JP2002368647A - Data carrier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a data carrier that can accurately conduct radio communication independently of a distance of an external radio communication unit. SOLUTION: The resistance of a variable resistance circuit D15 is selected by a 1st control signal, generated in a node N5 and produced by an internal circuit D4 and a 2nd control signal generated in a node N6, in response to a DC voltage, whether the resistance of the variable resistor is highest or other is detected by the control signals generated in the internal circuit, and the resistance, other than the highest resistance of the variable resistance circuit, is selected on the basis of a voltage level detection section of a DC voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data carrier such as an IC card and an IC-tag which perform communication in a non-contact state.

[0002]

2. Description of the Related Art In recent years, data carriers have been widely used as applications in which personal authentication and article management can be performed in a non-contact state.

FIG. 7 shows a conventional data carrier. Nodes N1 and N2 are first and second terminals of the resonance circuit D1, node N3 is an internal power supply node, and node N4 is an internal ground node. D4 is an internal circuit that generates a signal to be output from the data carrier to an external wireless communication device,
As a control signal.

As an element constituting the resonance circuit D1, a coil L1 for tuning a resonance frequency of a data carrier to a carrier frequency of a radio signal supplied from an external radio communication device is provided between nodes N1 and N2. A parallel resonance circuit of the capacitor C1 is provided.

The AC voltage obtained between the nodes N1 and N2 by the resonance circuit D1 is rectified by the rectifier circuit D2 to generate a DC voltage. The internal power supply potential on the high potential side is applied to the node N3, and the internal ground potential is applied to the node N4. Is output.

[0006] Between the nodes N3 and N4, this node N
A regulator D3 is provided to prevent the voltage between N3 and N4 from excessively increasing. Internal circuit D4
Operates using a voltage generated between the nodes N3 and N4 as a power supply, and executes writing / reading to / from an internal memory.

Between the nodes N1 and N2, there is provided a variable resistance circuit D5 for changing the resistance value to change the Q value of the parallel resonance circuit. FIG. 8 shows a variable resistance circuit D
5 is shown.

A variable resistor circuit D5 is formed by connecting a resistor R1, a control switch T1, and a resistor R2 in series between the nodes N1 and N2. The control switch T1 is P-MO
A negative logic switch composed of an S transistor. The gate electrode is connected to the node N5.

First, the carrier frequency output from the external radio communication device is received by the resonance circuit D1 so that the node N
The signal shown in FIG. 9A is generated between 1 and N2. FIG. 9B shows the voltage level between the nodes N3 and N4. In both figures, the horizontal axis shows the distance M between the wireless communication device and the data carrier, and the vertical axis shows the voltage level.

The area d in FIG. 9 is a case where the distance between the radio communication device and the data carrier is long and the regulator D3 is in the deactivation area. The magnetic field between the coil of the radio communication device and the coil of the data carrier is shown. The coupling is weak and node N3
Since the voltage difference between N4 is low, regulator 3 is in an inactive state.

When the distance between the wireless communication device and the data carrier is reduced and the magnetic coupling between the coils is increased, the voltage amplitude level between nodes N1 and N2,
Both the voltage level between 3 and N4 rises. When the distance between the wireless communication device and the data carrier is further reduced, the distance reaches the region C in FIG. 9 and increases to a voltage level at which the regulator D3 operates.

Even closer, the regulator D3 lowers the resistance value between the nodes N3 and N4, so that the internal circuit 4
Is maintained at a constant level between nodes N3 and N4.

FIG. 10A shows a node N5.
(B) shows that the regulator D3 operates at the node N in the inactive region
10C shows the voltage between the nodes N1 and N2 in the activation region of the regulator D3, and FIG. 10C shows the voltage between the nodes N1 and N2.

When the data carrier returns a response to the external wireless communication device, the internal circuit 4 outputs the content of the response to the node N5. Therefore, when the node N5 is at the “H” level, the resistance value of the data carrier is the nodes N1 and N1 excluding the coil L1, the capacitor C1, the resistors R1 and R2, and the control switch T1.
It becomes the resistance value seen from between two. Also, the node N5 is "L".
The resistance value of the data carrier at the time of level is determined by the resistors R1,
It becomes approximately equal to the series resistance value of R2 and the control switch T1.

