JPH03111987A - Information processing system using electromagnetic coupling type card - Google Patents

Abstract

PURPOSE:To reduce the impedance of a coil for power supply, to reduce energy consumption, to enlarge the impedance of a coil for communication and to make a current to small by providing the coil for power supply inside, and providing the coil for data communication outside. CONSTITUTION:In an IC card 2, a reception coil 3b of a power supply system wound around a disk-shaped core 18 is arranged in a center part and outside, a transmission/reception coil 4b for signal system is provided. On the side of a reader/writer 1, a transmission coil 3a of the power supply system is divided into coils 3a-1 and 3a-2 and a core 14 is formed to be C-shaped or U-shaped with a gap 19 to which a core 18 of the IC Card 2 is inserted. A transmission/ reception coil 4a of the signal system is arranged outside. For the coil of the power supply system, the energy consumption is reduced since the impedance is low and for the coil of the signal system, the small current can do since the impedance is high.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an information processing system for an electromagnetically coupled card, and more specifically, the present invention relates to an information processing system for an electromagnetically coupled card. This invention relates to improvements in electromagnetic coupling circuits in electromagnetic coupling type IC cards that exchange data between cards.

[Prior Art] In a conventional electromagnetic coupling type IC card, for example, a coil receives vibrating magnetic Qi energy supplied from a reader/writer, etc., and the rectifying circuit receives the vibrating magnetic Qi energy.

The DC voltage of this smoothing circuit is received by a smoothing circuit, and then stepped down by a constant voltage circuit such as a regulator or Zener diode to obtain stable constant voltage power.

[Problem to be solved] By providing such a voltage stabilizing circuit,
It reduces voltage fluctuations due to differences in the distance between the reader/writer and the IC card, absorbs voltage fluctuations due to changes in the current consumption of the IC card, and thereby prevents the power supply voltage itself on the IC card side from fluctuating. There is. However, because the efficiency of electromagnetic coupling is not good in the conventional method, a relatively large amount of power must be supplied from the outside, and the power fluctuations due to differences in the insertion state are also large, resulting in large power losses. be.

As a non-contact type IC card of this kind, JP-A-63-20
No. 587 can be mentioned. This is a structure in which a coil is built into the center of the front of the IC card in order to improve the reliability of the IC card connection and eliminate incorrect insertion. In this case, since power is transmitted by coupling using air-core coils, the amount of attenuation increases when magnetically coupled, and the supplied power is affected by variations in the distance between each other and the size of devices and IC cards. It's easy to accept. Furthermore, the above relationship applies not only to the power supply but also to the transmission system. In particular, when a coil with low DC resistance is used as the transmitter/receiver coil of the signal transmission system, the power consumed during data transmission increases. This has no choice but to require more power to be supplied from outside.

It is an object of the present invention to provide an information processing system for an electromagnetically coupled card that can solve the problems of the prior art, efficiently supply power, and transmit or receive data while reducing power consumption. With the goal.

[Means for Solving the Problems] The structure of the information processing system for an electromagnetically coupled card of the present invention to achieve the above object is such that on the side of an external device into which an information card such as an IC card is inserted, A core with high magnetic permeability is disposed in the core, a first coil is provided for supplying power in the form of magnetic energy to the information card, and a coil is provided outside the first coil for transmitting and receiving data to and from the information card. A second coil is provided, and on the information card side, a third coil having a high magnetic permeability core arranged inside and magnetically coupled to the first coil is provided, and further a third coil is provided. A fourth coil is provided outside the coil and electromagnetically coupled to the second coil.

[Effects] In this way, by arranging power supply coils inside both the external device and the information card, the inductance of the coil itself can be reduced, reducing its internal resistance and reducing DC power consumption. can.

Moreover, since a core is provided inside the coil, even if the coil has a small inductance, the overall inductance can be increased when connecting an external device and an information card, and power can be efficiently transmitted through close coupling.

On the other hand, since the transmitting/receiving coils for transmitting and receiving data are both placed outside the power supply coil, their inductance can be increased, and the internal impedance can be increased, allowing the current to flow during transmission in the signal transmission system. can be kept small.

As a result, by reducing the DC power consumed during data transmission, both the power supply system and the signal transmission/reception system can transmit power and information with high power efficiency.

[Embodiment] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an explanatory diagram of an electromagnetic coupling part in an IC card information processing system according to an embodiment to which the electromagnetically coupled card information processing system of the present invention is applied, and FIG. The block diagram, Figure 3, is
FIG. 2 is an explanatory diagram of frequencies used in the power supply system and the bow system and their transmission characteristics.

In FIG. 2, reference numeral 1 denotes an IC card reader into which a magnetically coupled IC card 2 (hereinafter simply referred to as IC card 2) is inserted.
A writer (hereinafter referred to as a reader/writer) with an IC card 2
The power source is supplied from the oscillation circuit 7 of the reader/writer 1 to the filter 5d.

