JP2009003785A - Removable media for data transfer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent data leakage by automatically erasing data temporarily stored in a storage device when transferring data between different PCs. <P>SOLUTION: Removable media for data transfer which have a terminal group 13 connectable to external devices and are used for data transfer between different external devices includes: a non-volatile storage device 11 which is connected to the terminal group 13 and holds data; a data erasing circuit 21 which erases all of data stored in the non-volatile storage device 11; a power source circuit 22 which stores power for driving the data erasing circuit 12; and a switch circuit 23 which turns on/off power supply from the power source circuit 22 to the data erasing circuit 21. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a data transfer removable medium for transferring a large amount of data between different external devices, and more particularly to a data transfer removable medium having a function of erasing stored contents. The present invention also relates to a removable media converter that provides a general-purpose nonvolatile removable media with a function of erasing the stored contents.

  Large-capacity removable media represented by USB memory and SD memory card are compact and are often used for transferring large amounts of data, but accidents such as loss are likely to occur due to their high portability. In this case, the loss or loss of stored data is a greater problem than the loss of media itself. Some media use the encryption function together to reduce the risk of information leakage. However, as long as the data exists on the media, it cannot be completely prevented.

If only data transfer is taken into account, once data is transferred from a PC (personal computer) to media and then transferred to another PC, etc., if the user erases the data on the media, information leakage due to media loss The risk of disappearing. However, this measure has the potential for human error. In addition, a USB memory or the like having a fingerprint authentication function is also on the market, but it is impossible to completely prevent leakage as long as data physically exists.
JP 2007-115103 A

  The present invention has been made in consideration of the above circumstances, and its object is to automatically delete data stored in a storage device when transferring data between different PCs. An object of the present invention is to provide a removable medium for data transfer capable of preventing leakage.

  In order to solve the above problems, the present invention adopts the following configuration.

  That is, one embodiment of the present invention is a removable medium for data transfer that has a terminal group that can be connected to an external device and that transfers data between different external devices, and is connected to the terminal group. A non-volatile storage device for holding; a data erasing circuit for erasing all data stored in the non-volatile storage device; a power supply circuit for storing power for driving the data erasing circuit; and And a switch circuit for switching between an on state in which power is supplied to the data erasing circuit and an off state in which power is not supplied.

  Another aspect of the present invention is a data transfer removable medium for transferring data between different external devices having a terminal group connectable to an external device, which is connected to the terminal group, A volatile storage device for holding data; a power supply circuit for storing power for maintaining data stored in the volatile storage device; and an on state for supplying power from the power supply circuit to the volatile storage device And a switch circuit for switching an off state in which power is not supplied.

  Still another aspect of the present invention includes a first terminal group connectable to a nonvolatile removable medium and a second terminal group connectable to an external device, and the nonvolatile removable medium is used for data transfer. A removable media converter for providing an interface circuit, which is inserted between the first terminal group and the second terminal group, and connects the nonvolatile removable medium and the external device; A data erasing circuit connected to the non-volatile removable media via the first terminal group, for erasing all the data of the removable media, a power supply circuit for storing power for driving the data erasing circuit, and the power source Switch circuit for switching between an on state supplying power to the data erasing circuit and an off state not supplying power , Characterized by comprising a.

  According to the present invention, a data erasure circuit for erasing all data stored in a nonvolatile storage device is provided, and after the data is transferred, the data is forcibly erased by this circuit, thereby achieving the purpose of data transfer. The memory contents can be automatically deleted after the achievement. Further, by stopping the power supply to the volatile storage device after the data transfer, the stored contents can be automatically deleted after the purpose of the data transfer is achieved.

  Therefore, when data is transferred between different PCs, the data stored in the storage device can be automatically deleted, and data leakage can be prevented.

  The details of the present invention will be described below with reference to the illustrated embodiments.

(First embodiment)
FIG. 1 is a circuit configuration diagram showing an outline of a removable medium for data transfer according to the first embodiment of the present invention.

  The present embodiment is used as a so-called USB memory connected to a USB terminal of a PC, and uses a nonvolatile storage device such as an electrically rewritable EEPROM as the memory.

  A NAND flash memory cell 11 and a memory controller 12 as a non-volatile storage device are accommodated in the housing 10. The memory controller 12 controls data writing, reading, erasing and the like of the flash memory cell 11 and is connected to the terminal group 13. The terminal group 13 is inserted and connected to a USB terminal of a PC, and is composed of four terminals: a power supply terminal, a ground terminal, and two differential signal terminals.

