JPS6311395A - Ic card - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to an IC card that transmits and receives signals to and from an external device using a contact method using terminals.

(Conventional technology) Memory IC chips and CPU
So-called IC cards with embedded IC chips, etc., have two major characteristics: confidentiality and large storage capacity, and have been put into practical use as an alternative to conventional magnetic cards, and will be put into practical use in a variety of fields in the future. It is thought that this will continue to evolve.

By the way, on the other hand, the issue of the reliability of IC cards is being discussed.

Currently, there are two types of IC cards: the contact type, which has a terminal and directly sends and receives electrical signals through this terminal, and the non-contact type, which uses magnetic signals to send and receive signals indirectly. Something has been put into practical use. FIG. 4 is a perspective view showing the external appearance of a contact type IC card. In the figure, 31 is an IC card body made of an insulating material, such as an insulating resin, and 32 is this card body 31.
IC chips such as memory ICs embedded in the 3
3 is a terminal for transmitting and receiving signals between this IC chip and an external device. As a matter of course, the non-contact method has higher credibility in terms of the operating environment. However, the contact method shown in FIG. 4 is superior in terms of the structure of the IC card itself, manufacturing cost, signal transmission efficiency, etc. Therefore, it is conceivable that contact type IC cards will become mainstream in the future.

By the way, the I
C chips are used for memory ICs as well as microprocessor ICs.
These are normal ICs, but there have been no conventional IC chips that have been modified to match the contact method to improve their reliability. For this reason, when using a conventional IC card by connecting it to an external device, the IC card
If the card terminal becomes non-contact even temporarily, the I
In the case of the C card, the buried C card will malfunction, and in the worst case, it will be destroyed. In particular, the buried C is 0MO8 type IC.
This is even more true in the case of

In addition, if the buried C is 0MO8 type, when the IC card is used as part of a microprocessor system and the terminal becomes non-contact as described above, the same 70-
In this case, the microprocessor system will definitely malfunction, and in the worst case, it will be destroyed.

In addition, in IC cards that have a built-in power supply and terminals for connecting to external devices, but can be used alone without connecting to external devices, those terminals are always in a floating state. Therefore, the same phenomenon as above occurs.

In this way, in conventional contact-type IC cards, from the viewpoint of protecting the transmitted data and the IC card itself, no circuit measures have been taken to prevent the terminal from being in an instantaneous non-contact state. There is a problem of low gender.

As one of these countermeasures, it is conceivable to connect a pull-up resistor or a pull-down resistor to the signal path from the terminal of the IC card to the buried C chip. However, since these resistors are externally connected to the embedded FF1LC chip, they are disadvantageous in terms of price, and there is also the problem of increased power consumption because current constantly flows through the pull-up or pull-down resistors. Occur.

(Problems to be Solved by the Invention) As described above, conventional IC cards have problems in that an attempt to improve reliability increases manufacturing costs and increases current consumption.

This invention was made in consideration of the above-mentioned circumstances, and its purpose is to provide an IC that can improve reliability without causing an increase in manufacturing cost or current consumption.
The purpose is to provide cards.

[Structure of the Invention] (Means for Solving the Problems) The IC card of the present invention includes a base, an integrated circuit chip provided in the base, and a signal of the integrated circuit chip provided in the base. It consists of a terminal for transmitting and receiving signals between the input/output section and an external device, and a terminator circuit installed in the base and connected to each of the signal input/output sections of the integrated circuit chip. .

(Function) In the IC card of the present invention, a terminator circuit is connected to each of the signal input/output sections of the integrated circuit chip provided in the base, and the terminator circuit allows the signal input/output section to be pulled up or down or the signal input/output section to be pulled up or down. It is designed to hold the signal at .

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the IC card of the present invention. In the figure, numeral 10 is an IC card body, and its structure is as shown in FIG.
The C chip is buried. 11 is memory I
These are embedded C chips such as C1 microprocessor ICs and logic circuit ICs. 12 is a signal terminal for connection with the outside, and 13 is a power supply terminal for applying an operating voltage to the buried 11G chip 11. And the above-mentioned buried installation 6
The one-C chip 11 is connected to each of the above-mentioned terminals 12 via internal wiring 14. Roughly speaking, terminator circuits 15 are connected to the middle of the internal wiring 14 connected to the signal terminals 12, respectively. A program signal P and data D are supplied to each of the terminator circuits 15 from the buried C-chip 11, respectively.

