JPS63247890A - Ic card - Google Patents

Abstract

PURPOSE:To prevent break of elements, destruction of information, or the like by detecting the temperature of circuit elements constituting an information processing circuit and controlling the operation of this circuit in accordance with the detected temperature. CONSTITUTION:A ROM 2 where a control program is stored and a RAM 3 used as a data storage area are connected to a CPU 1 through a bus line 4. The CPU 1, the ROM 2, and the RAM 3 consist of a one-chip IC, and a temperature detecting circuit 6 which detects the temperature of this IC chip is provided. The operation of the CPU 1 is controlled in accordance with the state detected by the temperature detecting circuit 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an IC card, and particularly to an IC card that incorporates a CPU, a memory element, etc., and operates by receiving power supply from an external device.

[Prior Art] Magnetic cards have been widely used as card-like media that can store information. However, magnetic cards have problems in that their information storage capacity is very small and that the stored information is easily destroyed or altered by magnetic noise.

Therefore, as a card medium to solve the above problem, CPU
, so-called I, which has a built-in memory element for data storage and stores and reproduces information by communicating with external devices.
C cards are attracting attention. Various specifications have been considered for IC cards, but all IC cards have a common configuration: a CPU that controls information input/output, a ROM that stores CPU control programs, constants, etc., and a RAM that stores data. Each of these parts may be constituted by a separate or integrated integrated circuit.

In addition to using a RAM and a backup power source as a method of retaining stored data in an IC card, a method of retaining data without a backup power source using an EFROM is also considered.

[Problems to be Solved by the Invention] In the above-mentioned IC card, if a short circuit or a gate failure occurs in the connector contact for connection with an external device, and an excessive current flows through the IC chip constituting the internal circuit,
The temperature of the element rose, and there was a risk that the stored data and the element itself would be destroyed by this heat.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides an IC card with a built-in information processing circuit that performs information input/output and information storage with an external device. A configuration is adopted that includes means for detecting the temperature state of the circuit elements constituting the circuit, and means for controlling the operation of the information processing circuit according to the detected state of the detecting means.

[Function] According to the above configuration, the temperature state of the information processing circuit inside the IC card can be detected, and based on this, appropriate control can be performed to prevent element destruction, information destruction, etc.

[Example] Hereinafter, the present invention will be described in detail based on the example shown in the drawings.

Figure 1 is a block diagram showing the structure of the internal circuit of an IC card employing the present invention. In Figure 1, the symbol l indicates information input/output control and storage between external devices. A CPU composed of a microprocessor, etc., that performs control operations such as data management.The CPU is connected to a ROM 2 that stores a control program (described later) via a path line 4 consisting of a data bus and an address bus, and is used as a data storage area. RAM3 is connected.

The CPUI has a built-in interface circuit for inputting and outputting information with an external device, and this interface circuit is connected to an electrode 8 of a connector coupled to the external device. The interface circuit uses the card's CPU reset signal (R5T) and clock (CLK).
), input/output signal (Ilo) signal, etc.

Further, the power supply voltage necessary for the operation of the IC card is also supplied via one of the electrodes 8 of the connector.

In this embodiment, the CPUI, ROM2, and RAM3 are composed of one IC chip, and a temperature detection circuit 6 is provided to detect the temperature of this IC chip.

The configuration of the temperature detection circuit 6 is shown in FIG. 2. In FIG.
It is fixed to the IC chip forming part 3 or a circuit board near it, and causes a change in resistance value depending on the detected temperature. Thermistor 11 is connected in series with voltage dividing resistor 10 and connected between power supply voltage Vcc and ground. Thereby, the terminal voltage of the thermistor 11 changes according to the detected temperature. The terminal voltage of the thermistor 11 is input to one input terminal of the comparator 12.

On the other hand, a reference voltage 13 formed using a Zener diode or the like is connected to a manual input terminal of the comparator 12. The reference voltage 13 is set to the voltage generated by the thermistor 11 at the maximum allowable temperature of the IC chip.

The output signal produced at the output terminal 20 of the comparator 12 is
The interrupt signal is input to the CPUI via the signal line 5 in FIG. 1 as an interrupt signal to notify of a temperature abnormality.

FIG. 3 shows the control procedure of the CPU in the configuration of FIG. 1.

Input/output information to/from external devices is done in step 3 in Figure 3.
1. It is processed by the loop of S2.

In step S1, each part of the device operates based on power supplied from the external device, and information is input/output to/from the external device.

In step S2, it is determined whether the comparator 12 of the temperature detection circuit 6 is outputting a high level via the signal line 5.
In other words, the IC that constitutes the CPUI, ROM2゜RAM3
It is determined whether an abnormality (abnormal temperature rise in this case) has occurred in the temperature of the chip.

If a temperature abnormality occurs, the CPU
Since the interrupt signal is input to I, the process moves to step S3, and the CPU outputs a signal indicating a temperature abnormality to the external device from the communication terminal of the terminals of the electrode 8 of the connector. Based on this temperature abnormality notification, the external device side performs appropriate processing such as stopping power supply to the IC card and issuing an alarm.