Due to the change in the resistance value, the Q value of the data carrier changes, and the amplitude of the AC voltage between the nodes N1 and N2 also changes. The change in the amplitude is transmitted to the wireless communication device, and a response from the data carrier can be read.

[0016]

However, FIG. 10 (b)
In the case of, since the regulator D3 is in the inactive state,
The resistance between nodes N3 and N4 is high, and coil L1 and capacitance C
The resistance value between the nodes N1 and N2 except for 1 greatly depends on whether the control switch T1 of the variable resistance circuit D5 is connected or insulated.

Therefore, as shown by E in FIG.
The fluctuation of the AC voltage amplitude level between the nodes N1 and N2 becomes large, and the signal from the data carrier is easily received by the external wireless communication device. However, in the case of FIG. 10C, since the regulator 3 flows an electric current from the node N3 to the node N4 in the activated state, the resistance between the nodes N3 and N4 becomes low. Therefore, the resistance value between the nodes N1 and N2 excluding the coil L1 and the capacitance C1 does not depend much on whether the control switch T1 of the variable resistance circuit D5 is connected / insulated, and the node N1 indicated by F in FIG. , N2, the fluctuation of the AC voltage amplitude level is also reduced. As a result, there is a problem that it is difficult for an external wireless communication device to receive a signal from a data carrier at a short distance.

Further, since the communicable range between the wireless communication device and the data carrier depends on the resistance value of the variable resistance circuit D5, it is difficult to receive a signal from the data carrier after manufacturing the external wireless communication device. There is a problem that it is difficult to adjust.

The present invention solves the above-mentioned conventional problems. Even when the regulator D3 is in an activated state, wireless communication can be reliably performed, and the communication distance can be reduced after manufacturing. An object is to provide an excellent data carrier that can be adjusted.

[0020]

A data carrier according to the present invention receives an externally transmitted signal by an antenna circuit,
A data carrier that rectifies this and adjusts it with a regulator to cover required power and controls Q value control means for varying the Q value of the antenna circuit based on information read from an internal circuit to output data. Wherein the Q value control means is controlled based on the output of the regulator and information read from an internal circuit.

According to this configuration, the variation of the Q value of the resonance circuit in the data carrier for communication can be increased without depending on the distance between the data carrier and the external wireless communication device, and the wireless communication can be performed accurately. It can be carried out.

[0022]

The data carrier according to the first aspect of the present invention receives a signal transmitted from the outside by an antenna circuit, rectifies the signal and adjusts it by a regulator to cover required power, A data carrier that controls Q value control means for varying a Q value of the antenna circuit based on information read from an internal circuit and outputs data, wherein the Q value control means outputs the data from the output of the regulator and an internal circuit. It is characterized in that control is performed based on the read information.

According to a second aspect of the present invention, there is provided a data carrier comprising a resonance circuit comprising a coil and a capacitance, a rectifier connected between both terminals of the resonance circuit for converting into a DC voltage, and the resonance circuit. A Q value control means connected between both terminals of the resonance circuit to vary a Q value of the resonance circuit, a regulator for suppressing a rise in the potential of the DC voltage generated by the rectifier, and an internal circuit operated by an output of the regulator. And controlling the Q value control means based on information read from the internal circuit to output data, and controlling the Q value control means based on an output of the regulator. And

According to a third aspect of the present invention, in the data carrier according to the second aspect, the Q value control means is constituted by a variable resistance circuit connected in parallel to the resonance circuit, and the resistance value of the variable resistance circuit is controlled by the variable resistance circuit. It is configured to switch to three or more resistance values based on information read from an internal circuit and an output of the regulator.

According to a fourth aspect of the present invention, in the data carrier according to the third aspect, the resistance value of the variable resistance circuit is set as follows:
The switching is performed according to information read from the internal circuit and a voltage level detection signal of the regulator.

According to a fifth aspect of the present invention, in the data carrier according to the second aspect, the resistance value of the variable resistance circuit is switched by at least two control signals generated from an internal circuit.

