JPH0258191A - Memory card - Google Patents

Abstract

PURPOSE:To supply an inexpensive memory card with a simple structure and to arbitrarily set the time when it can be used by using a capacitor as the power source of the memory card. CONSTITUTION:A capacitor C is charged from a charge voltage input terminal 1 through a reverse current preventing diode D. A RAM (random access memory) 3 is set to the operating state by power supply from the capacitor C. A clock signal is inputted from a clock signal input terminal 4 simultaneously with input of a data signal from a writing means through a data input/output terminal 2 and data is written in the RAM 3. Data written in the RAM 3 is read out from said data input terminal 2 in accordance with the clock signal inputted from the clock signal input terminal 4. Thus, the capacitor C whose structure is simpler than a battery and which is more inexpensive than the battery is used, and charging of this capacitor C is controlled to arbitrarily set the time when the memory card can be used.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applicable to, for example, recognition of articles in a logistics system,
This invention relates to a good memory card that can be used to check people who have left the gate at the gate.

[Summary of the invention]

The present invention provides a memory card having a storage means for storing information, and by using a capacitor as the power source of the memory card, it is possible to provide a memory card with a simple structure and low cost, and the charging of this capacitor is also possible. The feature is that the usable time of the memory card can be arbitrarily set by controlling the memory card.

[Conventional technology]

Conventionally, memory cards shaped like tags or cards have been used to recognize goods in logistics systems and check people entering and exiting at gates. Non-contact memory cards are commonly used.

The non-contact memory cards mentioned above are either reflective or active. Reflective memory cards have an antenna for reflecting radio waves on the memory card body, and reflect radio waves transmitted from the recognition device. The signal is reflected by the antenna and sent back to the recognition device. In addition, active memory cards are equipped with a data generation circuit, a transmission circuit for transmitting data, a reception circuit for receiving radio waves transmitted from the recognition device, etc. It is possible to send recognition data in response to the

Specific examples of such non-contact type memory cards are disclosed in, for example, Japanese Patent Laid-Open Nos. 59-112376 and 62-26.
This method is disclosed as prior art in Japanese Patent Application No. 591 and Japanese Patent Application Laid-Open No. 62-38643.

The applicant of the present invention has also previously proposed a reflective transmitter that can be used in memory cards, based on the specification and drawings of Japanese Patent Application No. 63-6292.

In other words, this reflective transmitter includes an antenna that reflects incident continuous wave radio waves, a transmission data generation circuit,
and an impedance changing circuit that changes the impedance of the antenna in accordance with the transmission data, and transmits data by utilizing the fact that the reflection characteristics of the antenna change in accordance with the change in the impedance of the antenna. This method utilizes reflected waves from antennas as radio waves for transmitting data, and there is no need to provide a transmitting circuit to generate carrier waves or a transmitting power supply, so a data transmitting device that operates with extremely low power can be constructed using a simple circuit. It can be manufactured with the following configurations.

[Problem to be solved by the invention]

However, since the above-mentioned memory cards usually use batteries as a power source, they are expensive, and it is difficult to know the battery life, so it is not clear how long the memory card can be used.

Additionally, the longer the lifespan of batteries used as a power source, the better, but depending on the purpose, there are many memory cards that do not require long-term use, so batteries are used for short-term use. Otherwise, the purpose of using the memory card will be lost before the battery runs out, and the battery will be wasted. Furthermore, when considering application to entry/exit inspections with expiration dates, it is desired to develop a memory card whose usable time can be proactively and quickly set.

Therefore, in view of the above-mentioned problems, the present invention aims to provide a memory card which can be provided at low cost by using a capacitor with a simple structure, and which can arbitrarily set the usable time. be.

[Means to solve the problem]

In order to solve the above-mentioned problems, a memory card according to the present invention is a memory cart comprising a power supply means and a means for receiving power supply from the power supply means. The present invention is characterized by using a capacitor whose discharge state can be adjusted by controlling charging, and by supplying power from the acid capacitor, it is possible to read out the stored contents of the storage means.

[For production]

The memory card according to the present invention uses a capacitor, which is generally simpler in structure and cheaper than a battery, as a power source, and by controlling the charging of this capacitor, the usable time can be arbitrarily set.

〔Example〕

Embodiments of the memory card according to the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the main parts of a memory card according to an embodiment of the present invention.

In FIG. 1, a capacitor C provided between the diode D and ground is charged from a charge voltage input terminal 1 via a reverse current prevention diode D using a charger or the like to be described later. By supplying power from the capacitor C, the RAM (Random Access Memory) 3, which is the recording means, is activated. And data input/output terminal 2
At the same time that a data signal is inputted from a writing means (not shown), a clock signal is inputted from the 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 in response to a clock signal input from the clock signal input terminal 4, for example. Then, this read signal is sent to an information recognition means (not shown) via an antenna in a non-contact (wireless) manner, or via a terminal (contact (wireless)).
wired) transmitted.

