JPH0786994A - Communication device using electromagnetic inductive coupling - Google Patents

Abstract

(57) [Summary] [Purpose] To increase the communication distance when supplying power by electromagnetic induction coupling to a communication device that does not have a power source such as a battery and performing bidirectional communication. A magnetic body 2 is formed on a printed circuit board 1, and a coil 14a is wound around the magnetic body 2 so that the reception magnetic field of the magnetic body 2 is spatially orthogonal to the transmission magnetic field of the transmission coil 13. It is configured. Reader / writer 1
Although the 0 side constantly transmits a signal to the memory module 20, the receiving coil 14 of the reader / writer 10 does not generate electromagnetic induction because its receiving magnetic field is spatially orthogonal to the sending magnetic field of the transmitting coil 13. When the reader / writer 10 and the memory module 20 come close to each other, the transmitter coil 13 of the reader / writer 10 is inserted into the receiver coil 21 of the memory module 20.
An alternating current is induced by electromagnetic induction by, and this alternating current is applied to the power supply circuit 27 to be rectified and smoothed to generate a power supply voltage + Vcc in the memory module 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication device using electromagnetic induction coupling for supplying bidirectional communication while supplying power to a communication device having no power source such as a battery by electromagnetic induction coupling.

[0002]

2. Description of the Related Art FIG. 6 shows an example of a communication device using electromagnetic induction coupling, for a data storage body (memory module) 20 having no power source such as a battery, from a reader / writer 10 driven by a commercial power source. A data transmission system for writing and reading data while supplying power by electromagnetic inductive coupling is shown. This configuration was proposed by the applicant in Japanese Patent Application No. 3-27061.

In FIG. 6, a reader / writer 10 includes a controller (MPU) 11, an FSK modulator 12 and a coil 13 for transmission, a coil 14 for reception, and a reference memory 15.
The memory module 20 includes a receiving coil 21 and an FSK demodulator 22, a controller (MPU) 23, and a non-volatile memory (for example, EEPRO).
M) 24, a pseudo random signal generator 25 for transmission and a coil 26 for transmission, and a power supply circuit 27 for generating power from a received signal from the reader / writer 10.

The controller 11 on the side of the reader / writer 10 executes write control and read control for the memory module 20, and commands, data, etc. from the controller 11 are transmitted by the FSK modulator 12 at a bit "1" and a frequency f.
It is modulated into a combination of two frequency signals of frequency f2 with 1 and bit "0" and supplied to the transmission coil 13. When the reader / writer 10 and the memory module 20 come close to each other as shown in the figure, alternating current is induced in the receiving coil 21 of the memory module 20 by electromagnetic induction by the transmitting coil 13 of the reader / writer 10, and this alternating current is applied to the power supply circuit 27. Rectified and smoothed, power supply voltage in memory module 20 +
Vcc is generated. Further, the signal received by the receiving coil 21 is demodulated into bits "1" or "0" by the FSK demodulator 22, and the controller 23 executes the reading of the non-volatile memory 24 in the case of a read command based on this signal. To do.

In the case of a write command, after the reply command from the controller 23 is converted into serial data, it is applied bit by bit to the pseudo random signal generator 25 to be converted into a pseudo random sequence signal, and the transmission coil 26. The pseudo random signal generator 25
As the pseudo-random signal generated by, for example, when the length is 15 words (= 2 ⁴ −1), the data can be held in advance and the data can be sequentially transmitted.

The pseudo random signal supplied from the transmission coil 26 of the memory module 20 is induced in the reception coil 14 of the reader / writer 10 by electromagnetic induction, and the correlation circuit 1
6 calculates the autocorrelation between this received signal and the pseudo random signal stored in the reference memory 15 on the memory module 20 side. If the correlation value is equal to or more than the threshold value, the power supply voltage + Vcc in the memory module 20 is sufficient. If there is, write is executed.

That is, in the above communication protocol, during reading, that is, when the reader / writer 10 receives from the memory module 20, the reader / writer 10 intermittently transmits a signal such as a read command and suspends transmission. Is produced, and the receiving state from the memory module 20 is maintained only during that period.