According to a sixth aspect of the present invention, in the fifth aspect, at least one of the control signals is:
The determination is made with reference to the contents stored in the nonvolatile storage device.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
It will be described based on. (Embodiment 1) FIGS. 1 to 5 show (Embodiment 1) of the present invention.

FIG. 1 shows a data carrier according to the (first embodiment) of the present invention, and those having the same functions as those in FIG. A signal transmitted from the outside is received by a resonance circuit D1 as an antenna circuit, which is rectified and adjusted by a regulator to cover required power, and based on information read from an internal circuit 4, the antenna circuit Is a data carrier that controls the variable resistance circuit D15 as Q value control means for varying the Q value and outputs data. A regulator D3a is provided between the nodes N3 and N4. The regulator D3a includes a power supply voltage level detection circuit D16 and a regulator section D3b having the same configuration as the regulator D3 in FIG. 7 showing a conventional example.

The power supply voltage level detection circuit D16 observes whether the power supply voltage has risen to the voltage level at which the regulator D3a operates, and outputs the result to the node N6. Specifically, the power supply voltage level detection circuit D16 is configured as shown in FIG.

Further, FIG. 1 showing this (Embodiment 1)
In FIG. 7, the variable resistance circuit D5 in FIG. 7 showing the conventional example is changed to the variable resistance circuit D15 shown in FIG. The variable resistor circuit D15 includes a resistor R1 between the nodes N1 and N2.
1, R13, control switch T11 and resistor R14,
A series circuit with R12 is inserted, the gate of control switch T11 is connected to node N5, and the source-drain of control switch T12 is connected in parallel with resistor R13.
14 is connected in parallel with the source-drain of the control switch T13, and the gates of the control switches T12 and T13 are connected to a node N6 to which a signal is output from the power supply voltage level detection circuit D16.

The power supply voltage level detection circuit 16 shown in FIG. 3 is configured as follows. The reference voltage source D27 is
A reference voltage signal having a constant voltage level independent of the voltage difference between nodes N1 and N2 is generated and output to node N21.

The power supply voltage monitor circuit D28 is connected to the node N
A configuration in which a resistor 21 and a resistor 22 are connected in series between 3-N4 outputs a comparison power supply level signal that varies in proportion to the power supply voltage to a node N22.

The comparison circuit 29 compares the comparison power supply level signal generated at the node N22 with the reference voltage signal generated at the node N21. If the comparison power supply level signal at the node N22 is higher, the comparison circuit 29 connects to the node N6. Outputs a low level.

The variable resistor circuit D15 and the power supply voltage level detector D16 change the resistance value between the nodes N1 and N2 according to the logic of the nodes N5 and N6, so that the coil L1
The magnetic field is arranged for the purpose of giving a change to a magnetic field generated thereby and outputting information in a data carrier to an external wireless communication device.

More specifically, the first control switch T11 of the variable resistance circuit D15 is a negative logic switch composed of a P-MOS transistor, and insulates the nodes N1 and N2 when the node N5 is at "H" level. State, "L"
When the level is at the level, the nodes N1 and N2 are switched to the connection state.

The second control switches T12 and T13 are connected to P-
A negative logic switch composed of MOS transistors.
When the node N5 is at the “H” level, the nodes N1 and N2 are insulated regardless of the control signal 2, but when the node N5 is at the “L” level and the node N6 is at the “H” level, The resistance value of N1 and the node N2 is the resistance R
11, R13, conduction resistance of switch T11, resistor R1
4 and R12, and when the node N6 is at the "L" level, the resistance values of the nodes N1 and N2 are equal to those of the resistor R1.
1, the parallel connection resistance of the resistor R13 and the conduction resistance of the control switch T12, the conduction resistance of the control switch T11, the parallel connection resistance of the resistance R14 and the conduction resistance of the control switch T13, and the sum of the resistance R12.

That is, the node N5 selects between the insulated state and the connected state, and the node N6 controls the resistance value in the connected state. First, the operation of the power supply voltage level detector 16 will be described.

