JP2811679B2 - How to use memory card - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method of using a memory card suitable for use in, for example, recognizing articles in a distribution system, checking entry / exit at a gate, and the like.

[Summary of the Invention]

According to the present invention, in a method of using a memory card having storage means for storing information, by using a capacitor as a power supply of the memory card, it is possible to supply an inexpensive memory card with a simple structure. It is characterized in that the usable time of the memory card is arbitrarily set by controlling the charge amount.

[Conventional technology]

2. Description of the Related Art Conventionally, a memory card formed in the form of a tag (tag) or a card has been used for recognizing articles in a physical distribution system and checking in and out of a person at a gate. Contact memory cards) are often used.

As the non-contact type memory card, a reflection type or an active type is used, and the reflection type memory card is
An antenna for radio wave reflection is provided on the memory card main body, and radio waves transmitted from the recognition device are reflected by the antenna and sent back to the recognition device. In addition, the active memory card is provided with a data generation circuit, a transmission circuit for transmitting data, a reception circuit for receiving radio waves transmitted from the recognition device, and the like, and responds to radio waves from the recognition device. To send data for recognition.

Specific examples of such a non-contact type memory card are disclosed in, for example, JP-A-59-112376, JP-A-62-26591, and JP-A-62-38643 as prior art. I have.

The applicant of the present application has previously proposed a reflection type transmission device applicable to a memory card according to the specification and drawings of Japanese Patent Application No. 63-6292.

That is, the reflection type transmission device includes an antenna that reflects an incident continuous wave radio wave, a transmission data generation circuit, and an impedance change circuit that changes the impedance of the antenna in accordance with the transmission data. The feature is that data is transmitted using the reflection characteristics of the antenna that change according to the change in the impedance of the antenna, and a carrier wave is generated using the reflected wave of the antenna as a radio wave for carrying data. Since it is not necessary to provide a transmission circuit and a power supply for transmission, a data transmission device that operates with extremely low power can be manufactured with a simple circuit configuration.

[Problems to be solved by the invention]

However, the above-mentioned memory card is usually expensive because a battery is used as a power supply, and it is difficult to grasp the battery life, so that a clear usable period of the memory card cannot be known.

In general, the longer the life of a battery used as a power source is, the better. However, there are many memory cards that do not require long-term use depending on the application, and a battery is used for such a so-called short-time memory card. In this case, the purpose of use of the memory card is lost before the battery runs out, and the battery is wasted. Further, when considering the application to an entry / exit card or the like with an expiration date, it is desired to develop a method of using a memory card in which the usable time can be set positively and arbitrarily.

In view of the above-mentioned problems, the present invention has an object to provide a method of using a memory card that can be provided at a low cost by using a capacitor having a simple structure and that can set an available time arbitrarily. It is assumed that.

[Means for solving the problem]

In order to solve the above-mentioned problem, a method of using a memory card according to the present invention is to control a charge amount as a power supply unit in a method of using a memory card including a storage unit that receives power supply from a power supply unit. By using a capacitor whose discharge state can be adjusted, power can be supplied from this capacitor to enable reading of the storage content of the storage means, and by adjusting the charge amount of the capacitor, the storage content of the storage means can be adjusted. It is characterized in that the readable time is set arbitrarily.

[Action]

In the method of using the memory card according to the present invention, it is possible to arbitrarily set the usable time by using a capacitor that is generally simpler and cheaper than a battery as a power source and controlling the charge amount of the capacitor. it can.

〔Example〕

Hereinafter, an embodiment of a method of using a memory card according to the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a main part of a memory card used in an embodiment of the present invention.

In FIG. 1, a capacitor C provided between the diode D and the ground is charged from a charge voltage input terminal 1 via a diode D for backflow prevention by a charger or the like described later. By supplying power from the capacitor C, a RAM (random access memory) as storage means
3 is activated. Then, a data signal is input from a data input / output terminal 2 from a writing means (not shown), and at the same time, a clock signal is input from a clock signal input terminal 4 and data is written into the RAM 3. The data written in the RAM 3 is read out from the data input terminal 2 according to, for example, a clock signal input from the clock signal input terminal 4. Then, the read signal is transmitted to an information recognizing unit (not shown) in a non-contact (wireless) manner via an antenna or in a contact (wire) manner via a terminal.

Next, the charging and discharging relationship of the capacitor C will be described with reference to FIG.

