JPH08315092A - Non-contact ic card - Google Patents

Abstract

PURPOSE: To extend the life of a battery built in a card body as long as possible by detecting a voltage change in the battery through a switch means and setting up a transmitting means to a driven state based upon the detected voltage change. CONSTITUTION: When an antenna (a) of a non-contact IC card body 1 receives a radio wave from a transmitter T, a transmitting circuit 5 supplies a prescribed signal to the antenna (a) and data transmission/reception between the transmitter T and the IC card body 1 is executed. After completing the transmission/ reception of prescribed data, a non-contact type automatic ticket examination machine ends a series of arithmetic processing based upon card data received from the body 1, completes the writing of prescribed entrance/exit data in a memory of a CPU 4 built in the body 1, detects the voltage change of the battery 2 through the switch means of a detection circuit 10 and turns off power supply from the battery 2 to the circuit devices of the body 1. Thereby the life of the battery 2 can be extended.

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 used in, for example, a non-contact type automatic ticket gate, and more particularly to a non-contact type IC card for reducing power consumption and extending the life of the card.

[0002]

2. Description of the Related Art When a contactless IC card is used as a commuter pass, the unit price of the card is higher than that of a magnetic card. Used across.

However, although the data can be updated many times, when the battery built in for driving the non-contact IC card body (hereinafter referred to as the IC card body) has run out, that is, the battery is When the voltage drops to such an extent that the card body cannot be driven, it cannot be used as a commuter pass.

As described above, the life of the non-contact IC card depends on the life of the built-in battery. Therefore, the carrier sampling method has been proposed to extend the life of the battery.

In this carrier sampling method, for example, two kinds of oscillators having a low frequency of 32 KHz and a high frequency of 4 MHz are provided in the card body, and normally, they are operated at a low frequency to reduce power consumption. At predetermined intervals,
For example, sampling of the presence / absence of a carrier is performed at intervals of 10 msec. Then, in the carrier sampling, when a carrier is detected, the frequency is changed to a high frequency to communicate with the main body of the automatic ticket gate.

[0006]

However, in the above-mentioned conventional non-contact card, even if the carrier sampling method is adopted to extend the life of the battery, the cost and performance are not sufficient, and further improvement is required. Was wanted.

That is, when the above-mentioned carrier sampling method is adopted, two types of oscillators are required, resulting in high cost, and a low-frequency oscillator is composed of a crystal oscillator, so that there is a problem in mechanical strength. there were.

Further, even if the above-mentioned carrier sampling method is adopted, the low frequency oscillator is always in the operating state like the commuter pass even though the communication time in one day is extremely short. However, there is a drawback that it consumes unnecessary power.

Therefore, the present invention was made in order to solve the above-mentioned drawbacks, and its purpose was to pay attention to the form of use of a non-contact card. It is to provide a contactless card that can have a long life as long as possible.

[0010]

A non-contact IC according to the present invention
In order to achieve the above object, the card is an IC card equipped with a transmitting unit that is driven by a power source of a battery provided in the IC card main body and transmits predetermined data stored in the memory. Receiving means for receiving a predetermined signal from outside the main body, switch means for operating when the receiving means receives the predetermined signal, and detecting means for detecting a voltage change of the battery through the switch means. And setting means for setting the transmitting means to an operating state based on a voltage change of the detecting means when the switch means receives a predetermined signal and operates.

Further, in an IC card equipped with a transmitting means for transmitting predetermined data stored in the memory by being driven by a power source of a battery provided in the IC card main body, Receiving means for receiving the signal, n-fold voltage rectifying means for rectifying the signal voltage received by the receiving means by n-fold voltage, and the transmitting means are put into operation based on the output signal from the n-fold voltage rectifying means. It is characterized by having setting means for setting.

[0012]

In the above construction, the setting means sets the transmitting means to the operating state based on the voltage change of the detecting means when the switch means receives a predetermined signal and operates.