FIG. 4A shows a voltage level VCC generated between nodes N3 and N4, a reference voltage signal generated at node N21, and a comparison power supply level signal generated at node N22. b) shows the output waveform of the second control signal generated at the node N6 at that time, where the horizontal axis shows the power supply voltage and the vertical axis shows the voltage level.

When the voltage level VCC generated between nodes N3 and N4 is a low voltage, the comparison power supply level signal is VC
As C rises, it rises and approaches the voltage level of the reference voltage signal. At this time, the comparison circuit D29 outputs “H” logic at the same level as VCC as the second control signal generated at the node N6.

When VCC is gradually increased, when the comparison power supply level signal becomes higher than the voltage level of the reference voltage signal, the comparison circuit 29 outputs the second control signal generated at the node N6 at the same level as VSS. L ”logic is output.

In the power supply voltage level detecting section 16, the voltage level of the VCC at which the comparison result switches is set to the same potential as the voltage level at which the regulator section D3b of FIG. 1 operates.

Referring to FIG. 5, the operation of a response from the data carrier to the wireless communication device in the data carrier having the configuration shown in FIGS. 1 to 3 will be described. 5A shows a first control signal generated at the node N5, and FIG. 5B shows a voltage amplitude between the nodes N1 and N2 when the communication distance between the external wireless communication device and the data carrier is long. (C) shows the voltage amplitude between the nodes N1 and N2 when the communication distance between the external wireless communication device and the data carrier is short, the horizontal axis shows time T, and the vertical axis shows the voltage level. .

When the communication distance between the external radio communication apparatus and the data carrier is short, the VCC level is high, so the second control signal generated at the node N6 becomes "L" logic, and when it is far, the VCC level is low. Therefore, the logic becomes "H".

In the case of FIG. 5B, since the regulator unit 3 is in the inactive state, the resistance between the nodes N3 and N4 is high, and the resistance between the nodes N1 and N2 excluding the coil L1 and the capacitance C1 is This largely depends on whether the control switch T11 as the first control switch of the variable resistance circuit 5 is connected or insulated.

Therefore, the ratio of the fluctuation of the AC voltage amplitude level between the nodes N1 and N2 (E in FIG. 5B) increases, and the signal from the data carrier is easily received by the external wireless communication device.

As shown in FIG. 5C, when a current flows from the node N3 to the node N4 in a state where the regulator section D3b is activated and the resistance between the nodes N3 and N4 is reduced, the voltage is generated at the node N6. Since the second control signal has the “L” logic, the control switches T12 and T13 as the second control switches are turned on.

Therefore, the resistance value of the variable resistance circuit 5 with the control switch T11 connected is lower than when the regulator 3 is in the inactive state, and the fluctuation of the AC voltage amplitude level between the nodes N1 and N2 ( In F) of FIG. 5 (c), a sufficient difference is secured, and an excellent data carrier capable of reliably performing communication between the data carrier and the external wireless communication device even when the regulator unit 3 is operating can be realized.

(Embodiment 2) FIG. 6 shows a data carrier according to (Embodiment 2) of the present invention.
Except for the power supply voltage level detection unit D16 in (Embodiment 1), the second control signal of the node N6 is generated from the internal circuit D4 in the same manner as the first control signal of the node N5. I have.

The second control signal read from the internal circuit D4 is data stored in the nonvolatile memory element in advance, and "H" logic or "L" logic is written for each product.

When the second control signal read from the internal circuit D4 is "H" logic, the resistance value of the variable resistance circuit D15 when the first control signal is "L" logic is high. The set current flowing through the variable resistance circuit D15 decreases. Therefore, even when the communication distance between the external wireless communication device and the data carrier is long and the first control signal is “L” logic, it is possible to realize a data carrier for long-distance communication with minimal loss.

When the second control signal read from the internal circuit D4 is "L" logic, the resistance value of the variable resistance circuit D15 is set low when the first control signal is "L" logic. As a result, the current flowing through the variable resistance circuit D15 increases. In other words, when the first control signal has the “L” logic, the current consumption is large, so that it is not suitable for long-distance communication. However, as is clear from the description of (Embodiment 1), when the communication distance between the external wireless communication device and the data carrier is short,
A data carrier that can reliably communicate can be realized.