  The basic configuration so far is the same as that of a general USB memory. In this embodiment, in addition to these, an erasing circuit 21, a capacitor (power supply circuit) 22, and a switch circuit 23 are provided.

  The erase circuit 21 is the same as a normal flash memory cell erase circuit, and erases all data stored in the flash memory cell 11 at once. The capacitor 22 functions as a power source for driving the erasing circuit 21, and is charged by being supplied with Vcc from the terminal group 13 while being connected to the PC.

  The switch circuit 23 is inserted between the erasing circuit 21 and the capacitor 22 and turns on / off the power supply to the erasing circuit 21. The switch circuit 23 is turned off when the terminal group 13 is connected to the PC, and is turned on when the terminal group 13 is disconnected from the PC. However, even if it is disconnected from the PC, it is turned off while the user is explicitly operating.

  As a specific configuration example of the switch circuit 23, for example, a serial connection of two switches 23a and 23b can be considered as shown in FIG. The first switch 23a is turned off when the terminal group 13 is inserted and connected to the USB terminal of the PC, and turned on when the terminal group 13 is removed from the PC. For example, a mechanical slide switch is used. it can. The second switch 23b is a normally closed push button switch that is turned off only while being pressed by the user.

  As shown in FIG. 3, the push button switch 23b is provided so that the pressing portion is located at the center of the casing 10 of the data transfer removable medium, and the user is holding the data transfer removable medium. Try to hit your finger. As a result, the user does not need to be aware of it, and the switch 23b is turned off as long as the user holds the removable medium for data transfer.

  Next, a method of using the data transfer removable medium according to the present embodiment will be described.

  First, when the terminal group 13 is inserted and connected to the USB terminal of the first PC that is the data transfer source, the switch circuit 23 is turned off and no power is supplied to the erasing circuit 21. In this state, it is possible to supply power to the flash memory cell 11 and the capacitor 22 and to write / read data to / from the flash memory cell 11. Therefore, the flash memory cell 11 operates in the same manner as a normal USB memory. In this state, necessary data in the first PC is read and written to the flash memory cell 11.

  Next, when the terminal group 13 is pulled out from the USB terminal of the first PC in this state, the switch circuit 23 is turned on, and the erasing circuit 21 is driven by the charge stored in the capacitor 22, so that the flash memory cell 11 All stored data is erased.

  Here, when the user pulls out the terminal group 13 from the USB terminal of the first PC while the switch 23b provided on the housing 10 is pressed, the switch circuit 23 is turned off. The data stored in the flash memory cell 11 is not erased without being supplied. If the terminal group 13 is inserted and connected to the USB terminal of the second PC as the data transfer destination while maintaining this state, the switch 23a is turned off. For this reason, even if the user releases the pressing of the switch 23b, power is not supplied to the erasing circuit 21, and the data stored in the flash memory cell 11 is not erased.

  In this state, the data stored in the flash memory cell 11 is copied to the second PC side. When the copying is completed, the switch 23a is turned on by pulling out the terminal group 13 from the USB terminal of the second PC. At this time, if the switch 23b is not positively pressed, the switch 23b is also on, so that power is supplied to the erasing circuit 21 and the data stored in the flash memory cell 11 is completely erased. That is, when the data migration is completed, the data in the flash memory cell 11 is automatically erased.

  As described above, according to the present embodiment, the data erasing circuit 21 for erasing all the data stored in the flash memory cell 11 is provided, and the data is forcibly erased by the circuit 21 after the data is transferred. The stored contents can be automatically deleted after the purpose of data transfer is achieved. Therefore, when the application is limited to data transfer, it is possible to operate without leaving data on the medium, and the risk of information leakage is eliminated.

  Further, when the user moves the medium between the PCs, the user only has to press the switch 23b and does not require a complicated operation. Furthermore, since the data stored in the flash memory cell 11 is automatically deleted when the user releases the medium, there is no inconvenience such as accidentally leaving data in the medium, and information leakage is surely prevented. Can do.

(Second Embodiment)
FIG. 4 is a circuit configuration diagram showing an outline of a removable medium for data transfer according to the second embodiment of the present invention.

  The present embodiment is used as a so-called USB memory connected to a USB terminal of a PC, and uses a volatile storage device such as a DRAM as the memory.

  A DRAM cell 31 and a memory controller 32 as volatile storage devices are accommodated in the housing 30. The memory controller 32 controls data writing, reading, erasing and the like of the DRAM cell 31 and is connected to the terminal group 33. Similarly to the first embodiment, the terminal group 33 is inserted into and connected to a USB terminal of a PC, and includes a power terminal, a ground terminal, and four signal terminals.