Next, the charging/discharging relationship of the capacitor C will be explained using FIG. 2.

In Fig. 2, capacitor C is charged for T1 hours to bring the voltage to ■1 port, and at this point P, discharge is started, that is, power supply to RAM3 shown in Fig. 1 is started, T2 - T. It can be seen that the voltage drops to Vo volts over the discharge time. The Vo volt line indicated by a dotted line in this figure is the lowest voltage at which the RAM 3 can operate. That is, R.A.
Since M3 has the characteristic that it is possible to read the stored data up to the lowest voltage VO, the above RA
If the capacitor C that supplies power to M3 is charged for T1 hours (■□ volts), data in the RAM 3 can be read out until the voltage of the capacitor C drops to ■o volts. In other words, it is possible to use the memory card for T2-'ri time. Therefore, by adjusting the charging of the capacitor C, the usable time of the memory card can be positively and quickly set.

The above is an example of charging the capacitor C while the accumulated charge is 0. However, by using the relationship between the capacitor terminal voltage and the discharging time shown in Fig. 2 above, the capacitor C
Even in the case of charging for reuse, in which charge remains in the memory card, the usable time of the memory card can be positively and arbitrarily set by looking at the terminal voltage of the capacitor C.

In other words, in the case of batteries, due to discharge etc. during storage,
While a memory card is in use, there is a risk that it will reach the end of its lifespan and become unusable, but by using a capacitor and charging the memory card (only as much as necessary) immediately before use, it is guaranteed that it can be used effectively for more than the specified time. can do.

If you are unable to collect such a memory card at a card collection location, please contact 72-7 as mentioned above.
After one hour (discharging time), the capacitor voltage will drop to Va, making it impossible to use the memory card.
It will not be misused.

As a means for charging the capacitor C, for example, a charger as shown in FIG. 3 can be used.

Set the charging voltage input terminal 1 of the memory card shown in FIG. 1 to the charging terminal 11 of this charger, and
2, the charging time is set by the time setting means 13. This charging time is displayed on the display means 14, and at the same time, a constant voltage circuit 15 applies a charging voltage to the capacitor C in the memory card.

As is clear from the above description, by using a capacitor with a simple structure, it can be manufactured at a lower cost than a battery.

It is desirable that such a memory card be applied to something that can be used for a short period of time, and it is highly effective to apply it to things such as admission tickets for facilities, ID tags in logistics systems, etc., for example.

Next, a second embodiment of the memory card according to the present invention will be described using FIG. 4.

Figure 4 is Japanese Patent Application No. 636292, which was previously disclosed by the applicant.
FIG. 3 is a diagram showing a second embodiment in which the present invention is applied to a reflection type transmitter of the No.

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

The tag body 21 is made of, for example, synthetic resin and is formed into a thin thank-you note, and has a dipole antenna 22 printed and wired on a flexible substrate or the like on its surface. Furthermore, an identification code generator 23 that forms oscillation data and a capacitor 24 that is a power source for driving the identification code generator 23 are embedded inside. This capacitor 24
For example, an electrolytic 2VFIM capacitor is used, and the battery is charged for the necessary time from the charge voltage input terminal 31 via the reverse current prevention diode Ds by, for example, the charger shown in FIG. has been done.

The identification code generator 23 is composed of a one-chip IC in which an oscillator 25, an address counter 26, a FROM (programmable read only memory) 27 serving as a storage means, and a FET transistor 28 are integrated.
The power from the capacitor 24 is supplied to the circuit power supply terminal 32.
Supplied via. Note that power consumption is extremely small.

The PROM 27 has a writing device (not shown), for example.
Desired data is written using the above steps.

Terminals 29a, 2 provided on the identification code generator 23
The positive and negative electrodes of the capacitor 24 are directly connected to the terminal 9b, and the identification code generator 23 is always in operation. Therefore, the data generation circuit 30 consisting of the oscillator 25, the address counter 26, and the PROM 27 is always operating, and a clock signal ck of a predetermined frequency is always derived from the oscillator 25 to the address counter 26.

The address counter 26 defines the address of the PROM 27 as t, and the data written at the designated address is read out. Since the address counter 26 counts up and specifies the next address every time the clock signal ck is applied, the data written in the PROM 27 is read out one after another. The read data is
PI as a series of identification code ID consisting of digital signals
It is applied to the gate electrode of the F, T transistor 28. Therefore, the potential of the gate electrode changes to a high potential or a low potential according to the data of the identification code ID, so that the FETl-transistor 28 performs on/off operations 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. Therefore, as the FET transistor 28 turns on and off, the terminals 29a and 2
9b changes. This terminal 29
Feeding points 22a and 22b of the antenna 22 are connected to a and 29b.