As described above, by storing the data of the second control signal in the nonvolatile storage device, a data carrier having an arbitrary communicable distance can be realized. Note that the description of the nonvolatile memory device in this (Embodiment 2) refers to a memory which can continue to hold written data even when the power supply voltage is lost. It can be composed of any memory that cannot be rewritten dynamically.

In the above embodiment, the resistance value of the variable resistance circuit is switched based on the two signals at the nodes N5 and N6 read from the internal circuit D4. By using a plurality of data stored in the nonvolatile storage device and using the data as the third and subsequent control signals, the resistance value of the variable resistance circuit can be more finely controlled. Fluctuations can be reduced.

[0055]

As described above, according to the data carrier of the present invention, an excellent data carrier which can easily communicate regardless of the distance between the data carrier and an external wireless communication device can be realized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a data carrier according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a variable resistance circuit D15 according to the embodiment.

FIG. 3 is a power supply voltage level detection unit D according to the embodiment;
Configuration diagram of 16

FIG. 4 is a power supply voltage characteristic of a power supply voltage level detection circuit D16 according to the embodiment.

FIG. 5 is a diagram illustrating a difference between a distance between the wireless communication apparatus and a data carrier and an output waveform of a reply signal according to the embodiment.

FIG. 6 is a configuration diagram of a data carrier according to (second embodiment) of the present invention.

FIG. 7 is a configuration diagram of a conventional data carrier.

FIG. 8 is a configuration diagram of a variable resistor circuit in the conventional example.

FIG. 9 is a diagram showing the relationship between the distance between the wireless communication device and the data carrier and the voltage level between each node in the data carrier of the conventional example.

FIG. 10 is a diagram showing the difference between the distance between the wireless communication device and the data carrier and the output waveform of the reply signal in the data carrier of the conventional example.

[Explanation of symbols]

L1 coil C1 capacitor N1 node at one end of resonance circuit N2 node at one end of resonance circuit N3 internal power supply node N4 internal ground node N5 node where first control signal is generated N6 node where second control signal is generated N21 reference voltage Node that generates N22 Node that generates a power supply level signal for comparison D1 Resonance circuit D2 Rectifier D3a Regulator D3b Regulator section D4 Internal circuit D15 Variable resistance circuit D16 Power supply voltage level detection section D27 Reference voltage generation source D28 Power supply voltage monitor circuit D29 Comparison circuit T1 Control switch T11 Control switch T12 Control switch T13 Control switch R11, R12, R13, R14, R21, R22
resistance

Claims (6)

[Claims] An antenna circuit receives a signal transmitted from the outside, rectifies the signal and adjusts the signal by a regulator to cover the required power, and based on information read from an internal circuit, a signal of the antenna circuit. What is claimed is: 1. A data carrier which controls a Q-value control means for changing a value and outputs data, wherein the data carrier is configured to control the Q-value control means based on an output of the regulator and information read from an internal circuit. 2. A resonance circuit comprising a coil and a capacitance; a rectifier connected between both terminals of the resonance circuit for converting into a DC voltage; and a resonance circuit connected between both terminals of the resonance circuit. Q-value control means for varying the Q-value of the rectifier; a regulator for suppressing an increase in the potential of the DC voltage generated by the rectifier; and an internal circuit operated by the output of the regulator, and Said Q based on the information
A data carrier configured to control value control means to output data and to control the Q value control means based on an output of the regulator. 3. The Q value control means comprises a variable resistance circuit connected in parallel to the resonance circuit, and determines a resistance value of the variable resistance circuit based on information read from the internal circuit and an output of the regulator. 3. The data carrier according to claim 2, wherein the data carrier is configured to switch to one or more resistance values. 4. A data carrier according to claim 3, wherein a resistance value of said variable resistance circuit is switched by information read from said internal circuit and a voltage level detection signal of said regulator. 5. The data carrier according to claim 2, wherein the resistance value of the variable resistance circuit is switched by at least two control signals generated from an internal circuit. 6. The data carrier according to claim 5, wherein at least one of the control signals is determined by referring to contents stored in a nonvolatile storage device.