JPS63124152A - Memory device - Google Patents

Abstract

PURPOSE:To improve the holding properties of secrecy with a memory device by adding a semiconductor logic circuit having input of a cipher control program, a battery serving as a power supply of said logic circuit, an EEPROM, etc., to a memory card in a unified or composite form. CONSTITUTION:A memory device (card) contains two 16k-bit EEPROM 1, a logic circuit LSI 2 and a fully solid state thin film lithium secondary battery 3 which serves as a power supply of the LSI 2. A working program is added to the LSI 2 as a calendar together with a calendar date as a cipher for use in a memory card mode, and a process program which collates both memory contents supplied to the EEPROM 1 with each other. The discharge capacity of the battery 3 is set at 30mAh and can supply power to the LSI 2 for 3,000hr or longer. While a wiring 4 applies a wire bonding method and a reading operation uses a contact system with an electrode 5. In such a constitution, the cipher contents of the memory device change as indicated by a user program even in a period when the memory device is kept off from a terminal equipment. Thus the secret properties can be improved with the memory device.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to memory devices such as memory cards and memory packages, and particularly to memory devices with high confidentiality.

[Conventional technology]

BACKGROUND ART As a type of memory device such as a memory card or a memory package, there is a type that uses non-volatile memory such as EPROM or EEPROM. This EPRON,
Memory devices using EEPROM do not require a power supply, so there is extremely little risk of memory contents being erased, and they have the advantage of being highly reliable (Mabe 2 Morukei Electronics, (1985) 12- No. 16, P2
56-257, 9: Nikkei Electronics (1985
) l O-21, P130) Therefore, this type of memory device is said to be suitable for applications that require high secrecy, such as in banking and medical fields (Security: Nikkei Electronics (1985) 10- No. 21, P136
), L, on the other hand, EPROM, EEP
The encryption of the memory device using RON is when creating the memory device.
Alternatively, the information is managed only when contacted by a terminal device having a writing function.

[Problem that the invention seeks to solve]

As mentioned above, in conventional memory devices using EEPROM and EPROM, the encryption is fixed.

Questions remained regarding its confidentiality.

An object of the present invention is to provide a memory device with significantly improved security.

[Means for solving problems]

The above purpose is to provide a semiconductor logic circuit that inputs a cryptographic management program, a battery that serves as its power source, and

This is achieved by integrating or compounding EEFROM and EFROM.

[Effect]

Here, there is a RAM card that has a self-management function for passwords. This has the following problems. That is, since the memory that stores information is a RAM, the built-in battery is consumed by the RAM. Therefore, increasing the storage capacity.

This is disadvantageous for long-term memory retention. Furthermore, this RAM
In a card, if the battery runs out, all stored information will be lost.In contrast, in the case of the present invention, the built-in battery only supplies power to the logic LSI for password management. Therefore, the battery can be used for a long time. Furthermore, it is possible to use a logic LSI with large power consumption. Furthermore, in the case of a modified invention, even when the battery is exhausted, the stored information is retained.As mentioned above, compared to a RAM card with a password self-management function, the present invention has an advantage in information retention. Reliability is extremely high.

〔Example〕

An embodiment of the present invention will be described below.

A 16-bit EEFROM 1 as shown in FIG.
A memory card was prepared in which two logic circuit LSIs 2, and one all-solid-state thin film lithium secondary battery 3 serving as a power source were mounted. The logic circuit LSI 2 is input with an operating program as a calendar and a process program for comparing both the calendar date and the memory contents input to the EEPROM 1 as a code when using a memory card. The discharge capacity of the thin film battery 3 is 30 mA h
This makes it possible to supply power to the LSI for over 3,000 hours. The wiring 4 was wire bonded, and reading was performed using a contact method using the electrode 5. In addition, terminal 6 for thin film battery charging
has been established. Memory card size is 86 m x 54
m Xl, 8m.

When testing the encrypted content of this memory card for three months, it was confirmed that the encrypted content changed over time.

As described above, according to this embodiment, it is possible to realize a memory card whose encryption is self-managed in the form of a calendar programmed by the user even during periods when the card is not connected to a terminal device.

Note that the logic circuit LSI used in the above embodiment was made using CMO5 circuit technology, which is suitable for the memory device of the present invention in that it can reduce the power consumption of the logic circuit LSI. .

Further, in the above embodiment, the EEFROM and the logic circuit LSI are individually mounted, but it is more desirable to use one LSI in which these components coexist, since reliability is increased.

As the battery used in the present invention, a secondary battery is advantageous in that it can be re-discharged by charging, and in particular, a lithium secondary battery has a high voltage, and even more so.

The thickness of the battery is 1! The all-solid-state thin-film lithium secondary battery used in the above embodiment is preferable because it can be made smaller than 111, and the all-solid-state thin-film lithium secondary battery is also optimal for implementing the present invention in that it can be fabricated on an LSI.

Furthermore, if a solar cell is added to the memory card of the embodiment,
Memory cards can be made more functional by eliminating the need for charging or extending the battery discharge period. Furthermore, if the logic circuit LSI is provided with a memory function, or if a high-speed memory such as CMO8-3 RAM is added to the device, higher functionality such as an increase in memory capacity and high-speed rewriting can be achieved.

〔Effect of the invention〕

According to the present invention, even during a period when the memory device is removed from the terminal device, the encrypted content of the memory device changes in 11 ways according to the user's program. For this reason.

The secrecy of the encryption is significantly improved, and as a result, the secrecy of the memory device is also significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the basic structure of a memory card according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1...EEPROM, 2...Logic circuit LSI for cryptographic management, 3...solid thin film lithium secondary battery for LSI power supply, 4...wiring, 5...memory reading electrode,
6...Battery charging electrode. 1 map of mustard

Claims (1)

[Claims] 1. The memory for storing information is EEPROM or EPRO.
A memory device characterized in that it is a ROM and has a function of self-managing a password using a semiconductor logic element backed up by a built-in battery. 2. Battery The memory device according to item 1, which is a gallithium secondary battery, particularly an all-solid-state thin film lithium secondary battery. 3. The memory device according to items 1 and 2, wherein the memory device has a thickness of 1 mm or less.