In step S4, the signal input gate of the interface circuit connected to the electrode 8 is cut off.

Here, CPU reset signal R5T, clock CL
Gates of K, power supply voltage Vcc, input/output control signal I10, etc. are cut off.

In step S5, the IC card is ejected from the external device by automatic processing of the external device based on the temperature abnormality notification in step S3 or manual processing by the operator based on a warning.

As described above, when a temperature abnormality occurs in the IC chip of an IC card, the card's CPUI detects this and takes measures such as stopping signal input/output and ejecting the card.
Destruction of C card circuit elements, erasure or modification of stored data,
Destruction can be prevented. In the above, only the presence or absence of temperature abnormality is detected using a comparator, but as shown in Figure 4, the terminal voltage of the thermistor 11 is formed by connecting resistors R1 to Rn in series Comparators 12 each compared with a weighted reference voltage.
The digital temperature data may be compared using 0, quantized to about 4 bits to 8 bits, and then input to the CPUI.

In such a configuration, it goes without saying that the determination process in step S3 in FIG. 4 is not a detection of the presence or absence of an interrupt, but a software process such as comparing detected temperature data with an upper limit temperature value.

11ri1'' Above, we have shown an example in which the temperature detection signal is input to the CPU1 of the IC card, and the CPUI performs error processing based on this, but with the configuration shown in Figure 5, the temperature detection signal is input to the external device. The error processing may be performed on the external device side.

For example, when the external device H and the IC card are connected through the electrodes 8 and 8' of the connector as shown in FIG. 5, the output of the temperature detection circuit 6 is input to the external device H side via the electrode 8'. In this case, it is assumed that the temperature detection circuit 6 has the configuration shown in FIG.

On the external device H side, the IC is activated by the interrupt signal of electrode 8'.
To detect temperature abnormalities in a card and cause the IC card to perform appropriate error handling.

FIG. 6 shows the control procedure in the configuration of FIG. 5.

What is different in FIG. 6 from the procedure in FIG. 3 is that the temperature abnormality detection in step S2' is performed on the external device H side, and that step S3, which precedes step S3, is based on the temperature abnormality detection in step S2''. External device H at '
The processing of the other steps is exactly the same as described above, except that an interrupt signal is inputted to the CPUI via one of the electrodes 8 of the connector.

Even with such processing, if a temperature abnormality occurs, take appropriate measures such as stopping signal input/output or ejecting the card.
Destruction of circuit elements of the IC card and destruction of stored information can be prevented.

According to the configuration shown in FIG. 5, the hardware and software configuration on the IC card side can be simplified and the manufacturing cost of the card can be reduced.

In addition, CPU1, ROM2, and RAM3 are separate ICs.
In the case of a chip, etc., as shown in FIG.
3 may be provided and the temperature detection signal may be inputted to the external device H via the electrodes 81 to 83 of the connector.

According to such a structure, since the temperature of each chip can be detected on the external device H side, more complex measures such as changing error handling depending on which IC chip is causing a temperature abnormality are possible. .

In this case as well, temperature detection is performed on the external device side, so the IC
There is no burden on the hardware or software configuration on the card side.

Note that in the configurations shown in FIGS. 5 and 7, a temperature detection circuit that outputs temperature information as quantized digital data as shown in FIG. 4 may also be used.

[Effects of the Invention] As is clear from the above description, according to the present invention, in an IC card having a built-in information processing circuit that performs information input/output and information storage with an external device, the information processing circuit is means for detecting the temperature state of the constituent circuit elements;
Since the structure includes means for controlling the operation of the information processing circuit according to the detection state of the detection means, it is possible to prevent the information processing circuit of the IC card and the stored data from being destroyed, and to prevent the stored data from being destroyed. This has the excellent effect of improving retention reliability.

[Brief explanation of drawings]

Fig. 1 is a blow diagram showing the structure of an IC card adopting the present invention, Fig. 2 is a circuit diagram of the temperature detection circuit of the 1st VIJ, and Fig. 3 shows the processing procedure of the CPU shown in Fig. 1. Flowchart diagram, FIG. 4 is a circuit diagram showing different configurations of the temperature detection circuit, FIG. 5 is a block diagram showing different structures of the IC card, and FIG. 6 is a flowchart showing the processing procedure of the CPU in FIG. 7 are block diagrams showing a modification of the configuration shown in FIG. 5. l...CPU 2...ROM3...R
AM 5...electrode, 6.61-63...
Temperature detection circuit 10...Resistor 11...Thermistor 12.
... Comparator Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] 1) In an IC card incorporating an information processing circuit that inputs/outputs information to/from an external device and stores information, means for detecting the temperature state of a circuit element constituting the information processing circuit; An IC card characterized by comprising means for controlling the operation of an information processing circuit according to the detection state of the detection means. 2) The IC card according to claim 1, further comprising means for cutting off power supply to the information processing circuit when the detection circuit detects a temperature abnormality. 3) If a temperature abnormality is detected by the detection circuit,
I according to claim 1 or 2, further comprising means for notifying the external device of this fact.
C card.