  In addition, a capacitor 42 and a switch circuit 43 as a power supply circuit are provided in the housing 30. The capacitor 42 functions as a power source for holding data in the DRAM cell 31 and is charged by being supplied with Vcc from the terminal group 33 while being connected to the PC.

  The switch circuit 43 is inserted between the Vcc terminal of the terminal group 33 and the capacitor 42 and turns on / off the power supply from the capacitor 42 to the DRAM cell 31. The switch circuit 43 is turned on when the terminal group 33 is connected to the USB terminal of the PC, and is turned off when the terminal group 33 is disconnected from the USB terminal of the PC. However, even if it is disconnected from the PC, it remains on while the user is explicitly operating.

  As a specific configuration example of the switch circuit 43, for example, a parallel connection of two switches 43a and 43b can be considered as shown in FIG. The first switch 43a is turned on when the terminal group 33 is inserted and connected to the USB terminal of the PC, and turned off when the terminal group 33 is removed from the PC. For example, a mechanical slide switch is used. it can. The second switch 43b is a normally open push button switch that is turned on only while the user is pressing.

  Next, a method of using the data transfer removable medium according to the present embodiment will be described.

  First, when the terminal group 33 is inserted and connected to the USB terminal of the first PC, the switch circuit 43 is turned on. In this state, power can be supplied to the DRAM cell 31 and the capacitor 42, and data can be written / read to / from the DRAM cell 41. In this state, necessary data in the first PC is read and written in the DRAM cell 31.

  Next, when the terminal group 33 is pulled out from the USB terminal of the first PC in this state, the switch circuit 43 is turned off, and power supply to the DRAM cell 31 is lost, so that data stored in the DRAM cell 31 is stored. Everything is erased.

  Here, when the user pulls out the terminal group 33 from the USB terminal of the first PC in a state where the switch 43b provided on the housing 30 is pressed, the switch circuit 43 is turned on, so that the capacitor 42 is stored. Charge is supplied to the DRAM cell 31, and the stored data in the DRAM cell 31 is not erased. If the terminal group 33 is inserted and connected to the USB terminal of the second PC while maintaining this state, power is supplied to the DRAM cell 31 from the terminal group 33. For this reason, even if the user releases the pressing of the switch 43b, power is supplied to the DRAM cell 31 from the PC side, and the stored data in the DRAM cell 31 is not erased. Further, since the switch 43a is turned on by inserting the terminal group 33 into the USB terminal, the capacitor 42 is charged.

  In this state, the data stored in the DRAM cell 31 is copied to the second PC side. When the copying is completed, the switch 43a is turned off by pulling out the housing 30 from the second PC. At this time, unless the switch 43b is positively pressed, the switch 43b is also turned off, so that the power supply to the DRAM cell 31 is stopped, and the stored data in the DRAM cell 31 is completely erased. That is, when the data transfer is completed, the data in the DRAM cell 31 is automatically erased.

  As described above, according to this embodiment, the switch circuit 43 is provided so that the power can be supplied to the DRAM cell 31 only when the PC is shifted to another PC. Data can be erased automatically. Therefore, after the purpose of data transfer is achieved, the stored contents can be automatically deleted, and the same effect as in the first embodiment can be obtained.

(Third embodiment)
FIG. 6 is a circuit configuration diagram showing an outline of a removable media converter according to the third embodiment of the present invention. In addition, the same code | symbol is attached | subjected to FIG. 1 and an identical part, and the detailed description is abbreviate | omitted.

  In this embodiment, a general USB memory has a function of erasing stored contents, and is connected to a USB terminal of a PC with the USB memory mounted.

  In the housing 50, a first terminal group 51 connected to the USB memory 60 and a second terminal group 52 connected to the USB terminal of the PC are provided. A terminal group 51 connected to the removable medium 60 is the same as a USB terminal provided in a normal PC. The terminal group 52 is the same as the terminal used for a normal USB memory.

  An interface circuit (I / F) 53 is provided between the terminal groups 51 and 52. This I / F 53 is normally configured to bypass the exchange of data between the removable medium 60 and the PC as it is. Similarly to the first embodiment, an erasing circuit 21, a capacitor 22 as a power supply circuit, and a switch circuit 23 are provided.