[0008]

By the way, in such a system, a relatively high output is emitted from the transmission coil 13 on the reader / writer 10 side driven by, for example, a commercial power source, and a signal received from the reader / writer 10 is emitted. Relatively low power is emitted from the transmitter coil 26 of the powered memory module 20.

Therefore, in such a communication system, when a read command is executed, that is, when a current is induced in the receiving coil 14 of the reader / writer 10 by the transmitting coil 26 of the memory module 20, the transmitting coil on the side of the reader / writer 10 is used. If you do not stop the output from 13,
The signal induced in the receiving coil 14 of the reader / writer 10 is only the signal from the transmitting coil 13 on the reader / writer 10 side, and the signal from the transmitting coil 26 of the memory module 20 cannot be received. Therefore, the reader / writer 1
The output from the transmission coil 13 on the 0 side must be stopped.

Therefore, in such a communication device using electromagnetic induction coupling, since the memory module 20 is supplied with power from the reception signal from the reader / writer 10, the output from the transmission coil 13 on the reader / writer 10 side is stopped. Then, there is a problem that the operation is stopped after a certain time depending on the charging capacitor, and as a result, the communication distance is shortened.

In the example shown in FIG. 6, the reader / writer 1
0 and the memory module 20 can drive only one of the transmission coil and the reception coil, but as another example, the reader / writer 10 and the memory module 20 each include one transmission / reception coil, and this transmission / reception coil is switched. The same problem occurs when driving by driving. Incidentally. This configuration requires a circuit for switching the transmission / reception coil.

In view of the above conventional problems, the present invention supplies a power source by electromagnetic induction coupling to a communication device having no power source such as a battery and extends the communication distance when bidirectional communication is performed. It is an object of the present invention to provide a communication device using electromagnetic induction coupling that can be performed.

[0013]

In order to achieve this object, the present invention provides a first communication device having a first transmitter coil and a first receiver coil, a second transmitter coil and a second transmitter coil.
And a second communication device which uses the voltage induced in the second reception coil as a power source and which performs bidirectional communication by using electromagnetic induction coupling. In the above, the first transmission coil and the first reception coil are arranged such that the transmission magnetic field of the first transmission coil and the reception magnetic field of the first reception coil are spatially orthogonal to each other, and the first communication device is It is characterized in that a signal is constantly transmitted through one transmission coil and reception is performed through the first reception coil.

Specifically, a first transmission coil is formed by forming a conductive thin film on a printed circuit board, a magnetic body is formed on the printed circuit board, and the first coil is wound around the magnetic body. A receive coil is formed. Further, specifically, the first transmitting coil is formed by winding the coil around the bobbin, and the first receiving coil is formed by forming the magnetic body on the bobbin and winding the coil around the magnetic body.

Magnetic members are formed on the printed circuit board or the bobbin so as to cross each other in a cross shape, and a coil is wound around each magnetic member to form a first receiving coil.

[0016]

In the present invention, the first transmitting coil and the first receiving coil of the first communication device are arranged so that the sending magnetic field of the first transmitting coil and the receiving magnetic field of the first receiving coil are spatially orthogonal to each other. Since it is arranged, no current is induced in the first receiving coil by the magnetic field sent from the first transmitting coil,
Even if the communication device of (1) always sends a signal through the first transmission coil, a current is induced in the first reception coil by the magnetic field sent from the second transmission coil of the second communication device.

Therefore, when the first communication device and the second communication device are in close proximity to each other, the power can always be supplied from the first communication device to the second communication device by electromagnetic induction coupling. The distance can be lengthened.

