secondaryly or intermittently due to a switching current or the like in a power supply circuit. doing. at least,
After a lapse of a predetermined period, the state has reached a stable state.

[0027] Thus, while the data reading device is refraining from receiving response data, undesired switching noise due to switching current or the like in the data storage is suppressed and disappears or is reduced to a negligible level. Become. Therefore, the response data is received and demodulated without being affected by the operation of the switching noise generation source, so that communication for memory access between the data reading device and the data storage is correctly performed. Becomes

Therefore, according to the present invention, it is possible to realize a data access method capable of correctly communicating even if a switching noise source exists. As a result, an intermittent control type constant voltage circuit can be employed in the power supply unit of the data storage body.

[Second Solution] The data reading apparatus of the second solution (as described in claim 2 at the beginning of the application)
In a data reading device that sends power and sends a command by an inductive coupling method using a mutual induction action of coils or an induced electromagnetic field of an antenna, a data reading device sends (at least) a command for a predetermined period immediately after sending the command. Means for preventing receipt of response data (from the body) is provided.

In the data reading device of the second solution, the data access method of the first solution can be executed in cooperation with a data storage of a fourth solution described later. it can. Therefore, according to the present invention, it is possible to realize a data reading device capable of correctly communicating with a data storage even if a switching noise source exists.

[Third Solution] The data storage of the third solution (as described in claim 3 at the time of filing of the application) is an electromagnetic induction device utilizing a mutual induction effect of coils or an induction electromagnetic field of an antenna. A switching regulator is used in a power supply unit in a data storage unit that receives power and receives a command by a coupling method.

In the data storage unit of the third solution, the advantage of the switching regulator that it is efficient, generates less heat, and is suitable for miniaturization is incorporated in the power supply unit. Therefore, according to the present invention, the size, thickness and cost of the data storage can be reduced.

[Fourth Solution] The data storage device of the fourth solution is the data storage device of the third solution described above,
A predetermined dummy transmission is performed prior to returning response data to the command.

In the data storage medium of the fourth solution, the data access method of the first solution can be executed in cooperation with the data reading device of the second solution. Can be. Therefore, according to the present invention, it is possible to realize a data storage unit that can correctly communicate with the data reading device even if there is a switching noise source.

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The data access method and apparatus of the present invention achieved by such a solution will be described below.
An embodiment for implementing this will be described with reference to an embodiment.
First, the system configuration will be described with reference to the block diagram of FIG. 1. In the drawing, the same components as those in FIG. Are omitted, and the following description focuses on differences from the conventional example.

The reader / writer 100 differs from the conventional reader / writer 10 in that the command sending routine 21 is extended to a new command sending routine 210 and that the buffer 46 of the receiving unit 40 is connected to the AND gate 460 of the receiving unit 400. Is replaced by Command sending routine 210
Is extended so that a window pulse is sent to the reception enable signal B after a predetermined period has elapsed after the command is sent by the command signal A. This window pulse is determined so as to cover the return timing of response data from data carrier 500.

In addition to the detection signal D, the AND gate 460 sends the restoration data E generated from the detection signal D to the response reception routine 23 only while the reception enable signal B includes the window pulse. The reception enable signal B is also input. As a result, the data reading device 100 refrain from receiving response data for a predetermined period immediately after sending the command.

The difference between the data carrier 500 and the conventional data carrier 50 is that the transmitting unit 61 is different from the new transmitting unit 6.
10 and that the series regulator 80 is replaced by the shunt switching regulator 800 described above. Thus, the data storage unit 500 uses a switching regulator in the power supply unit.

Further, when receiving the response data to be returned from the control unit 63, the transmitting unit 610 places dummy data of a predetermined length before the response data, and then transmits them in order. I have. Dummy data includes data of all bits “0” and data of all bits “1”.
Those which do not significantly modulate the carrier and which can be distinguished and distinguished from the start bit of the response data are used. Thus, the data storage unit performs a predetermined dummy transmission before returning response data to the command.

The extension of the transmitting section 610 is C
When integrated on a MOS-IC or the like, the data carrier 50
There is almost no effect on the size of 0. Furthermore, the comparator 801 and the switching transistor 802 can also be made CMOS, and in such a case,
The shunt switching regulator 800 can also be integrated into one chip together with the logic unit 60, and the size of the data carrier 500 can be further reduced.