  The capacitor 22 is connected between the Vcc terminal and the ground terminal of the terminal group 52, and is charged while being connected to the PC. Unlike a normal flash memory cell erase circuit, the erase circuit 21 supplies a flash memory cell initialization signal to the signal terminal of the USB memory 60.

  The switch circuit 23 is connected between the erasing circuit 21 and the capacitor 22 and turns on / off the power supply to the erasing circuit 21. The switch circuit 23 is turned off when the terminal group 52 is connected to the PC, and is turned on when the terminal group 52 is disconnected from the PC. However, even if it is disconnected from the PC, it is turned off while the user is explicitly operating. As a specific configuration example of the switch circuit 23, the configuration shown in FIG. 2 can be used.

  Next, a method for using the removable media converter of the present embodiment will be described.

  First, a normal USB memory 60 is set in this apparatus, and this is used as a removable medium for data transfer. That is, the terminals of the USB memory 60 are connected to the terminal group 51 provided in the housing 50.

  When the terminal group 52 is inserted and connected to the USB terminal of the first PC with the USB memory 60 attached, the switch circuit 23 is turned off and no power is supplied to the erasing circuit 21. In this state, the I / F 53 is in a bypass state, and the USB memory 60 operates as usual. At this time, the capacitor 22 is charged. In this state, necessary data in the first PC is read and written in the USB memory 60.

  Next, when the terminal group 52 is pulled out from the USB terminal of the first PC in this state, the switch circuit 23 is turned on, the erase circuit 21 is driven by the charge stored in the capacitor 22, and the USB memory 60 is initialized. A signal is sent out, and all data stored in the USB memory 60 is thereby erased.

  Here, if the user pulls out the switch 23b provided on the housing 50 in a pressed state, the switch circuit 23 is turned off, so that no power is supplied to the erasing circuit 21 and the data stored in the USB memory 60 is erased. Never happen. If it is inserted into the USB terminal of the second PC while maintaining this state, the switch 23a is turned off. For this reason, even if the user releases the pressing of the switch 23b, the power is not supplied to the erasing circuit 21, and the data stored in the USB memory 60 is not erased.

  In this state, the data stored in the USB memory 60 is copied to the second PC side. When the copying is completed, the casing 50 is pulled out from the second PC, whereby the switch circuit 23 is turned on, the power is supplied to the erasing circuit 21, and the USB memory 60 is completely erased. That is, when the data migration is completed, the data in the USB memory 60 is automatically deleted.

  As described above, according to the present embodiment, the data stored in the USB memory 60 can be automatically deleted after the purpose of data transfer is achieved while using the normal USB memory 60. Therefore, when the application is limited to data transfer, it is possible to operate without leaving data on the medium, and the risk of information leakage is eliminated.

(Modification)
The present invention is not limited to the above-described embodiments. In the embodiment, the capacitor is used as the power supply circuit, but the present invention is not necessarily limited thereto. Any power supply circuit may be used as long as it can supply power to the memory cells and the memory controller for a certain period of time, and a battery can be used.

  As a nonvolatile memory device, not only a NAND flash memory cell but also an OR flash memory cell or a NOR flash memory cell can be used. Further, FeRAM (Ferroelectric RAM) using a ferroelectric capacitor and MRAM (Magnetic RAM) for storing data by magnetism can be used. Furthermore, as a volatile storage device, not only DRAM but also SRAM can be used.

  The configuration of the switch circuit is not limited to that shown in FIGS. 2 and 5 and can be changed as appropriate according to the specifications. Further, a timer function can be added to the switch circuit. Specifically, the first and third embodiments may be configured to be turned on after a predetermined time after disconnecting from the PC and to drive the erase circuit. Further, in the second embodiment, the power supply to the memory cell may be stopped after a certain time after disconnecting from the PC.

  In the embodiment, the USB memory has been described as an example, but the present invention can be applied to a CF card, an SD memory card, and other various removable media. In short, the present invention can be implemented with various modifications without departing from the gist thereof.

1 is a circuit configuration diagram showing an outline of a removable medium for data transfer according to a first embodiment. The circuit block diagram which shows the specific example of the switch circuit used for 1st Embodiment. 1 is a perspective view showing an external configuration of a data transfer removable medium according to a first embodiment. The circuit block diagram which shows the outline of the removable medium for data transfer concerning 2nd Embodiment. The circuit block diagram which shows the specific example of the switch circuit used for 2nd Embodiment. The circuit block diagram which shows the outline of the converter for removable media concerning 3rd Embodiment.