[0018]

1 shows an example of a transmitting coil 13 and a receiving coil 14 of a reader / writer 10 shown in FIG. 6 as an example of a communication device using electromagnetic inductive coupling according to the present invention, and in particular, FIG. Is a plan view, and FIG. 1B is a side view. In FIG. 1, the transmission coil 13 is, for example, a circular printed circuit board 1.
It is configured by forming a conductive thin film 13a in a spiral shape on the upper side, and therefore, the transmission coil 13 is wound around the printed board 1 in the thickness direction as an axis. Further, a magnetic body 2 such as an amorphous sheet is attached or painted on both surfaces of the printed circuit board 1 substantially at the center thereof so that the magnetic field received by the magnetic body 2 is spatially orthogonal to the magnetic field transmitted by the transmission coil 13. Further, the receiving coil 14 is configured by winding the coil 14a around the horizontal direction of the printed circuit board 1. The coil 14a is wound around the magnetic body 2 through a through hole formed in the printed board 1.

FIG. 2 shows the transmission coil 13 of the reader / writer 10.
And another example of the receiving coil 14, and the memory module 20.
An example of the receiving coil 21 and the transmitting coil 26 of FIG. In FIG. 2, the reader / writer 10 side and the memory module 2 are
Although the 0 side is shown to have the same size, the size on the memory module 20 side is actually quite small. In this example, the transmission coil 13 of the reader / writer 10 is formed by forming a conductive thin film 13a in an arc shape on the printed board 1a, and the receiving coil 14 is formed on the printed board 1a.
A magnetic body 2a such as an amorphous sheet is attached or painted on both surfaces in the substantially central part of the coil 14a, and the coil 14a is wound around the magnetic body 2a so that the reception magnetic field is spatially orthogonal to the transmission magnetic field of the transmission coil 13. It is composed of The transmission coil 13 is the FSK modulator 12 shown in FIG.
The receiving coil 14 is connected to the correlation circuit 16.

Receiving coil 21 of memory module 20
Is formed by forming a conductive thin film in an arc shape on the printed board 1b similarly to the transmission coil 13 of the reader / writer 10, and the transmission coil 26 is formed by the transmission coil 26.
Similar to the receiving coil 14, the magnetic body 2 such as an amorphous sheet is attached or painted on the printed circuit board 1b at substantially the center thereof, and the transmission magnetic field is spatially orthogonal to the reception magnetic field of the reception coil 21 on the magnetic body 2b. It is configured by winding a coil as described above.

The circuit IC chip 3 of the memory module 20 shown in FIG. 6 is mounted on the printed circuit board 1b.
The reception coil 21 is connected to the FSK demodulator 21 in the chip 3 and the power supply circuit 27, and the transmission coil 26 is connected to the pseudo random signal generation circuit 25. Further, the memory module 20 is formed in various shapes such as a card type, a coin type, a square type, etc. as shown by a broken line so that it can be easily carried.

FIG. 3 shows the transmitter coil 13 and the receiver coil 14 of the reader / writer 10 shown in FIG. 2 and the memory module 20.
The electromagnetic induction coupling state of the receiving coil 21 and the transmitting coil 26 is shown. The magnetic flux sent from the transmission coil 13 of the reader / writer as shown in the arrow A direction is electromagnetically induced in the reception coil 21 of the memory module 20, but the reception magnetic field is transmitted to the reception coil 14 of the reader / writer 10. Electromagnetic induction does not occur because it is spatially orthogonal to the sending magnetic field of the coil 13. Similarly, electromagnetic induction does not occur in the transmission coil 26 of the memory module 20. Further, the direction of the magnetic flux sent from the transmitting coil 26 of the memory module 20 intersects with the receiving coil 14 of the reader / writer 10, so that the receiving coil 14 of the reader / writer 10 can receive it.

FIGS. 4 and 5 show other examples of the transmission coil 13 and the reception coil 14 of the reader / writer 10. In this example, the bobbin 4 is formed into a thin, substantially cylindrical shape, a groove is formed in the circumferential direction, and the coil 13a is wound along this groove to form the transmission coil 13.
A magnetic substance 2 such as an amorphous sheet is attached or painted on the both surfaces of the bobbin 4 substantially at the center thereof, or is formed by vapor deposition or sputtering. The magnetic field received by the magnetic substance 2 is transmitted from the transmitting coil 13. The receiving coil 14 is configured by winding the coil 14a so as to be spatially orthogonal to. Also in this case, the magnetic flux sent from the transmission coil 13 of the reader / writer is the same as the direction A shown in FIG. 3, and therefore, the magnetic flux does not cause electromagnetic induction in the reception coil 14.