The mode of use and operation of the data access system having such a configuration will be described with reference to the drawings. 2A and 2B show an example of a signal waveform at the time of the system operation and are compared with FIG. 4 of the conventional example. FIG. 2A shows the waveform of the command signal A, FIG. 2B shows the waveform of the reception enable signal B, and FIG. c) is the waveform of the received signal C, and (d) is the detected signal D.
(E) shows the waveform of the restored data E.

When the data carrier 500 is brought close to the reader / writer 100 while the reader / writer 100 is transmitting a carrier wave of the frequency f1, an induced current flows through the transmission / reception coil 71 in the data carrier 500, and the power supply unit, that is, the rectifier 72 is connected. Shunt switching regulator 80
0 and the capacitor 73, the power supply voltage V
The power of cc is generated, and the logic unit 60 and the entire data carrier 500 become operable.

In this manner, power is supplied from the reader / writer 100 to the data carrier 500 by the electromagnetic inductive coupling system utilizing the mutual induction action of the coils, as in the related art. However, the shunt switching regulator 800 in the data carrier 500 uses a switching transistor. 802 repeats switching. Then, in the receiving unit 400 of the reader / writer 100, the switching noises C11, C21, and C31 appear in the received signal C (see FIG. 2C). Noise is also seen in the corresponding part of the detection signal D (see FIG. 2D). However, at this time, the reception enable signal B is not significant (see FIG. 2).
(See (b)), but it is not received as the restored data E by the response receiving routine 23 (see FIG. 2E).

In this state, if there is a predetermined initial communication or the like, if it has been completed, a data reading command A1 is issued from the command sending routine 210 of the reader / writer 100 (FIG. 2).
(See (a)), which is transmitted to the data carrier 500 via the transmission unit 30. In the data carrier 500, the transmission / reception coil 71 and the reception unit 65 receive the command, and the control unit 63 responds to the command to the memory 64.
The corresponding data is read out from, and the data is passed to the transmitting unit 610 as response data.

As described above, the response data is prepared for the return to the reader / writer 100 in the same manner as in the related art. However, the transmission unit 610 of the data carrier 500 does not immediately start sending the response data. First, a dummy response is transmitted, and thereafter, response data is transmitted. Then, after an unmodulated carrier is transmitted from the data carrier 500 to the reader / writer 100,
The modulated carrier carrying the response data will be transmitted.

Receiving this, in the reader / writer 100, after transmitting the command A1, the reception section 400 obtains a reception waveform C12 of a dummy response (see FIG. 2B). Since the waveform C12 quickly stabilizes, noise disappears in the portion D12 of the detection signal D corresponding to the latter half (see FIG. 2D). In addition, a window pulse B1 is transmitted to the reception enable signal B by the command transmission routine 210 at a timing before the rear end of the dummy response (see FIG. 2B), and the detected signal D is restored data E from the point where the noise has disappeared. Will be reflected in.

In such a state, if the reception section 400 continuously obtains the reception waveform C1 of the response data (see FIG. 2C), the detection waveform D1 of the response data is also obtained (FIG. 2). (See (d)), and the restored data E1 is obtained via the AND gate 460 (see FIG. 2E). Thereafter, the state returns to the state where the switching noise C21 appears in the received signal C (see FIG. 2C). However, since the window pulse B1 of the received enable signal B also ends (see FIG. 2B), the restored data E is incorrect. It is not accepted (see FIG. 2E).

When a data write command A2 is issued from the reader / writer 100 (see FIG. 2A), a dummy response is transmitted from the data carrier 500 in the same manner. Response data is also returned. Then, in the reader / writer 100, the received waveform C22 of the dummy response is stabilized (see FIG. 2B), noise disappears in the corresponding portion D22 of the detection signal D (see FIG. 2D), and the response data Received waveform C2 (FIG. 2)
(C), the detected waveform D2 (see FIG. 2 (d)), and the restored data E2 (see FIG. 2 (e)) can be obtained exactly as before the introduction of the shunt switching regulator 800.

When the command is transmitted by the reader / writer 100 in this way, a predetermined dummy response is transmitted by the data carrier 500, and the reception of response data is refrained by the reader / writer 100 for a predetermined period. The return of the response data to the command is performed by the data carrier 500, and the reception is performed by the reader / writer 100.

