JP3327324B2 - Non-contact IC card failure determination method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact type IC card, which is used to determine whether or not a non-contact type IC card has failed and its status when the non-contact type IC card fails. The present invention relates to a method and an apparatus.

[0002]

2. Description of the Related Art A non-contact type IC card, like a contact type IC card, may be exposed to various situations because it is carried and used by human beings, and is subjected to more severe conditions than ordinary LSIs and the like. In fact, there is a high risk of failure. In addition, depending on the purpose of use, if it becomes unusable due to a failure or the like, it may cause significant inconvenience.
Because it is necessary to determine whether the cause is on the C card side or the card reader side, the card issuer or the publisher issues a prompt response in the event of a complaint from the user as a failure. is necessary. If an IC card is inserted into an IC card reader / writer and the data cannot be exchanged normally for some reason and cannot be used because the IC card is used, a complaint will be sent to the card issuer or sales agency. The cause of the unusability could not be clarified on site. this is,
Conventionally, this is because a card issuer or a card manufacturer expert judges the failure by exposing the surface of the IC chip and observing it with a microscope or the like.

[0003]

As described above, in the conventional failure judgment, it is time-consuming to carry it to a card issuer or a card manufacturer, so that it takes time. Publisher is non-contact type I
There was a drawback that the cause of the failure of the C card could not be ascertained, and the response to the card holder was delayed.

An object of the present invention is to provide a method and an apparatus capable of automatically determining a failure of a non-contact type IC card which has been claimed as a failure in a short time in view of the above-mentioned drawbacks.

[0005]

According to the present invention, there is provided a method for determining a failure of a non-contact type IC card, wherein a signal receiving means of the non-contact type IC card to be tested is supplied with an AC voltage matching a tuning frequency inside the card. A signal is transmitted, and an impedance is calculated by measuring a voltage and a current value at the time of transmitting the AC voltage signal, and the calculated impedance value is compared with a value in a normal case. This is to determine.

The noncontact IC card failure judging device according to the present invention transmits a signal for transmitting an AC voltage signal matching a tuning frequency inside the card to a signal receiving means of the noncontact IC card to be tested. Means, and impedance calculating means for calculating impedance by measuring the voltage and current values at the time of transmitting the AC voltage signal, respectively, and comparing the calculated impedance value with a value in a normal case. Comparing means for judging a failure.

[0007]

According to the present invention, an AC voltage signal matching a tuning frequency is transmitted to a signal receiving means of a faulty non-contact type IC card, and the current value at that time is measured to obtain an impedance. The failure mode can be estimated by calculating the value and judging and classifying the result by a numerical value, so that the failure can be determined without requiring special knowledge.
Further, according to the present invention, it is possible to provide a simple single-frequency AC power supply, a measuring instrument for AC voltage and current, and a simple and inexpensive apparatus which can obtain a determination result by simple calculation.

Hereinafter, embodiments of the present invention will be described in more detail.

Usually, a signal receiving circuit of a non-contact type IC card has a tuning circuit because only a signal of a specific frequency transmitted from the signal transmitting circuit is used in an internal circuit. During normal operation, the signal component extracted by the tuning circuit reaches the internal circuit and performs a predetermined operation.

Therefore, if the frequency characteristics of the impedance of the tuning circuit and the internal circuit portion at normal time are grasped in advance, it is possible to determine whether or not a failure has occurred by comparing the frequency characteristics of the test object with the measurement results.

However, in order to perform this measurement, a mechanism for measuring the current and the voltage over a wide frequency band is required. Are expensive and not practical.

Therefore, the present invention proposes a method for determining and analyzing a failure in a short time and with an inexpensive device based on the following principle.

FIGS. 1A and 1B show a non-contact type IC card 10 used in the present invention and an opposing signal transmission circuit 20.
3 is an equivalent circuit diagram of FIG. In FIG. 3, the input impedance Zin of the non-contact type IC card 10 as viewed from the outside represents the impedances of the coil, the capacitor, and the internal circuit portion as ZL (f) and ZC, respectively.
(F) and Z0 (f), the following is obtained.

[0014]

(Equation 1) The value of Zin (f) is the value of the applied AC voltage V
It can be calculated by dividing (f) by the AC current value I (f) at that time.