The orthogonal relationship between the receiving coil 21 and the transmitting coil 26 on the memory module 20 side is less strict than that between the transmitting coil 13 and the receiving coil 14 of the reader / writer 10. This is because the transmission magnetic field on the memory module 20 side is less than the reception power, and therefore the IC chip 3 is not destroyed. May have some errors. On the other hand, the reader / writer 10
It is desirable that the transmission coil 13 and the reception coil 14 are arranged such that the respective magnetic fields are spatially orthogonal to each other in the same plane in order to increase the reception sensitivity and the transmission power.

In the above-described embodiment, the receiving coil 14 of the reader / writer 10 is constructed by winding the coil 14a around the printed board 1, 1a or the magnetic body 2, 2a on the bobbin 4. In this embodiment, two magnetic bodies 2 and 2a may be formed on the printed circuit boards 1 and 1a and the bobbin 4 so as to be orthogonal to each other in a cross shape, and a coil 14a may be wound around each magnetic body 2 and 2a. Good. In this respect, the transmission coil 26 on the memory module 20 side is also configured in the same manner.

Next, a communication method when such a transmission / reception coil is applied to the data transmission device shown in FIG. 6 will be described. Commands and data from the controller 11 of the reader / writer 10 are modulated by the FSK modulator 12 into a combination of two frequency signals of frequency "f1" at bit "1" and frequency "f2" at bit "0" and supplied to the transmission coil 13. . In this case, the reader / writer 10 side constantly transmits an access command such as a read command to the memory module 20, but the reception coil 14 of the reader / writer 10 has a reception magnetic field spatially different from the transmission magnetic field of the transmission coil 13. Since it is orthogonal to, electromagnetic induction does not occur.

When the reader / writer 10 and the memory module 20 come close to each other as shown in FIG. 3, alternating current is induced in the receiving coil 21 of the memory module 20 by electromagnetic induction by the transmitting coil 13 of the reader / writer 10, and this alternating current is supplied to the power source. The voltage is applied to the circuit 27, rectified and smoothed, and the power supply voltage + Vcc in the memory module 20 is generated. Further, the signal received by the receiving coil 21 is demodulated into bits "1" or "0" by the FSK demodulator 22, and the controller 23 executes the reading of the non-volatile memory 24 in the case of a read command based on this signal. To do.

In the case of a write command, after the reply command from the controller 23 is converted into serial data, it is applied to the pseudo random signal generator 25 bit by bit and converted into a pseudo random sequence signal, and the transmission coil 26. The pseudo random signal supplied from the transmission coil 26 of the memory module 20 is induced in the reception coil 14 of the reader / writer 10 by electromagnetic induction, and the correlation circuit 16 causes the reception signal and the memory module 20 side previously stored in the reference memory 15. The autocorrelation with the pseudo random signal is calculated, and when the correlation value is equal to or more than the threshold value, it is determined that the power supply voltage + Vcc in the memory module 20 is sufficient, and writing is executed.

That is, in the above communication protocol, since the reader / writer 10 constantly transmits a signal at the time of reading, that is, when the reader / writer 10 receives from the memory module 20, the memory module 20 is close to the reader / writer 10. As long as the received signal is supplied with power, the communication distance can be extended. Further, since the reader / writer 10 constantly transmits a signal, a clock can be supplied from the reader / writer 10 to the memory module 20 by using this signal, and in this case, an oscillator for clock generation is omitted from the memory module 20. Therefore, there is also an effect that the power consumption and the size of the memory module 20 can be reduced.

Further, the communication device of the present invention is different from the one in which the reader / writer 10 and the memory module 20 each have one transmission / reception coil, and this switching transmission / reception coil is used for switching, so that the transmission / reception coil is switched. No circuit is required.

