JPS62282389A - Reader/writer for portable recording medium - Google Patents

Abstract

PURPOSE:To prevent the generation of the abnormality such as the malfunction of a portable recording medium or the failure of information by providing a means for outputting a reset signal to the medium when an operating voltage supplied to the portable recording medium is below a prescribed value. CONSTITUTION:When an IC card is loaded and the contact of the IC card is connected to the contact of a card reader/writer, a control signal S1 is outputted from a control part 1, a transistor 5 is turned on, a transistor 7 is turned on, and a direct current voltage from a direct current power source part 3 is supplied to the IC card as the operating voltage Vcc. A reset signal output circuit 21, when the operating voltage Vcc is above a reference voltage, outputs a set signal to a reset signal line 15 and the operating voltage Vcc is supplied to a microcomputer and a memory in the IC card. When according to the abnormality in the circuit of the operating power source output terminating side of the control part 1, the operating voltage Vcc is lowered and below the reference voltage, the reset signal output circuit 21 outputs the reset signal to the signal line 15.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Purpose of the Invention (Industrial Application Field) The present invention relates to a reading/writing device for a portable recording medium typified by an IC card. .

(Prior Art) As is well known, an IC card is a credit card-sized plastic card with a memory and a microcomputer embedded therein. This IC card has a large memory capacity and is equipped with a calculation control unit such as a microcomputer, so it is suitable for storing various information that requires a large storage capacity and information that requires calculation. There is. Moreover, since it is of a size suitable for carrying, it has been put into practical use as a shopping card, health check card, etc.

This IC card is loaded into a card reading/writing device and exchanges information between the two. FIG. 3 shows the configuration of a power supply section of a conventional card reading/writing device.

In the figure, 1 is a control section mainly composed of a microcomputer, and 3 is a DC power supply section.

When the control signal S+ is output from the control unit 1 with the IC card loaded in the card reading/writing device, the transistor 5 is turned on, and accordingly, the 1-range staff is turned on. As a result, the DC voltage from the DC power supply unit 3 is outputted from the contact unit (not shown) to the IC card via the control unit 1 as the operating voltage Vcc. At the same time, a set signal $2 is output from the control unit 1 and supplied to the IC card via the contact unit, and accordingly, the microcomputer and memory of the IC card are set.
Said work! 7I voltage Vcc is supplied.

However, in the above-mentioned conventional card reading/writing device, if an abnormality occurs in the transistor 5 or transistor 7 in the subsequent stage of the IT, II 111 section 1, or in other parts, such as an accidental component or disconnection, the problem may occur due to this. Even if the operating voltage Vcc decreases, the control section 1 cannot detect this, so the control section 1 does not supply a reset signal to the IC card. Therefore, as the operating voltage Vcc decreases, the microcomputer in the IC card malfunctions and runs out of control, or the data in the memory is destroyed.

(Problems to be Solved by the Invention) As mentioned above, in the conventional portable recording medium reading/writing device, when the operating voltage supplied to the portable recording medium decreases, the portable recording medium There were problems such as malfunctions and information destruction.

The present invention has been made in view of the above-mentioned problems, and its purpose is to prevent abnormalities such as malfunctions and information destruction of portable recording media even when the above-mentioned operating voltage decreases. An object of the present invention is to provide a portable recording medium reading/writing device.

[Structure 1 of the Invention (Means for Solving the Problems) In order to solve the above problems, the present invention provides a portable recording medium that is connected to a portable recording medium to supply operating power to the portable recording medium. In a portable recording medium reading/reading device that exchanges information with a recording medium, monitoring an operating voltage supplied to the portable recording medium;
When this operating voltage falls below a predetermined value, a reset signal is output to the portable recording medium (action). When the portable recording medium is loaded in the reading/writing device, it is supplied to the portable recording medium. The operating voltage applied is detected. Detected work! When the II voltage falls below a predetermined value, a reset signal is forcibly output from the reset signal output means to the portable recording medium. This prevents abnormalities such as malfunctions and information destruction of the portable recording medium due to a drop in operating voltage.

(Embodiment) Hereinafter, a preferred embodiment of the portable recording medium reading/writing device according to the present invention will be described based on the drawings.

FIG. 1 shows the configuration of an embodiment of a portable recording medium reading/writing device according to the present invention, and the figure particularly shows a voltage supply section of this reading/writing device.

A power supply line 9 is connected to a control unit 1 mainly composed of a microcomputer, and a transistor 7 is interposed in this power supply line 9. Then, the DC voltage from the DC power supply section 3 is smoothed by the capacitor C and the resistor R interposed between the ground line 11 via the transistor 7, and then is converted to the operating voltage Vcc at the contact section (
(not shown).

Further, a control signal line 10 is connected to the control section 1, a control signal S+ is outputted to the control signal line 10, and a logic circuit 12. It is output as a base control signal of the transistor 5 via the resistor R2 and the diode 13. This transistor 5 controls the switching of the transistor 7, and when the transistor 5 is turned on, the transistor 7 is turned on so that the DC voltage from the control section 1 is outputted to the contact section.