[0050]

As is apparent from the above description, in the data access method according to the first solution of the present invention, a dummy response is sent out while the response data is not being received, and a strong and stable response is obtained. By establishing the resonance state, there is an advantageous effect that a data access method capable of correctly communicating even when there is a switching noise source can be realized.

Further, in the data reading device of the second solving means and the data storage of the fourth solving means of the present invention, when they cooperate, the data access method of the first solving means is executed. Thus, there is an advantageous effect that a data reading device and a data storage unit that can correctly communicate even if there is a switching noise generation source can be realized.

Further, in the data storage device according to the third solution of the present invention, the advantages of the switching regulator are incorporated in the power supply unit, and the size, thickness, and cost of the data storage device can be reduced. There is an advantageous effect that it is possible.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of a system that executes a data access method of the present invention.

FIG. 2 is an example of the signal waveform.

FIG. 3 is a block diagram of a conventional system.

FIG. 4 is an example of the signal waveform.

FIG. 5 is an example of the power supply circuit.

FIG. 6 shows another power supply circuit and a signal waveform example.

[Explanation of symbols]

Reference Signs List 10 reader / writer (data reading device, data access system) 20 microprocessor (arithmetic control unit) 21 command transmission routine 22 application routine 23 response reception routine 30 transmission unit 31 modulation circuit (transmission unit) 32 amplifier (transmission unit) 33 transmission coil (Electromagnetic induction coupler, transmitting section) 40 Receiving section 41 Receiving coil (Electromagnetic induction coupler, receiving section) 42 Bandpass filter (receiving section) 43 Amplifier (receiving section) 44 Clock extraction circuit (demodulation circuit, receiving section) 45 Synchronous detection circuit (demodulation circuit, reception unit) 46 Buffer (binarization circuit, waveform shaping circuit, demodulation circuit, reception unit) 50 Data carrier (data storage unit, data access system) 60 Logic unit (logic circuit unit) 61 Transmission Section (means for returning response data) 62 driver (coil driving means) 63 control Unit (means for generating response data) 64 Memory (means for holding response data etc.) 65 Receiver (means for receiving commands) 66 Receiver (coil voltage responsive means) 71 Transmitter / receiver coil (electromagnetic induction coupler) 72 Rectifier (power supply) Circuit input stage, power supply section 73 Capacitor (power supply circuit output stage, power supply section) 80 Series regulator (continuous control type constant voltage circuit,
Power supply unit) 81 Operational amplifier 82 Pass transistor 83 Zener shunt regulator (Continuous control type constant voltage circuit) 84 Bipolar shunt regulator (Continuous control type constant voltage circuit) 100 Reader / writer (Data reader, Data access system) 210 Command sending routine (Command) 400 receiving unit 460 AND gate (means for waiting for response data reception immediately after command transmission) 500 data carrier (data storage unit, data access system) 610 transmission unit (before returning response data) Means for performing dummy transmission) 800 Shunt switching regulator (intermittent control type constant voltage circuit) 801 Comparator 802 Switching transistor

──────────────────────────────────────────────────の Continuing on the front page (51) Int.Cl. ⁶ Identification code FI H04B 5/02 G06K 19/00 H (72) Inventor Megumi Iiyama 1006 Kazuma Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. ( 72) Inventor Shinkichi Asaka 1006 Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd.

Claims (4)

[Claims] In a data access method in which power is supplied and a command is transmitted / received by an electromagnetic induction coupling system utilizing an induction action of a coil or an induction electromagnetic field of an antenna, a predetermined dummy response is transmitted when the command is transmitted. And a response data reception is refrained for a predetermined period of time, and response data is returned and received in response to the command with a delay. 2. A data reading apparatus for supplying power and sending a command by an electromagnetic induction coupling method using a mutual inductive action of a coil or an induction electromagnetic field of an antenna, wherein response data is received for a predetermined period immediately after sending the command. A data reading device provided with a copy means. 3. A data storage device which receives power and commands by an electromagnetic induction coupling method using mutual induction of coils or an induction electromagnetic field of an antenna, wherein a switching regulator is used in a power supply unit. Data storage. 4. A data storage unit according to claim 3, wherein a predetermined dummy transmission is performed before returning response data to said command.