In the second diagram, the voltage charges the T ₁ times the capacitor C and the V ₁ volts, the discharge from the point P, i.e., when starting the power supply to RAM3 shown in FIG. 1, T ₂
Voltage discharge time of -T ₁ it can be seen that the decrease in V ₀ volts. V ₀ volt line indicated by the dotted line in the figure is a minimum operating voltage of the RAM 3. That is, since the RAM 3 has a characteristic that data as stored contents can be read up to the minimum voltage V _{0, the} disk capacitor C supplying power to the RAM 3 is charged for T ₁ time (V ₁ volt). When charging is performed, the data read from the RAM 3 is performed by the capacitor C
Time to drop to a voltage V ₀ volts, that is,
It can be seen that the memory card can be used for T ₂ -T ₁ hour. Therefore, by adjusting the charge amount of the capacitor C, the usable time of the memory card can be positively and arbitrarily set.

The above is an example of charging from the time when the accumulated charge of the capacitor C is 0, but the charge remains in the capacitor C by utilizing the relationship between the capacitor terminal voltage and the discharge time in FIG. Even in the case of charging at the time of reuse, the usable time of the memory card can be positively and arbitrarily set by checking the terminal voltage of the capacitor C.

In other words, in the case of a battery, there is a possibility that the life of the memory card will expire during use of the memory card due to discharge in a storage state or the like. ) By charging, effective use for a predetermined time or more can be guaranteed.

Incidentally, if such a memory card cannot be collected at the card collection place, as described above, T ₂ −T ₁
After time (discharge time), the voltage of the capacitor decreases to V _0, use of the memory card becomes impossible, it will not be exploited.

As means for charging the capacitor C, for example,
A charger as shown in the figure is conceivable.

The charging voltage input terminal 1 of the memory card shown in FIG.
, The charging time is set by the time setting means 13. The charging time is displayed by the display means 14, and at the same time, a charging voltage is applied to the capacitor C in the memory card by the constant voltage circuit 15.

As is clear from the above description, the memory card used in the method of using the memory card according to the present invention can be manufactured at a lower cost than a battery by using a capacitor having a simple structure.

It is desirable to apply such a method of using a memory card when the use time is short, for example,
It is highly effective when applied to such things as entrance tickets for facilities and ID tags in distribution systems.

Next, a second embodiment of the method of using the memory card according to the present invention will be described with reference to FIG.

FIG. 4 is a diagram showing a second embodiment to which the present invention is applied in the reflection type transmission device disclosed in Japanese Patent Application No. 63-6292 previously disclosed by the present applicant.

In FIG. 4, the reflection type transmitting device, which is a memory card, is configured as an ID tag device.

The tag body 21 is formed, for example, in a thin tag shape using a synthetic resin, and has a dipole antenna 22 printed and wired on a flexible substrate or the like provided on the surface. Also,
The contents include an identification code generator 23 that forms oscillation data.
In addition, a capacitor 24 which is a power supply for driving the identification code generator 23 is embedded. As the capacitor 24, for example, an electrolytic double-layer capacitor is used, and a required time is supplied from the charge voltage input terminal 31 via the diode Ds for preventing backflow, for example, by the charger shown in FIG. Have been charged for a minute.

The identification code generator 23 includes an oscillator 25, an address counter 2
6. A one-chip IC in which a PROM (programmable read only memory) 27 as a storage means and an FET transistor 28 are integrated, and power from the capacitor 24 is supplied via a circuit power supply terminal 32. ing. The power consumption is extremely small.

Desired data is written to the PROM 27 by, for example, a writer (not shown).

The positive electrode and the negative electrode of the capacitor 24 are directly connected to terminals 29a and 29b provided on the identification code generator 23, respectively, and the identification code generator 23 is always operating. Therefore, the oscillator 25, the address counter 26, the PROM 27
The data generation circuit 30 is always operating, and a clock signal cK of a predetermined frequency is constantly derived from the oscillator 25 to the address counter 26.

The address counter 26 specifies the address of the PROM 27, and the data written at the specified address is read. The address counter 26 counts up each time the clock signal cK is supplied and specifies the next address, so that the data written in the PROM 27 is read one after another. The read data is given to the gate electrode of the FET transistor 28 as a series of identification codes ID composed of digital signals. For this reason, the potential of the gate electrode changes to a high potential and a low potential in accordance with the data of the identification code ID, so that the FET transistor performs an ON / OFF operation according to the identification code ID.

The FET transistor 28 has a source electrode grounded and a drain electrode connected to the terminal 29a of the identification code generator 23.
It is connected to the. Therefore, the impedance between the terminals 29a and 29b changes when the FET transistor 28 is turned on and off. The antenna 22 is connected to these terminals 29a and 29b.
Feed points 22a and 22b are connected. This reflection type transmission device is provided with a capacitor as in the first embodiment.
The discharge time (usable time) is adjusted by controlling the charge to 24 according to the charge / discharge characteristics of FIG.

 Next, the operation of the reflection type transmission device will be described.