As in the first embodiment described above, this reflection type transmitter controls the charging of the capacitor 24 according to the charging and discharging characteristics shown in FIG.
are being adjusted.

Next, the operation of this reflective transmitter will be explained.

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

Terminal 29 depending on whether the FET transistor 28 is turned on or off.
The impedance between a and 29b (between the feeding points 22a and 22b) changes. When the FET transistor 28 is turned on, the impedance between the feeding points 22a and 22b becomes, for example, 50 (Ω), and the dipole antenna 22 becomes 2.
45 (GHz) transmission wave 31. Also,
When the FET transistor 28 is turned off, the feed point 22
The impedance of a and 22b becomes, for example, 100 (Ω), and the matching of the dipole antenna 22 is broken.When the matching is not achieved, the reflection characteristics of the dipole antenna 22 are different.For this reason, the reflected wave 32 when matched is There is a difference in phase and amplitude between the reflected wave and the unmatched reflected wave.In other words, this ID
The tag device turns on and off the FET transistor 28 to transmit the received electric eL (transmission wave 31 from the communicator).
This means that the signal is phase (or amplitude) modulated and reflected to the communicator. Therefore, in the communicator,
Data can be received by receiving a composite wave of the reflected wave 32 and the transmitted wave 31 and demodulating the phase or amplitude.

As described above, since the matching state of the dipole antenna 22 and the on/off state of the FET transistor 28 correspond to the identification code ID, the identification code ID can be detected by the communicator. Therefore, the identification code I
Since there is no need to create a carrier wave (carrier) for transmitting D to the communicator using the ID tag device, there is no need to provide a transmitting circuit and a power source for transmitting.

Therefore, since only the identification code generator 23 consumes power, the power consumption is small. By using a capacitor as this power source, an ID tag device (memory card) can be manufactured at low cost, and as described in the explanation of the first embodiment, by adjusting the charging of the capacitor 24, , the usable time of this 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. Furthermore, it goes without saying that the PROM 27 used as the storage means may be replaced by, for example, a RAM (random access memory).

That is, in the case of ROM, since it is non-volatile, the written data contents are retained even if the power is turned off, and the ID tag device can be reused simply by recharging the capacitor that is the power source. For this reason, for example, it is preferable that the stored data be used even if the data is not confidential.

On the other hand, since RAM is volatile, the written data content is lost when the power is turned off, and recharging and rewriting are required for reuse. For this reason, it is preferable to apply this method to, for example, data that is stored in a confidential manner.

The above is a so-called contactless memory card that transmits and receives data wirelessly, in which a radio wave reflecting antenna is provided on the memory card body, and the radio waves transmitted from the recognition device are reflected by the antenna and sent back to the recognition device. We have explained what is called a reflective type memory card, which is also a non-contact type memory card and is equipped with a data generation circuit, a transmission circuit for transmitting data, and a reception circuit for receiving radio waves transmitted from a recognition device. However, it may also be applicable to a so-called active type device that sends recognition data in response to radio waves from a recognition device.

Furthermore, the present invention may be applied to a so-called contact type device in which the memory card has a terminal and data is transmitted by bringing the terminal into contact with a recognition device.

[Effects of the Invention] The memory card according to the present invention can be manufactured at low cost by using a capacitor with a simple configuration as a power source.

Also, by adjusting the amount of charge of this capacitor,
The memory card can always be used for a predetermined period of time or more, and can also be actively set to any usable period.

This is particularly effective when used for memory cards that are used for a short period of time.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the main parts of a memory card as a first embodiment of the present invention, and FIG. 2 is a diagram for explaining the characteristics of a capacitor used in the memory card of the present invention. , FIG. 3 is a block diagram showing a charger, and FIG. 4 is a block diagram showing a second embodiment of the present invention. 1... Charge voltage input terminal 2... Data input/output terminal 3... RAM (random access memory) 4...
・Clock signal input terminal Dipole antenna Identification code generator Double layer electrolytic capacitor FROM (Programmable Read Only Memory) 28...FET) Transistor 31...Transmitted wave 32...Reflected wave

Claims (1)

[Scope of Claims] A memory card comprising a power supply means and a storage means receiving power supply from the power supply means, wherein the power supply means is a capacitor whose discharge state can be adjusted by controlling charging. 1. A memory card characterized in that the storage contents of the storage means can be read out by supplying power from the capacitor.