The signal is received by the receiving coil 3b which is magnetically coupled to the transmitting coil 3a in a non-contact manner via the transmitting coil 3a. In this case, the oscillation circuit 7 is
For example, a signal of several +-kHz to several hundred kilohertz is supplied to the transmitting coil 3a, and the receiving coil 3b receives this signal in the form of a magnetic field, thereby transmitting power. This power received by the receiving coil 3b is then applied to the rectifier circuit 9 via the filter 5b, where it is converted to smoothed DC voltage power and stabilized by the constant voltage circuit 10 to, for example, I)C5V. The signal is converted into a digitized signal and supplied to each circuit inside the IC card 2.

Note that 8 is a power supply circuit (
(DC power supply), which supplies power to the oscillation circuit 7 as well as to each circuit inside the oscillation circuit 7.

Here, the data sent from the reader/writer 1 to the IC card 2 is transmitted from an arithmetic processing circuit 13 having a microprocessor or the like to a modulation circuit 11 as a transmitting circuit connected thereto. Filter 8a.

The signal is sent out via the transmitter/receiver coil 4a. The modulation circuit 11 has a carrier wave generation circuit inside, and has, for example, an IMH
A carrier wave with a frequency of approximately z is generated internally, and this carrier wave becomes “ON-
By being turned off, a transmission signal is generated, and this transmission signal is applied to the transmission/reception coil 4a. That is, the data transmission here is performed by the tone burst method.

In this way in the form of tone bursts the filter 6a,
Data transmitted in the form of magnetic flux through the transmitting/receiving coil 4a is received by the transmitting/receiving coil 4b of the IC card 2, which is magnetically coupled to the transmitting/receiving coil 4a in a non-contact state, and is demodulated into a digital signal by the demodulating circuit 16, which is a receiving circuit, after passing through the filter 6b. The data is then sent to an arithmetic processing circuit 17 having a microprocessor or the like.

On the other hand, data transmission from the IC card 2 to the reader/writer 1 is performed using the tone burst method as described above, and the modulation circuit 11 of the reader/writer 1 is stopped under the control of the arithmetic processing circuit 13. , the demodulation circuit 12 as a receiving circuit is activated.

Therefore, the arithmetic processing circuit 17 operates the modulation circuit 15 as a transmission circuit whose output side is connected to the connection point between the filter 6b of the IC card 2 and the demodulation circuit 16, and the data is transmitted to the reader/writer 1.

Like the modulation circuit 11, the modulation circuit 15 has an internal carrier wave generation circuit, and similarly generates a carrier wave with a frequency of about IMHz internally. A transmission signal is generated by being turned “ON-OFF”. Then, it is applied to the transmitting/receiving coil 4b to perform data transmission.

Note that the arithmetic processing circuits 13 and 17 include microprocessors 13a and 17a and memory 13b, respectively.

17b, and the memories 13b and 17b each contain transmission data of the other party processed by the microprocessor 13 at 17a, and data to be transmitted to the other party are read out at the time of data transmission. . These memories are usually composed of EEPROM, SRAM, or the like. Further, 20 is a host computer that exchanges information with the reader/writer 1.

Through the operation shown below, the IC card 2 receives power from the reader/writer 1, and data is exchanged between the reader/writer 1 and the IC card 2. Here, power is transmitted and received. Transmitting coil 3a and receiving coil 3 in relationship
b are each provided with a core 14,18. FIG. 1 shows the relationship between the transmitting coil 3 a + receiving coil 3b of the power supply system and the transmitting/receiving coils 4 a and 4 b of the signal system.

FIG. 1(a) shows the arrangement of the coils of the IC card 2, in which a receiving coil 3b of the power supply system wound around a disc-shaped core 18 is arranged in the center, and a signal A system transmission/reception coil 4b is arranged and embedded inside the IC card 2.

The relationship between the receiving coil of the power supply system and the transmitting/receiving coil of the No. 6 system is the same for the reader/writer 1 as well.

In (b) of the same figure, the mutual relationship between them is reduced, and the IC
When the card 2 is inserted into the reader/writer 1, the I
A transmitter coil 3a and a transmitter/receiver coil 4a of the reader/writer I are located so as to correspond to each coil of the C card 2, respectively, so that each coil faces the corresponding coil.

Here, the transmission coil 3a of the power supply system includes coils 3a-1,
The core 14 is divided into two parts 3a-2 and placed inside the core 14.
is the gap 19 into which the core 18 of the IC card 2 is inserted.
The 0-shape formation is a U-shaped core and is integral. That is, as shown in the figure, the receiving coil 3b and core 18 on the IC card 2 side are sandwiched between the transmitting coil 3a and the core 14 with a gap 19 interposed therebetween.