Here, assuming that the tuning frequency of the non-contact type IC card 10 at normal time is f0,

[0016]

(Equation 2) From

[0017]

(Equation 3) Becomes Therefore, the input impedance Zin (f0) of the non-contact type IC card with respect to the AC voltage having the tuning frequency f0
Becomes equal to the value of only the internal circuit (that is, Z0 (f0)).

Further, the impedance of the internal circuit of a normal non-contact type IC card has a substantially fixed value for the same type of chip, though there is a variation due to the variation of the chip.

Next, a case where an electrical failure occurs in the circuit of the non-contact type IC card will be described.

FIGS. 2A and 2B show a case where a failure such as a short circuit or a leak path at a circuit junction or a wiring portion occurs in an internal circuit portion of the non-contact type IC card. In such a failure, since a large current flows, the input impedance is lower than that in a normal state.

The impedance Zs (f) of the internal circuit portion when a short circuit occurs is because the parallel impedance Z1 (f) of the leak (or short-circuit portion) portion is sufficiently smaller than Z0 (f).

[0022]

(Equation 4) The input impedance of the non-contact IC card 10 is

[0023]

(Equation 5) And if the resonance frequency is f0,

[0024]

(Equation 6) From

[0025]

(Equation 7) Becomes

FIGS. 3A and 3B show a case where a failure such as a disconnection or an increase in series resistance at a junction occurs in the internal circuit of the non-contact type IC card 10 and the current becomes difficult to flow. , The input impedance is higher than in the normal state.

The impedance Z of the internal circuit when a disconnection occurs
d (f) is because the series impedance Z2 (f) of the disconnection (or DC resistance insertion) portion is sufficiently larger than Z0 (f).

[0028]

(Equation 8) The input impedance of the non-contact IC card 10 is

[0029]

(Equation 9) And if the resonance frequency is f0,

[0030]

(Equation 10) From

[0031]

[Equation 11] Becomes

Next, a failure in the tuning circuit will be described.

FIGS. 4A and 4B show a case where a failure such as disconnection or insertion of a series resistor has occurred at a stage subsequent to the coil of the tuning circuit of the non-contact type IC card 10, and the input impedance is only the coil of the tuning circuit. Is determined.

Therefore, the input impedance of the non-contact type IC card at this time is

[0035]

(Equation 12) Here, assuming that the resonance frequency is f0, the non-contact type I
The impedance value ZL (f0) of the tuning circuit of the tuning circuit of the C card 10 with respect to the tuning frequency is such that the inductance L cannot be increased structurally.

[0036]

(Equation 13) As described above, it can be seen that, regardless of which failure occurs, if an electrical failure occurs in the circuit of the non-contact type IC card, a change occurs in the input impedance of the internal circuit.

From this, the input impedance of the test target card with respect to the tuning frequency is measured and compared with the value of the normally operable card which is grasped in advance, thereby making it possible to prevent the non-contact type IC card from malfunctioning. The presence or absence of occurrence can be detected.

The equivalent circuit is not limited to the example shown in FIG.
It can be changed according to the configuration of 0.

[0039]

FIG. 5 is a block diagram showing the configuration of an embodiment of a failure determination device for a non-contact IC card according to the present invention. The contact type IC card 10 includes a signal receiving unit 11 and an internal circuit 12. The configuration and function of each unit in the non-contact type IC card failure determination device 20 will be described. The single-frequency AC power supply 21 is a non-contact IC card 10 to be tested.
Is generated, and a voltage is applied to the non-contact type IC card 10 via the signal transmission unit (signal transmission means) 22. The single-frequency AC voltmeter 23 and the single-frequency AC ammeter 24 measure the AC voltage and the AC current value of the frequency f0 applied to the signal transmission unit 22, respectively.

The impedance calculator (impedance calculator) 25 divides the voltage measurement value notified from the single-frequency AC voltmeter 23 by the current value notified from the single-frequency AC ammeter 24 to determine Non-contact IC card 1
An input impedance value of 0 is calculated.

The normal value storage section 26 stores the impedance value of a normal non-contact type IC card 10 of the same type as the test object as a normal value.

Comparison (failure determination) section (comparison determination means) 27
In accordance with a rule set in advance based on the normal value notified from the normal value storage unit 26, the presence / absence of failure of the non-contact IC card 10 to be tested is determined from the calculated impedance value notified from the impedance calculation unit 25. Is determined. The operation / display / controller unit 28 performs control operations for starting and stopping the test of the present apparatus, displaying results, and the like.