Explanation of symbols

10 ... Case 11 ... Flash memory cell (nonvolatile storage device)
DESCRIPTION OF SYMBOLS 12 ... Memory controller 13 ... Terminal group 21 ... Erase circuit 22 ... Capacitor (power supply circuit)
DESCRIPTION OF SYMBOLS 23 ... Switch circuit 23a ... 1st switch 23b ... 2nd switch 30 ... Housing 31 ... DRAM (volatile storage device)
32 ... Memory controller 33 ... Terminal group 43 ... Switch circuit 43a ... First switch 43b ... Second switch 50 ... Housing 51, 52 ... Terminal group 53 ... Interface circuit 60 ... USB memory

Claims (16)

A group of terminals that can be connected to external devices;
A non-volatile storage device connected to the terminal group for holding data;
A data erasure circuit for erasing all data stored in the nonvolatile storage device;
A power supply circuit for storing electric power for driving the data erasing circuit;
A switch circuit for switching between an on state in which power is supplied from the power supply circuit to the data erasing circuit and an off state in which power is not supplied;
A removable medium for transferring data, comprising:   The switch circuit is in an off state when the terminal group is connected to the external device, and in a state where the terminal group is disconnected from the external device, the switch circuit is in an off state while the user operates the switch circuit in the off state. The removable medium for data transfer according to claim 1, wherein the data transfer removable medium is turned on while the user does not perform an operation.   The switch circuit includes a first switch that is turned off when the terminal group is connected to the external device and turned on when the terminal group is disconnected from the external device, and is turned off only while the user is pressing. 3. The removable medium for data transfer according to claim 2, wherein a push button type second switch to be in a state is connected in series.   2. The data transfer device according to claim 1, wherein the switch circuit is turned off when the terminal group is connected to the external device, and turned on when a predetermined time elapses after being disconnected from the external device. Removable media.   2. The removable medium for data transfer according to claim 1, wherein the nonvolatile storage device is an electrically rewritable EEPROM. A group of terminals that can be connected to external devices;
A volatile storage device connected to the terminal group for holding data;
A power supply circuit for storing power for maintaining data stored in the volatile storage device;
A switch circuit for switching between an on state for supplying power from the power supply circuit to the volatile storage device and an off state for not supplying power;
A removable medium for transferring data, comprising:   The switch circuit is in an on state when the terminal group is connected to the external device, and is in an on state while the user is operating in a state where the terminal group is disconnected from the external device, and is not operated by the user. 7. The removable medium for data transfer according to claim 6, wherein the state is turned off.   The switch circuit is on while the terminal group is connected to the external device and turned off when the terminal group is disconnected from the external device. 7. The removable medium for data transfer according to claim 6, wherein a push button type second switch to be in a state is connected in parallel.   7. The data transfer device according to claim 6, wherein the switch circuit is turned on when the terminal group is connected to the external device, and is turned off after a lapse of a predetermined time after being disconnected from the external device. Removable media.   The removable medium for data transfer according to claim 6, wherein the volatile storage device is a DRAM or an SRAM.   8. The removable medium for transferring data according to claim 1, wherein the power supply circuit is a capacitor and is charged while the terminal group is connected to the external device. A removable media converter having a first terminal group connectable to a non-volatile removable medium and a second terminal group connectable to an external device, for providing the non-volatile removable medium for data transfer,
An interface circuit inserted between the first terminal group and the second terminal group for connecting the nonvolatile removable medium and the external device;
A data erasure circuit connected to the non-volatile removable media via the first terminal group, and erasing all data of the removable media;
A power supply circuit for storing electric power for driving the data erasing circuit;
A switch circuit for switching between an on state for supplying power from the power supply circuit to the data erasure circuit and an off state for not supplying power;
A removable media converter characterized by comprising:   The switch circuit is turned off when the second terminal group is connected to the external device, and is turned off while the user is operating when the second terminal group is disconnected from the external device. 13. The removable media converter according to claim 12, wherein the converter is in an on state while not being used.   The switch circuit is pressed by a user and a first switch that is turned off when the second terminal group is connected to the external device and turned on when the second terminal group is disconnected from the external device. 14. The converter for removable media according to claim 13, wherein a push button type second switch that is in an OFF state is connected in series.   13. The switch circuit according to claim 12, wherein the switch circuit is turned off when the second terminal group is connected to the external device, and is turned on after a predetermined time has elapsed after being disconnected from the external device. Converter for removable media.   13. The converter for removable media according to claim 12, wherein the power supply circuit is a capacitor and is charged in a state where the second terminal group is connected to the external device.

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