Upon receiving a microwave continuous wave transmission wave 31 radiated from a communicator (not shown), which is a confirmation means,
A voltage is induced in the dipole antenna 22, and a reception current I flows. Therefore, the radio wave received from the dipole antenna 22, that is, the transmission wave 31 radiated from the communicator is re-radiated. The communicator receives the re-radiated radio wave, that is, the reflected wave 32 from the dipole antenna 22, and demodulates it.

Terminals 29a and 29 according to ON / OFF of FET transistor 28
The impedance between the points b (between the feeding points 22a and 22b) changes. When the FET transistor 28 is turned on, the feed point 22a,
The impedance between 22b becomes, for example, 50 [Ω], and the dipole antenna 22 matches the transmission wave 31 of 2.45 [GHz]. When the FET transistor 28 is turned off, the impedance of the feeding points 22a and 22b is, for example, 100 [Ω].
And the matching of the dipole antenna 22 is lost. When matching is achieved, the reflection characteristics of the dipole antenna 22 are different. Therefore, there is a difference in phase and amplitude between the reflected wave 32 when matching is performed and the reflected wave when matching is not performed. In other words, this ID tag device turns on and off the FET transistor 28, modulates the phase of the received radio wave (the transmission wave 31 from the communicator), and reflects it to the communicator. Therefore, the communicator can receive data by receiving the composite wave of the reflected wave 32 and the transmission wave 31 and demodulating the phase or the amplitude.

As described above, the matching state of the dipole antenna 22 and the ON / OFF state of the FET transistor 28 are determined by the identification code ID.
Therefore, the communicator can detect the identification code ID. Therefore, there is no need to create a carrier wave for transmitting the identification code ID to the communicator by the ID tag device, and it is not necessary to provide a transmission circuit and a power supply for transmission.

Therefore, only the identification code generator 23 consumes power, so that power consumption is low. By using a capacitor as the power source, an ID tag device (memory card) that can be produced at low cost can be used. As described in the description of the first embodiment, the capacitor 24 can be used. By adjusting the charge amount of the ID tag device, the usable time of the ID tag device can be arbitrarily set.

Although an electrolytic double layer capacitor is used as the capacitor 24, a paper capacitor or the like may be used, for example. Further, the PROM 27 used as the storage means is, for example, RA
Of course, it may be M (random access memory) or the like.

That is, since the ROM is non-volatile, the written data contents are retained even when the power is turned off, and the ID tag device can be reused only by recharging the capacitor as the power supply. For this reason, for example, it is preferable to apply the present invention to the case where stored data has no secrecy.

On the other hand, since the RAM is volatile, the written data content is lost when the power is turned off, and re-use and re-write are necessary for reuse. Therefore, it is preferable to apply the present invention to, for example, a case where stored data has confidentiality.

The above is to transmit and receive data wirelessly, of the non-contact type memory card, provided with an antenna for radio wave reflection in the memory card body, reflect the radio wave transmitted from the recognition device to the antenna and send it back to the recognition device, so-called, Although the case where a reflection type is used has been described, a data generation circuit,
A so-called active type that includes a transmitting circuit for transmitting data and a receiving circuit for receiving radio waves transmitted from the recognition device, and transmits data for recognition in response to radio waves from the recognition device. It may be applied when using.

Further, the present invention may be applied to a case where a terminal is provided on a memory card and the terminal is brought into contact with a recognition device to transmit data, that is, a so-called contact type is used.

〔The invention's effect〕

In the method of using the memory card according to the present invention, by using a capacitor having a simple configuration as a power supply,
Inexpensive memory cards can be used.

Further, by adjusting the charge amount of the capacitor, the memory card can always be used for a predetermined time or more, and can be positively set to an arbitrary usable time.

In particular, when applied to a case where a memory card having a short usable time is used, the effect is large.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main part of a memory card used in a first embodiment according to the present invention, and FIG. 2 explains characteristics of a capacitor used in a memory card used in the present invention. FIG. 3 is a block diagram showing a charger, and FIG. 4 is a block diagram showing a memory card used in a second embodiment according to the present invention. DESCRIPTION OF SYMBOLS 1 ... Charge voltage input terminal 2 ... Data input / output terminal 3 ... RAM (random access memory) 4 ... Clock signal input terminal 22 ... Dipole antenna 23 ... Identification code generator 24 ... Double layer electrolytic capacitor 27 …… PROM (Programmable Read Only Memory) 28 …… FET transistor 31 …… Transmitted wave 32 …… Reflected wave

Claims (1)

(57) [Claims] 1. A method of using a memory card having a storage means for receiving power supply from a power supply means, wherein the power supply means comprises a capacitor whose discharge state can be adjusted by controlling a charge amount. The power supply from the storage means enables reading of the storage content of the storage means, and by adjusting the amount of charge of the capacitor, the time during which the storage content of the storage means can be read is arbitrarily set. How to use a memory card.