The setting means sets the transmitting means to an operating state based on the output signal from the n-fold voltage rectifying means.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram when an IC card according to an embodiment is used as a commuter pass for a non-contact type automatic ticket gate,
Oscillation circuit 3 driven by the power supply of battery 2, CPU 4,
A transmission circuit 5 and a reception circuit 6 are provided.

The receiving circuit 6 receives a signal transmitted from an antenna A of a transmitter T provided in a non-contact type automatic ticket gate (not shown) with an antenna a, performs a detection process and a demodulation process, and outputs it to the CPU 4. Is configured to.

The CPU 4 is constructed so as to be able to store the signal (data) received from the receiving circuit 6 in a memory (not shown) and also to control the IC card body 1 as a whole.

The CPU 4 divides the frequency generated by the oscillation circuit 3 to obtain a signal of, for example, 500 KHz, which is sufficiently lower than the frequency (for example, 2.45 GHz) of the signal (main carrier) from the transmitter T side. It is configured such that (subcarrier) is generated, and card data stored in the memory, such as a boarding section, is modulated by the transmission circuit 5 and can be fed to the antenna a. Therefore, when the antenna a is reflected by the main carrier wave that is transmitted from the antenna A of the transmitter T in a time-division manner and is transmitted, the phase is just modulated by the card data. Therefore, by receiving this reflected wave on the transmitter T side, the contactless automatic ticket gate can perform a predetermined arithmetic process for the ticket gate processing based on the card data.

The CPU 4 is constantly supplied with the power of the battery 2 and holds the stored contents of the memory provided in the CPU 4. However, since the power consumption of holding the stored contents of this memory is extremely small, the influence on the life of the card can be ignored.

The oscillating circuit 3, the CPU 4, the transmitting circuit 5 and the receiving circuit 6 are constructed so that the driving is started when the CPU 4 receives an interrupt signal from a detecting circuit 10 which will be described later.

The details of the detection circuit 10 are shown in FIG. 2, which has a switching element composed of a field effect transistor (hereinafter referred to as FET), and the drain (D) side of the FET has two resistors R1 and R2. Is connected in series to the power supply voltage VDD side of the battery 2. Then, both resistors R
An interrupt signal, which is a signal for starting the drive of the CPU 4, can be taken out from the middle of 1 and R2.

The source (S) of the FET is a diode D0
And the slot antenna a are grounded in series, and the gate (G) side of the FET has a resistor R3 and a plurality of diodes D connected in series between the power supply voltage VDD and ground.
It is connected between 1 and Dn.

Therefore, when a signal is externally received by the slot antenna a ', that is, the IC card body (commuter pass) 1 is held over the non-contact type automatic ticket gate, and the slot antenna a'has an antenna A of the transmitter T. When a radio wave is received from the FET, the voltage between the G and S of the FET becomes equal to or higher than a predetermined threshold value (threshold value) and is turned on, and a current flows between D and S. Due to this current flow,
As for the interrupt signal, the predetermined voltage which has been maintained at the power supply voltage VDD of the battery 2 until now becomes 0 volt. CPU4 is this 0
The oscillator circuit 3, the transmitter circuit 5, and the receiver circuit 6 are driven as well as being driven by receiving power from the battery 2 based on the voltage signal.

The above-mentioned interrupt signal is adjusted by the resistor R2 so as not to have a negative value. Also,
The diodes D1 to Dn are adjusted so that the gate voltage can be maintained at a predetermined constant voltage. Therefore, for example, when the battery 2 is a 3V lithium battery and the operation of the CPU 4 can be performed at 2.2V or more, the power supply voltage VDD is 2.2 to 3.2V due to the diodes D1 to Dn.
Even if it changes to some extent, the switching operation of the FET can be stabilized.