FIG. 2 is a circuit diagram showing a specific configuration of each of the terminator circuits 15 described above. The program signal P from the buried C-chip 11 is supplied to an inverter 21, and the output signal of this inverter 21 is sent to another inverter 22.
is supplied to The other data D is sent to the clocked inverter 2 via two inverters 23 and 24 connected in series.
5. The operation of the clocked inverter 25 is controlled based on the signal A obtained as the output signal of the inverter 21 and the signal φ obtained as the output signal of the inverter 22. The output data of the clocked inverter 25 is then supplied to the input end of an inverter 26 whose output end is connected to one of the signal terminals 12. The input and output terminals of the inverter 26 are connected in antiparallel to the input and output terminals of another inverter 27.

It should be noted that each terminator circuit 15 described above is connected to the buried C chip 1.
It may be integrated into one.

In such a configuration, each of the terminator circuits 15
performs a pull-up or pull-down operation of each internal wiring 14 or a holding operation of the signal of each internal wiring 14 based on the program signal P and data D from the buried C-chip 11. That is, when the program signal P is at the H level, the signal 1 obtained as the output of the inverter 21 is at the L level, and the signal φ obtained as the output of the inverter 22 is at the H level.
At this time, clocked inverter 25 operates as a normal inverter. Then, when an H level is supplied as data D when the signal P is at an H level, the output signal of the inverter 26 whose output end is connected to the internal wiring 14 goes to an H level.
level, and this internal wiring 14 is pulled up inside the cylinder. On the other hand, if L level is supplied as data D when signal P is at H level, the output signal of the inverter 26 becomes L level, and this internal wiring 14
is pulled down into the cylinder.

When the program signal P is at L level, the inverter 21
The belief obtained as the output of Q? is H level, inverter 2
The signal φ obtained as the output of the clocked inverter 25 becomes L level, the clocked inverter 25 does not operate, and its output terminal becomes a high impedance state. That is, the input end of the inverter 26 is cut off from the output end of the clocked inverter 25, and only the inverter 27, whose input end is connected to the internal wiring 14, supplies a signal to the inverter 26. Therefore, when the program signal P is set to L level, the previous signal on the internal wiring 14 is transferred to the inverter 2.
Positive feedback is given by 7.26. As a result, the internal wiring 14
The signal P is held even after the signal P is set to the L level and continues to be pulled. FIG. 3 is a diagram summarizing the above functions of each of the terminator circuits 15.

As described above, in the IC card of the above embodiment, each terminator circuit 15 can perform a pull-up or pull-down operation on the internal wiring 14 or a signal holding operation of the internal wiring 14. Therefore, by keeping each terminator circuit 15 in a pull-up or pull-down state,
Even if the signal terminal 12 becomes non-contact while using this IC card connected to an external device, it may malfunction, but damage to the IC card can be prevented and reliability can be improved. It is possible to improve the

In addition, by setting each terminator circuit 15 in a signal holding state, when the speed of the signal exchanged between this IC card and an external device is relatively slow, such as an initial reset signal, the terminal 12 is in a non-contact state. Even if the current occurs, the immediately preceding signal is retained, making it possible to continue operation thereafter, resulting in a significant improvement in reliability.

Furthermore, when using the built-in power supply and operating the IC card alone without connecting it to an external device, the terminal 12 will naturally be in an open state, but each terminator circuit 15 can be pulled up or By keeping it in the pull-down state, it is possible to prevent not only malfunction but also destruction of the IC card itself.

In addition, when each terminator circuit 15 performs pull-up or pull-down of the internal wiring 14 or holds a signal, the output signal of the inverter 26 is set to H level or L level to perform the pull-up or pull-down function or hold the signal. However, since the current consumption in the inverter 26 is only a transient voltage component when the level of the internal wiring 14 is reversed, pull-up and pull-down are performed using a resistor as in the conventional method. The current consumption is significantly reduced compared to the case where the

Furthermore, each terminator circuit 15 is buried in the C chip 11.
Terminator circuit 1
5 can prevent an increase in the manufacturing price of the IC card itself.

[Effects of the Invention] As described above, according to the present invention, it is possible to provide an IC card that can improve reliability without causing an increase in manufacturing cost or current consumption.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of an IC card according to the present invention, FIG. 2 is a circuit diagram showing a specific configuration of a part of the circuit of the above embodiment, and FIG. FIG. 4 is a diagram illustrating the functions of the circuit, and is a perspective view illustrating the external appearance of a contact type IC card. 10... IC card body, 11... Buried C chip, 12... Signal terminal, 13... Power supply terminal, 14
. . . Internal wiring, 15. Terminator circuit, 21.
22.23.24.26.27...Inverter, 25
...Clocked inverter.

Claims (1)

[Claims] 1. A base, an integrated circuit chip provided in the base, and a signal input/output section of the integrated circuit chip provided in the base for transmitting and receiving signals between the external device. An IC card comprising: a terminal; and a terminator circuit provided within the base and connected to each signal input/output section of the integrated circuit chip. 2. The IC card according to claim 1, wherein the terminator circuit is formed within the integrated circuit chip.