[0031]

As described above, according to the present invention, the first communication device having the first transmitting coil and the first receiving coil, and the second transmitting coil and the second receiving coil are provided. A communication device using electromagnetic induction coupling that performs bidirectional communication with the second communication device that uses the voltage induced in the second receiving coil as a power source together with the first communication device. Of the first transmitting coil and the first receiving coil are arranged such that the sending magnetic field of the first transmitting coil and the receiving magnetic field of the first receiving coil are spatially orthogonal to each other, and the first communication device includes the first transmitting coil. Since the signal is always transmitted through the first receiving coil while receiving the signal, the magnetic field transmitted from the first transmitting coil does not induce a current in the first receiving coil, and the first communication device is Even if the signal is always sent through the first transmitting coil, the second A current is induced in the first receiving coil by the magnetic field sent from the first transmitting coil of the communication device, so that when the first communication device and the second communication device are in close proximity, Since the power can be always supplied to the second communication device by electromagnetic induction coupling, the communication distance can be lengthened.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment showing an example of a transmitter coil and a receiver coil of a reader / writer as an embodiment of a communication device using electromagnetic induction coupling according to the present invention.

FIG. 2 is a configuration diagram of an embodiment showing another embodiment of a transmitter coil and a receiver coil of a reader / writer and an embodiment of a receiver coil and a transmitter coil of a memory module according to the present invention.

3 is an explanatory diagram showing an electromagnetic induction coupling state of a transmitter coil and a receiver coil of the reader / writer of FIG. 2 and a receiver coil and a transmitter coil of a memory module.

FIG. 4 is a perspective view showing still another embodiment of the transmission coil and the reception coil of the reader / writer according to the present invention.

5 is a side view showing the transmitter coil and the receiver coil of FIG. 4;

FIG. 6 is a block diagram showing a reader / writer and a memory module of a communication device using electromagnetic inductive coupling, which the present inventors have already proposed.

[Explanation of symbols]

 1, 1a, 1b: Printed circuit board 2, 2a, 2b: Magnetic material 3: Memory module IC chip 4: Bobbin 10: Reader / writer 11, 23: Controller 12: FSK modulator 13, 26: Transmission coil 13a: Conductive thin film 13b: coil 14, 21: receiving coil 14a: coil 15: reference memory 16: correlation circuit 20: memory module 22: FSK demodulator 24: non-volatile memory 25: pseudo random signal generator

Claims (5)

[Claims] 1. A first communication device having a first transmitting coil and a first receiving coil, a second transmitting coil and a second receiving coil, and being induced in the second receiving coil. In a communication device using electromagnetic inductive coupling that performs two-way communication by electromagnetic inductive coupling with a second communication device that uses a current as a power source, the first transmitting coil and the first receiving coil are The transmitting magnetic field of the first transmitting coil and the receiving magnetic field of the first receiving coil are arranged so as to be spatially orthogonal to each other, and the first communication device always transmits a signal via the first transmitting coil. A communication device using electromagnetic induction coupling, characterized in that reception is performed via a first receiving coil. 2. A communication device using electromagnetic induction coupling according to claim 1, wherein the first transmission coil is formed by forming a conductive thin film on a printed circuit board, and at the same time, on the printed circuit board. A communication device using electromagnetic induction coupling, characterized in that the first receiving coil is formed by forming a magnetic body and winding a coil around the magnetic body. 3. A communication device using electromagnetic induction coupling according to claim 1, wherein a coil is wound around a bobbin to form the first transmission coil, and a magnetic material is formed on the bobbin. By winding a coil around the magnetic body, the first
A communication device using electromagnetic induction coupling, characterized in that a receiving coil of the above is formed. 4. The communication device using electromagnetic induction coupling according to claim 1, wherein the magnetic body is formed on the printed circuit board or the bobbin so as to cross in a cross shape, and a coil is wound around each magnetic body. Accordingly, the communication device using electromagnetic induction coupling is characterized in that the first receiving coil is formed. 5. A communication device using electromagnetic induction coupling according to claim 1, wherein the second communication device has a non-volatile memory for storing data. The first communication device controls writing and reading of the non-volatile memory, and is a communication device using electromagnetic inductive coupling.