The slot antenna a'is the transmitter T
When a predetermined signal is received from the transmitter T side when the oscillation circuit 3, the CPU 4, the transmission circuit 5 and the reception circuit 6 are driven by receiving a radio wave from the side, the transmission circuit 5 supplies the predetermined signal to the antenna a. Then, data is exchanged between the transmitter T and the IC card body 1.
Then, when the predetermined data transfer is completed, that is, a series of arithmetic processing based on the card data received from the IC card body 1 by the non-contact automatic ticket gate is completed, and the memory of the CPU 4 of the IC card body 1 is completed. When the writing of the predetermined entrance / exit data is completed, the power supply from the battery 2 to the oscillation circuit 3, the CPU 4, the transmission circuit 5, and the reception circuit 6 is cut off.

Therefore, in the non-contact IC card according to this embodiment, when a series of data transfer is completed,
Since power supply to the oscillation circuit 3, the CPU 4, the transmission circuit 5, and the reception circuit 6 is cut off, the consumption of the battery 2 can be reduced and the life of the card can be extended.

FIG. 3 shows another example of the detection circuit 20 of the detection circuit 10 described above, in which the signal received by the slot antenna a'is processed by a known n-fold voltage rectification circuit 21,
The signal from the n-fold voltage rectifier circuit 21 is used as an interrupt signal to start driving the CPU 4.

That is, the n-fold voltage rectifier circuit 21 is
A weak current generated when the slot antenna a'receives a radio wave transmitted from the transmitter T side is amplified and formed into an interrupt signal of the CPU 4.

In FIG. 3, reference numerals 22 and 23 denote switches controlled by the CPU 4. Here, the sleep state means that the transmitter T side is not communicating.

[0029]

The contactless IC card according to the present invention is an IC
Receiving means for receiving a predetermined signal from outside the card body,
A switch means that operates when the receiving means receives a predetermined signal, a detecting means that detects a voltage change of the battery through the switch means, and the switch means operates by receiving a predetermined signal. And a setting unit that sets the transmitting unit to an operating state based on a voltage change of the detection unit at that time, so that power is consumed only when a signal is received from the outside, and battery power consumption can be reduced. it can.

Further, the non-contact IC card according to the present invention,
Based on receiving means for receiving a predetermined signal from outside the IC card main body, n-fold voltage rectifying means for rectifying the signal voltage received by the receiving means by n-fold voltage, and an output signal from the n-fold voltage rectifying means. Since the transmitting means is set to the operating state, the power is consumed only when a signal is received from the outside, and the power consumption of the battery can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram when a contactless IC card according to an embodiment of the present invention is used as a commuter pass for a contactless automatic ticket gate.

FIG. 2 is a detailed diagram of a detection circuit.

FIG. 3 is a detailed view of another example of the detection circuit.

[Explanation of symbols]

 1 Non-contact IC card body (IC card body) 2 Battery 3 Oscillation circuit 4 CPU 5 Transmission circuit 6 Reception circuit a, A Antenna 10, 20 Detection circuit T Transmitter

Claims (2)

[Claims] 1. A non-contact IC card including a transmission unit that is driven by a power source of a battery provided in the non-contact IC card main body and transmits predetermined data stored in a memory. Receiving means for receiving a predetermined signal from outside the main body, switch means for operating when the receiving means receives the predetermined signal, and detecting means for detecting a voltage change of the battery through the switch means. A contactless IC card, which includes: setting means for setting the transmitting means to an operating state based on a voltage change of the detecting means when the switch means receives a predetermined signal and operates. . 2. A non-contact IC card comprising a transmission means for transmitting predetermined data stored in a memory by being driven by a power source of a battery provided in the non-contact IC card body. Receiving means for receiving a predetermined signal from outside the main body, and n for rectifying the signal voltage received by the receiving means by n times
A non-contact IC card comprising: a voltage doubler rectifying unit; and a setting unit that sets the transmitting unit to an operating state based on an output signal from the n-fold voltage rectifying unit.