FIG. 6 shows an example of the calculation result of the input impedance of the non-contact type IC card 10 and the corresponding rules for the failure state. In FIG. 6, the calculated value Z of the input impedance
in (f0) is normalized by a normal value Z0 (f0).
Here, the determination reference value for distinguishing between the normal non-contact IC card 10 and the other non-contact IC card 10 having a failure is a value shifted from the impedance value of the normal non-contact IC card 10 by 0.5 digit.

In this embodiment, the determination reference value is set to 0.1.
Although five digits are used, the circuit content may be different depending on the IC card to be determined, so a value that is most easily classified may be provided. Further, the tuning frequency differs for each type of the non-contact IC card 10, but is the same for the same ticket type. Since the failure determination device 20 cannot determine the tuning frequency, the failure determination device 2 checks the tuning frequency and the normal value of the IC card to be tested in advance, and matches the failure frequency.
0 needs to be prepared.

[0045]

The method and apparatus for determining a failure of a non-contact IC card according to the present invention can be used when the non-contact IC card breaks down.
An AC voltage signal matching the tuning frequency is transmitted to the signal receiving means of the IC card, and the current / current
The AC voltage generator, AC voltmeter, and AC ammeter are designed to determine the presence or absence of a failure and its state by calculating the impedance by measuring the voltage and comparing the impedance with a predetermined normal value. In addition to the fact that only a single frequency f0 can be handled, a fault can be detected by determining only whether or not the calculated value of a single impedance is within a specified range. Compared with the method of observing the chip surface of an impedance analyzer or an IC card, a very inexpensive and compact failure determination device can be realized. Further, by using the present method and apparatus, it is possible to easily and quickly check a card without special knowledge of an operator.

[Brief description of the drawings]

FIG. 1 is an equivalent circuit diagram and a frequency characteristic diagram of a non-contact type IC card used in the present invention and a signal transmission circuit opposed thereto.

FIG. 2 is an equivalent circuit diagram and a frequency characteristic diagram of a signal transmission circuit when a failure such as a short circuit occurs in an internal circuit portion of a non-contact type IC card used in the present invention.

FIG. 3 is an equivalent circuit diagram and a frequency characteristic diagram of a signal transmission circuit when a failure such as a disconnection occurs in an internal circuit portion of the non-contact type IC card used in the present invention.

FIG. 4 is an equivalent circuit diagram and a frequency characteristic diagram of a signal transmission circuit when a failure such as a disconnection occurs at a stage subsequent to a coil of a tuning circuit in an internal circuit portion of the non-contact IC card used in the present invention.

FIG. 5 is a block diagram showing a configuration example of an embodiment of a failure determination device for a non-contact type IC card according to the present invention.

FIG. 6 is a diagram showing a calculation result of an input impedance according to the present invention and a rule corresponding to a failure state.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Non-contact type IC card 11 Signal receiving part 12 Internal circuit 20 Non-contact type IC card failure determination device 21 Single frequency AC power supply 22 Signal transmission part (signal transmission means) 23 Single frequency AC voltmeter 24 Single frequency AC Ammeter 25 Impedance calculation unit (impedance calculation unit) 26 Normal value storage unit 27 Comparison (failure determination) unit (comparison determination unit) 28 Operation / display / control unit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01R 31/00 G01R 31/28-31/3193 G06K 17/00

Claims (2)

(57) [Claims] 1. An AC voltage signal matching a tuning frequency inside a card is transmitted to a signal receiving means of a non-contact type IC card to be tested, and a voltage / current value at the time of transmitting the AC voltage signal is measured. A non-contact type IC card failure determination method, comprising calculating an impedance by comparing the calculated impedance value with a normal value. 2. A signal transmitting means for transmitting an AC voltage signal matching a tuning frequency inside the card to a signal receiving means of a non-contact type IC card to be tested, and a voltage / current at the time of transmitting the AC voltage signal. Impedance measuring means for calculating the impedance by measuring the respective values; and comparing and judging means for comparing the calculated impedance value with a value in a normal case and judging a failure in an internal circuit of the IC card. Non-contact IC card failure determination device.