Further, a reset signal line 15 is connected to the control section 1, and a reset signal from the control section 1 is outputted to the contact section via the logic circuit 17.

On the output end side of the power supply line 9, a hit signal output circuit 21 is connected between the power supply line and the reset signal line 15.
is connected. As shown in FIG. 2, this reset signal output circuit 21 is mainly composed of a comparator 21a, a Zener diode 21b, and a transistor 21c, and outputs an H-level set signal when the operating voltage Vcc exceeds a reference voltage. is output to the reset signal line 15.

On the other hand, the output end of the limiting circuit 23 is connected between the resistor R2 and the diode 13 of the control signal line 10.

This restriction circuit 23 is, for example, A of a card reading/writing device.
If the C power supply or DC power supply unit 3 malfunctions due to voltage fluctuations or momentary interruptions due to strong noise, or if the signal level on the control unit 1 side drops, the transistor 5 is forcibly turned off and the IC card is disconnected. This is to stop the supply of operating voltage VCC to. The internal configuration of this limiting circuit 23 can be the same as that of the reset signal output circuit 21.

This embodiment has the above configuration, and its operation will be explained below.

When AC power is turned on to the card reading/writing device, an IC card is loaded, and the contacts of the IC card and the card reading/writing device are connected, first, the control unit 1 outputs a control signal S1. be done. Along with this output, transistor 5
turns on. This turning on of transistor 5 turns on transistor 7, and the DC voltage from DC power supply section 3 is supplied to the IC card as operating voltage Vcc through a smoothing circuit consisting of capacitor C and resistor R.

At this time, the reset signal output circuit 21 monitors the rise of the operating voltage CC, and when the operating voltage Vcc becomes equal to or higher than the base tp- voltage determined by the Zener diode 21b, the comparator 21a outputs an H level signal. The output transistor 21C is turned on. As a result, a set signal is output to the reset/signal line 15, and by supplying this set signal to the IC card, the I/O
The operating voltage Vcc is supplied to the microcomputer and memory in the C card.

On the other hand, when an abnormality occurs in the circuit on the operating power output end side of the control unit 1 and the operating voltage CC decreases to below the reference voltage, the output of the reset signal output circuit 21 becomes L level and reset to the reset signal line 15. A signal is output. At this time, the control unit 1 does not detect a voltage drop in the operating voltage Vcc due to a circuit abnormality on the operating voltage output side, and therefore, even if the operating voltage VCC drops below the reference voltage, the control unit 1 does not send a reset signal. is not output. However, the set signal supplied from the control section 1 and the reset signal from the reset signal generation circuit 21 are ANDed, and the reset signal is supplied to the IC card. Therefore, the IC card is always supplied with the operating voltage VCC of a predetermined level or higher, thereby reliably preventing the microcomputer from running out of control or destroying data in the memory due to a drop in the operating voltage Vcc.

Next, a case where there is an abnormality not on the output terminal side of the operating voltage Vcc but on the AC power source or DC power supply section 3 side of the card reading/writing device will be described.

During normal operation, the limiting circuit 23 outputs an H level signal, so the transistor 5 is controlled by the control signal S1 from the control section 1. However, if an abnormality occurs in the power supply due to a momentary interruption or noise on the AC power source side, the microcomputer in the control section 1 goes out of control and becomes unable to output accurate signals. At this time, the limiting circuit 23 monitors the decrease in the signal level on the control section 1 side, and when the signal level falls below a predetermined level, outputs an L level signal to forcibly turn off the transistor 5. As a result, transistor 7
is also turned off, and the supply of operating voltage Vcc to the IC card is stopped. Therefore, as described above, abnormalities such as runaway of the microcomputer in the IC card and destruction of data in the memory due to a drop in the operating voltage CC are prevented.

[Effects of the Invention] As explained in detail above, according to the present invention, the operating voltage supplied to the portable recording medium is monitored, and when the operating voltage becomes below a predetermined value, the portable recording medium is reset. The configuration includes reset signal output means for outputting a signal. Therefore, abnormalities such as runaway of the microcomputer in the portable recording medium and destruction of data in the memory due to a drop in the voltage supplied to the portable recording medium are reliably prevented, and reading/writing of the portable recording medium is prevented. The reliability of the writing device is improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of a portable recording medium reading/writing device according to the present invention, FIG. 2 is a block diagram showing the configuration of a reset signal generation circuit, and FIG. FIG. 2 is a block diagram showing the configuration of a portable recording medium reading/writing device. 1... Control section 3... DC power supply section 21... Reset signal generation circuit 23... Limiting circuit

Claims (1)

[Claims] (1) In a portable recording medium reading/writing device that is connected to a portable recording medium, supplies operating power to the portable recording medium, and exchanges information with the portable recording medium, the portable recording medium comprising: monitor the operating voltage supplied to the medium;
A portable recording medium reading/writing device comprising reset signal output means for outputting a reset signal to the portable recording medium when the operating voltage becomes less than a predetermined value.