Note that the cores 14 and 18 are made of a material with high magnetic permeability, such as ferrite, permalloy, amorphous iron or an alloy thereof, or the like. Also, its thickness is IC
Inside the card 2, it is approximately 0.5 mm to 5 mm.

In the case of the above configuration, the signal system coils (transmission coil 3 av reception coil 3b) located on the outside can have a large diameter and a large inductance. In particular, it is possible to increase the internal impedance by using a thin wire. the result,
Since the DC resistance value can be set higher than that of the power system coil, the average DC current value during data transmission can be held down by that much, and the power used during data transmission can be reduced.

On the other hand, the power system coil located inside (transmission/reception coil 4
Since the transmitting/receiving coil 4b) has a core arranged inside, sufficient power transmission is possible even with a coil having a small inductance. Therefore, it is possible to reduce the inductance and, in particular, to use a wire with a large diameter to further reduce the direct current resistance.

As a result, wasteful power consumption during power transmission can be reduced, and since a core is used, leakage magnetic flux is also reduced, allowing efficient power transmission.

If the inductance of each coil is selected under these conditions, the coils will be adjacent to each other in the coupled state when the IC card 2 is inserted into the reader/writer 1, forming a closed magnetic path and supplying power. A tightly coupled transformer is formed in the system, and a loosely coupled transformer is formed in the signal system. As a result, as shown in FIG. 3, each transformer has a characteristic such that the attenuation characteristic is minimized at the center frequency ft+f2 depending on the selected inductance. Therefore, the frequency fl can be selected from a range of approximately several tens of kHz to several hundred kHz, and the frequency f2 can be selected to be approximately IMHz in this embodiment, which is the frequency of the signal system. By selecting the frequency that minimizes the attenuation characteristic in this manner, power and data can be transmitted more efficiently.

In addition, in such a case, the power supply system filters 5a, 5
For b, a bandpass filter centered on the frequency fl shown in FIG. 3 is adopted, and for the filters 6a + 8b, a bandpass filter centered on the frequency f2 in the same figure is adopted, and their bands are different, They are kept from overlapping and from interfering with each other.

As described above, the inductance of each coil is selected,
In addition, by selecting the frequency frtfz, it is possible to transmit power and information with high transmission efficiency.

As described above, although the example shows the case where the coil is circular, the shape of the coil is not limited to circular. Further, the inductance can be selected depending on the size of the card.

In the embodiment, an IC card is attached to the writer during the league.
Although a C card transmission/reception system is taken as an example, the present invention can be applied to card-shaped recording media in general, including memory cards, and the device to which it is attached may also be an external device such as a host computer. .

[Effects of the Invention] As can be understood from the above explanation, in this invention, the inductance of the coil itself can be reduced by arranging a power supply coil inside both the external device and the information card. (Since the internal resistance can be reduced, DC power consumption can be reduced.Moreover,
Since a core is provided inside the coil, even if the coil has a small inductance, the overall inductance can be increased when connecting an external device and an information card, and power can be efficiently transmitted through close coupling.

On the other hand, since the transmitting/receiving coils for transmitting and receiving data are both placed outside the power supply coil, their inductance can be increased, and the internal impedance can be increased, allowing the current to flow during transmission in the signal transmission system. can be kept small.

As a result, by reducing the DC power consumed during data transmission, both the power supply system and the signal transmission/reception system can transmit power and information with high power efficiency.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an electromagnetic coupling part in an IC card information processing system according to an embodiment to which the electromagnetically coupled card information processing system of the present invention is applied, and FIG. 2 is a block diagram of the IC card information processing system. , FIG. 3 is an explanatory diagram of frequencies used in the power supply system and signal system and their transmission characteristics. ■...ICC card reader writer 2...IC card, 3a...transmission coil, 3b...
・Receiving coil, 4a+4b... Transmitting/receiving coil, 5a,
5b, 6a, 6b...filter, 7...oscillation circuit,
8... Power supply circuit, 9... Rectifier circuit, 10... Constant voltage circuit, 11.15... Modulation circuit, 12.16...
Demodulation circuit, 13.17... Arithmetic processing circuit, 14.18
···core. Hz

Claims (1)

[Claims] (1) An external device that reads or writes data to an electromagnetically coupled information card, and which is electromagnetically coupled to this external device, receives power from this external device, and exchanges signals with this external device. In an information processing system for an electromagnetically coupled card, the external device has a core with high magnetic permeability and supplies power in the form of magnetic energy to the information card. and a second coil disposed outside the first coil with the first coil inside to exchange data with the information card, and the information card has a high magnetic permeability coil. It has a third coil that has a core and is magnetically coupled to the first coil, and a fourth coil that is arranged outside the third coil and is electromagnetically coupled to the second coil. An information processing system for an electromagnetically coupled card, characterized by: