JP2007140903A - Noncontact data carrier - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To supply a stable power supply voltage even if the electric power received by a coiled antenna varies as the result of the load modulation of a noncontact data carrier itself. <P>SOLUTION: The noncontact data carrier includes a parallel resonant circuit 1 consisting of a coiled antenna 1a and a tuning capacitor 1b; a power supply system circuit A which produces a power supply voltage from an AC voltage obtained from the parallel resonant circuit 1; and a communication system circuit B connected to the parallel resonant circuit 1 for generating clocks and demodulating and modulating information data. The power supply system circuit A includes a rectifying circuit 2 for converting AC signals received by the coiled antenna 1a into DC voltages; a booster circuit 3 for boosting the output voltage of the rectifying circuit 2; a booster circuit regulator 5 for regulating the output voltage of the booster circuit 3 with a voltage reference created from the output of the rectifying circuit 2; and a digital circuit regulator 10 for regulating the output voltage of the booster regulator 5 to suit a digital circuit 16. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a non-contact data carrier that is used for various ID confirmations, financial transactions, merchandise management, and the like and does not require an electrical contact by an electromagnetic inductive coupling method and performs wireless communication with a reader / writer.

  In recent years, development of a non-contact data carrier that does not have an electrical contact, supplies a power supply voltage using an electromagnetic inductive coupling method, etc., and simultaneously transmits and receives data has been promoted. Unlike data carriers such as magnetic cards and contact-type IC cards, non-contact data carriers have no contact points, so there is no communication failure due to corrosion, dirt, or contact wear, and resistance to static electricity and water. At the same time, the reader / writer does not require any contact or data carrier insertion / extraction mechanism and is maintenance-free. In addition, from the viewpoint of memory capacity and security, a large market is expected in the fields of personal ID or logistics and product management.

  An outline of the conventional technology related to the non-contact data carrier will be described with reference to FIG.

  FIG. 7 is a block diagram showing the main configuration of a contactless data carrier in the prior art. A contactless data carrier for transmitting information data and power by wireless communication with a reader / writer (not shown) includes a coiled antenna 1a for transmitting and receiving radio waves, a parallel resonant circuit 1 including a tuning capacitor 1b, and a coiled antenna. A power supply system circuit A that rectifies an AC voltage generated at both ends of 1a and outputs a DC voltage, and a communication system circuit that generates a clock from the AC voltage generated at both ends of the coiled antenna 1a, extracts a signal component, and transmits a signal B, an analog circuit 11 that performs analog processing, a digital circuit 16 that performs digital processing, a memory 17 that stores information, the power supply system circuit A, the communication system circuit B, the analog circuit 11, the digital circuit 16, and the memory described above. 17, the CPU 18 controls each operation so that each functions well. A modulation transistor 15 is connected between the output terminals of the parallel resonant circuit 1. The power circuit A includes a rectifier circuit 2 that rectifies an AC voltage generated at both ends of the coiled antenna 1a and outputs a DC voltage, and a regulator 10a that further stabilizes the rectified DC voltage and supplies the rectified DC voltage to the digital circuit 16. Yes. The communication system circuit B includes a clock generation circuit 12 that generates a clock from a carrier wave component included in an AC voltage generated at both ends of the coiled antenna 1a, and a demodulation circuit 13 that extracts a reception data component included in the AC voltage. In response to transmission data from the digital circuit 16, the modulation transistor 15 is turned on / off, and the modulation circuit 14 performs AM modulation by changing the load between the terminals of the coiled antenna 1a. The DC voltage output from the rectifier circuit 2 in the power system A is supplied to the analog circuit 11, and the adjusted power supply voltage output from the regulator 10 a is supplied to the digital circuit 16. The clock generated by the clock generation circuit 12 in the communication system circuit B is supplied to the digital circuit 16, and the demodulated signal from the demodulation circuit 13 is supplied to the digital circuit 16. The memory 17 and the CPU 18 are connected to the digital circuit 16. The CPU 18 controls each unit via the digital circuit 16, and the CPU 18 and the digital circuit 16 store data in the memory 17 and read out necessary data from the memory 17 in the course of processing. In order to efficiently transmit and receive radio waves to and from the reader / writer, the parallel resonant circuit 1 has constants of the coiled antenna 1a and the tuning capacitor 1b so that the resonant frequency matches the frequency of the carrier wave of the information signal and the response signal. Is stipulated.

  Next, the operation of the non-contact data carrier in the conventional technique configured as described above will be described.

  Information data and power transmitted from a reader / writer (not shown) are received by the parallel resonant circuit 1 and converted into a DC voltage by the rectifier circuit 2 in the power supply system circuit A. The rectified voltage is supplied to the analog circuit 11, the power supply voltage is adjusted for the digital circuit 16 by the regulator 10 a, and the digital circuit 16 is supplied with power. On the other hand, in the communication system circuit B, the clock generation circuit 12 generates a clock from the AC voltage received by the parallel resonance circuit 1, and the demodulation circuit 13 extracts received data by envelope detection. The modulation circuit 14 AM-modulates the information data from the digital circuit 16, drives the modulation transistor 15 with the modulation signal, switches the load between the terminals of the coiled antenna 1a, and wirelessly transmits the information data to the reader / writer. .

Further, Patent Document 1 includes two rectifier circuits, one rectifier circuit connected to a power supply system circuit, and the other rectifier circuit connected to a communication system circuit, thereby separating the power supply and the load modulation unit. A non-contact data carrier is disclosed.
JP 11-250210 A (page 3-4, FIG. 1-2)

  However, in the conventional non-contact data carrier as described above, when the non-contact data carrier itself performs AM modulation, the resonance frequency of the parallel resonance circuit 1 is changed by switching the load between both terminals of the coiled antenna 1a. The reception sensitivity at the antenna changes, and the reception power from the reader / writer fluctuates. As a result, the DC voltage output from the rectifier circuit 2 also changes at the same time, and the supply voltage to the digital circuit 16 generated from the DC voltage via the regulator 10a also changes. There are problems that malfunctions occur due to such fluctuations in the power supply and that the operation becomes unstable because sufficient power is not obtained for the operation.

  Further, in the case of the non-contact data carrier of Patent Document 1, even if the fluctuation of the power source due to load modulation can be suppressed to some extent, the parallel rectifier circuit is connected in common to the two rectifier circuits, so that the modulation is shallow. If so, the communication characteristics deteriorate, and if the modulation becomes deeper, the trade-off relationship in which the power source fluctuates greatly does not change.

  The present invention solves the above-mentioned conventional problems, and a non-contact data carrier that can supply a stable power supply voltage even if the received power of the coiled antenna changes due to load modulation of the non-contact data carrier itself. The purpose is to provide.

A contactless data carrier according to the present invention comprises:
A parallel resonant circuit consisting of a coiled antenna and a tuning capacitor;
A power supply system circuit that is connected to the parallel resonant circuit and generates a power supply voltage from an AC voltage obtained by the parallel resonant circuit;
A communication system circuit connected to the parallel resonant circuit for generating a clock, demodulating and modulating information data;
The power supply circuit is
A rectifier circuit that converts an AC signal received by the coiled antenna of the parallel resonant circuit into a DC voltage;
A booster circuit for boosting the output voltage of the rectifier circuit;
A regulator for a booster circuit that regulates an output voltage of the booster circuit based on a voltage reference generated from an output of the rectifier circuit;
And a digital circuit regulator for regulating the output voltage of the boost regulator for a digital circuit.

  In this configuration, if load modulation is performed in the parallel resonant circuit by the operation of the communication system circuit, fluctuations in the received power in the parallel resonant circuit occur and the output voltage of the rectifier circuit decreases. Thus, a voltage sufficiently higher than the voltage level required by the analog circuit is obtained. Then, the output voltage of the booster circuit is regulated (stabilized to a predetermined voltage value) by the booster circuit regulator and adjusted to a predetermined voltage level required by the analog circuit. Further, the regulated power supply voltage is input to the digital circuit regulator and the analog circuit. According to this configuration, even if the received power in the parallel resonant circuit fluctuates due to load modulation of the non-contact data carrier itself, a stable power supply voltage can always be obtained.

  In the above-described configuration, the first switching element interposed between the output terminal of the rectifier circuit and the input terminal of the digital circuit regulator and the analog circuit, the output terminal of the rectifier circuit, and the booster circuit And a second switching element interposed between the input terminal of the regulator for the booster circuit, and the both switching elements are on / off controlled by a transmission flag signal output from the digital circuit. There is a mode in which the booster circuit is operated only during modulation.

  According to this configuration, in a period in which load modulation is not performed, the first switching element is turned on by the transmission flag signal from the digital circuit, the rectifier circuit is connected to the digital circuit regulator, and the second switching element is turned off. The booster circuit and the regulator for the booster circuit are separated from each other so as not to operate. Power consumption is suppressed by disabling the booster circuit and the booster regulator. On the other hand, during the period of load modulation, the second switching element is turned on to operate the booster circuit, and the first switching element is turned off. The booster circuit and booster circuit regulator are operated during the load modulation period, which is a major cause of fluctuations in received power in the parallel resonant circuit, but the booster circuit and booster circuit regulator are disabled during other periods. Therefore, power consumption can be effectively suppressed.

  In the above-described configuration, the transmission flag output from the digital circuit is further provided with a third switching element between the output terminal of the booster circuit regulator and the input terminal of the digital circuit regulator and the analog circuit. There is a mode in which the third switching element is on / off controlled with respect to the first switching element by a signal.

  According to this, during the period when the load modulation is not performed, the current flowing into the booster circuit regulator is cut off by disconnecting the output side of the booster circuit and the booster circuit regulator from the digital circuit regulator. It is possible to further stabilize the power supply voltage.

  Further, in the above configuration, there is a mode in which a delay circuit that further delays a transmission flag signal from the digital circuit for the first switching element and the third switching element is provided.

  According to this, the second switching element is turned on, the booster circuit and the booster circuit regulator are switched to the operating state, the operation of the booster circuit is stabilized, and the output voltage rises and stabilizes. One switching element is turned off, and the third switching element is turned on. Therefore, the step-up function of the step-up circuit is efficiently added to the digital circuit regulator and the analog circuit.

Further, the contactless data carrier according to the present invention is:
A parallel resonant circuit consisting of a coiled antenna and a tuning capacitor;
A power supply system circuit that is connected to the parallel resonant circuit and generates a power supply voltage from an AC voltage obtained by the parallel resonant circuit;
A communication system circuit connected to the parallel resonant circuit for generating a clock, demodulating and modulating information data;
The power supply circuit is
A rectifier circuit that converts an AC signal received by the coiled antenna of the parallel resonant circuit into a DC voltage;
A digital circuit regulator for regulating the output voltage of the rectifier circuit for a digital circuit;
A booster circuit for boosting the output voltage of the rectifier circuit;
A switching element for cutting off supply of the output voltage of the booster circuit to the regulator for the digital circuit and the analog circuit;
A first voltage detection circuit that detects a voltage level of an output of the booster circuit and stops the operation of the booster circuit when exceeding a predetermined level;
A second voltage detection circuit that detects a voltage level of the output of the rectifier circuit and conducts the switching element when the voltage level is lower than a predetermined level, and shuts off the switching element when the voltage level exceeds the predetermined level;

  According to this configuration, the output voltage of the rectifier circuit is constantly supplied to the digital circuit regulator and the analog circuit. The first voltage detection circuit monitors the output voltage of the booster circuit. When the voltage is lower than a predetermined level, the booster circuit is operated. When the predetermined voltage is exceeded, the booster circuit is stopped to stabilize the output voltage of the booster circuit. And reducing unnecessary power consumption. On the other hand, the second voltage detection circuit monitors the output voltage of the rectifier circuit. When the output voltage is lower than a predetermined level, the switching element is switched to the conductive state and the booster circuit is connected to the digital circuit regulator and the analog circuit. The boosted voltage stabilized by the circuit and the first voltage detection circuit is supplied to the digital circuit regulator and the analog circuit. In this way, power consumption can be suppressed by operating the booster circuit only when necessary while stabilizing the power supply voltage.

  Further, in the above, there is a mode in which a smoothing capacitor inserted between the output terminal of the booster circuit and the ground is further provided. According to this, since the voltage level after boosting by the boosting circuit is smoothed, the power supply voltage can be further stabilized.

  Furthermore, in the above configuration, the parallel resonant circuit is a first parallel resonant circuit, and a second parallel resonant circuit is provided separately from the first parallel resonant circuit, and the communication system circuit includes the first parallel resonant circuit. There is a mode in which it is disconnected from the circuit and connected to the second parallel resonant circuit instead. That is, two parallel resonance circuits each including a coiled antenna and a tuning capacitor are provided, one connected to a power supply system circuit and the other connected to a communication system circuit.

  According to this configuration, the output of the first parallel resonant circuit serving as the input of the power supply system circuit and the output of the second parallel resonant circuit serving as the input of the communication system circuit are independent of each other. As a result of switching and modulating the load of the second parallel resonant circuit to which the circuit is connected, even if the received power fluctuates, the first parallel resonant circuit to which the power system circuit is connected may be directly affected. Therefore, a more stable power supply voltage can be obtained.

  As described above, according to the present invention, in response to fluctuations in the rectified voltage caused by load modulation of the non-contact data carrier itself, the output voltage of the rectifying circuit that fluctuates is boosted, and the boosted voltage is increased by a regulator. A stable power supply voltage can be obtained by suppressing the voltage level. By stabilizing the power supply, it is possible to eliminate malfunctions due to power supply fluctuations and unstable characteristics, and to provide a highly reliable contactless data carrier.

  In addition to power fluctuations due to load modulation, the distance between the reader / writer and the non-contact data carrier changes rapidly, and the presence of multiple non-contact data carriers in the communicable area of the reader / writer allows the parallel resonant circuit to Stabilizes the power supply voltage against power fluctuations in usage environments where the resonance frequency or reception sensitivity changes, or the resonance frequency or reception sensitivity of the parallel resonant circuit changes due to the presence of metal near the non-contact data carrier. Exhibits excellent effects.

  In addition, since the boosted power supply voltage is used, it is possible to perform communication farther from the reader / writer than in the past.

  Embodiments of a non-contact data carrier according to the present invention will be specifically described below with reference to the drawings.

(Embodiment 1)
The non-contact data carrier in Embodiment 1 of this invention is demonstrated.

  FIG. 1 is a block diagram showing a main configuration of a contactless data carrier according to Embodiment 1 of the present invention. In FIG. 1, a non-contact data carrier for transmitting information data and power by wireless communication with a reader / writer (not shown) includes a parallel resonant circuit 1, a power supply system circuit A, a communication system circuit B, an analog circuit 11, and a digital circuit. The circuit 16, the memory 17, and the CPU 18 are included.

  The parallel resonant circuit 1 is composed of a parallel circuit of a coiled antenna 1a and a tuning capacitor 1b. Information data and power transmitted from the reader / writer are received by the coiled antenna 1a and the tuning capacitor 1b, and become an AC voltage signal. The power supply system circuit A and the communication system circuit B are connected to the parallel resonance circuit 1.

  The power supply circuit A includes a rectifier circuit 2, a booster circuit 3, a booster circuit regulator 5 and a digital circuit regulator 10. The rectifier circuit 2 is connected to the output terminal of the parallel resonance circuit 1, and rectifies the AC voltage obtained by the parallel resonance circuit 1 to convert it into a DC voltage. A booster circuit 3 and a booster circuit regulator 5 are inserted between the output terminal of the rectifier circuit 2 and the input terminals of the digital circuit regulator 10 and the analog circuit 11, and a smoothing capacitor is connected between the output terminal of the booster circuit 3 and the ground. 4 is connected. The booster circuit regulator 5 includes a reference voltage generation circuit 6, a comparator 7, a switching element 8, and voltage detection voltage dividing resistors 9a and 9b. The switching element 8 is composed of a P-channel MOS transistor, and is inserted between the output terminal of the booster circuit 3 and the input terminals of the digital circuit regulator 10 and the analog circuit 11. The input terminal of the reference voltage generation circuit 6 is connected to the output terminal of the rectifier circuit 2, and the output terminal of the reference voltage generation circuit 6 is connected to the inverting input terminal (−) of the comparator 7. Voltage dividing resistors 9a and 9b are inserted between a connection point between the switching element 8, the digital circuit regulator 10 and the analog circuit 11 and the ground. The resistance dividing points of the voltage dividing resistors 9 a and 9 b are connected to the non-inverting input terminal (+) of the comparator 7.

  The communication system circuit B includes information from the clock generation circuit 12 that generates a clock from the AC signal obtained by the parallel resonance circuit 1, the demodulation circuit 13 that extracts received data from the AC signal by envelope detection, and the information from the digital circuit 16. It comprises a modulation circuit 14 that AM modulates data. A modulation transistor 15 is connected between the output terminals of the parallel resonant circuit 1. The transistor 15 is composed of a P-channel MOS transistor, and the output terminal of the modulation circuit 14 is connected to the gate thereof.

  The adjusted power supply voltage output from the digital circuit regulator 10 in the power supply circuit A is supplied to the digital circuit 16. The clock generated by the clock generation circuit 12 in the communication system circuit B is supplied to the digital circuit 16, and the demodulated signal from the demodulation circuit 13 is supplied to the digital circuit 16. The memory 17 and the CPU 18 are connected to the digital circuit 16. The CPU 18 controls each unit via the digital circuit 16, and the CPU 18 and the digital circuit 16 store data in the memory 17 and read out necessary data from the memory 17 in the course of processing.

  Next, the operation of the contactless data carrier of the present embodiment configured as described above will be described.

  Information data and power transmitted from a reader / writer (not shown) are received by a parallel resonant circuit 1 including a coiled antenna 1a and a tuning capacitor 1b, and converted into a DC voltage by a rectifier circuit 2. The rectified voltage passes through the booster circuit 3 to increase the voltage level. The boosted voltage is suppressed to a desired voltage level by the booster circuit regulator 5 and supplied to the analog circuit 11 and the digital circuit regulator 10. . The digital circuit regulator 10 adjusts the power supply voltage for the digital circuit 16 and supplies power to the digital circuit 16. On the other hand, in the communication system circuit B, the clock generation circuit 12 generates a clock from the AC voltage received by the parallel resonance circuit 1, and the demodulation circuit 13 extracts received data by envelope detection and sends it to the digital circuit 16. To do. The modulation circuit 14 AM-modulates the information data from the digital circuit 16, drives the modulation transistor 15 with the modulation signal, switches the load between the terminals of the coiled antenna 1a, and wirelessly transmits the information data to the reader / writer. Send.

  The detailed operation of the booster regulator 5 is as follows. The switching element 8 is always in a conductive state. At this time, the output of the comparator 7 is at the “L” level. The DC voltage rectified by the rectifier circuit 2 and boosted by the booster circuit 3 is accumulated in the smoothing capacitor 4 in the form of electric charge, and is supplied to the analog circuit 11 and the digital circuit regulator 10 in a stable state of voltage smoothing. The voltage dividing resistors 9a and 9b monitor the voltage at this time. The detection voltage by the voltage dividing resistors 9a and 9b is input to the comparator 7 and is compared with the reference voltage generated from the output of the rectifier circuit 2 in the reference voltage generation circuit 6. When the detection voltage is lower than the reference voltage, the output of the comparator 7 remains at the “L” level, and the switching element 8 maintains the conductive state. On the other hand, when the detection voltage becomes equal to or higher than the reference voltage, the output of the comparator 7 is inverted and becomes “H” level, the switching element 8 is turned off, and the output voltage to the analog circuit 11 and the digital circuit regulator 10 increases. Suppress too much. Thus, when the detection voltage drops and the detection voltage falls below the reference voltage, the switching element 8 becomes conductive again. In this way, the DC voltage by the booster circuit 3 and the smoothing capacitor 4 is stably supplied to the analog circuit 11 and the digital circuit regulator 10.

  FIG. 2 shows an output waveform of each circuit in the non-contact data carrier of the present embodiment. As shown in FIG. 2, when information data is wirelessly transmitted from the non-contact data carrier to the reader / writer, the coil antenna 1a is connected in parallel with the modulation data output from the modulation circuit 14 in the communication system circuit B. The modulation transistor 15 is turned on / off, and the load is switched. As a result, the resonant frequency and reception sensitivity of the parallel resonant circuit 1 change, and the output voltage of the rectifier circuit 2 varies at the timing of the modulation data.

  However, the voltage level of the output of the rectifying circuit 2 that is fluctuating is raised by the booster circuit 3 and further suppressed to a desired voltage level by the booster circuit regulator 5, thereby causing the analog circuit 11 and the digital circuit regulator 10 to have a voltage. A stable power supply voltage without fluctuation can be supplied.

(Embodiment 2)
In the second embodiment of the present invention, the booster circuit 3 and the booster regulator 5 are configured to operate only when necessary, thereby reducing power consumption.

  FIG. 3 is a block diagram showing the main configuration of the non-contact data carrier in the second embodiment. In FIG. 3, the same reference numerals as those in FIG. 1 of the first embodiment indicate the same components, and thus detailed description thereof is omitted.

In the present embodiment, a first switching element 21 is inserted between the rectifier circuit 2, the analog circuit 11, and the digital circuit regulator 10. A second switching element 22 is inserted between the rectifier circuit 2, the booster circuit 3, and the booster circuit regulator 5. Further, a third switching element 23 is inserted between the booster circuit regulator 5 and the analog circuit 11 and digital circuit regulator 10. The first switching element 21 is a P-channel MOS transistor, and the second switching element 22 and the third switching element 23 are N-channel MOS transistors. Transmission flag signal S _F from the digital circuit 16 is input to the gate of the second switching element 22, also transmits the flag signal S _F after a predetermined delay time through the delay circuit 24 first switching element 21 and the 3 is input to the gate of the switching element 23. The transmission flag signal S _F, so as to control the on / off of the first to third switching elements 21, 22, 23. Transmission flag signal S _F rises earlier by a predetermined time than the beginning of the modulated data, it is assumed that falls with a delay predetermined time from the end of the modulated data.

  Next, the operation of the contactless data carrier of the present embodiment configured as described above will be described.

FIG. 4 shows an output waveform of each circuit in the contactless data carrier of the present embodiment. Except when wirelessly transmitting information data from the non-contact data carrier to the reader / writer, the transmission flag signal _SF is set to the “L” level, and the first switching element 21 is turned on, so that the rectification of the rectifier circuit 2 The voltage is supplied to the analog circuit 11 and the digital circuit regulator 10 via the first switching element 21. At this time, the second switching element 22 and the third switching element 23 are turned off. Therefore, the booster circuit 3 and the booster circuit regulator 5 are disconnected and in an operation stop state, and power consumption is reduced.

Next, when the transmission flag signal _SF is set to the “H” level, the second switching element 22 is first turned on, the booster circuit 3 starts operating, and the voltage is smoothed by the smoothing capacitor 4. Further, the voltage is stabilized by the booster circuit regulator 5. When the time set by the delay circuit 24 elapses, the delayed transmission flag signal _SF is input to the gates of the first switching element 21 and the third switching element 23. As a result, the first switching element 21 is turned off and the connection with the rectifier circuit 2 is cut off, the third switching element 23 is turned on, and the output voltage of the booster circuit regulator 5 becomes the analog circuit 11 and the digital circuit regulator 10. Will be entered.

  With the above series of operations, the input voltage to the analog circuit 11 and the digital circuit regulator 10 can be kept constant at all times.

  Further, since the booster circuit 3 and the booster circuit regulator 5 are operated only when a power supply fluctuation occurs due to load modulation, the input voltage to the analog circuit 11 and the digital circuit regulator 10 is made constant while suppressing power consumption. Enable.

(Embodiment 3)
In the third embodiment of the present invention, the voltage is monitored on the output side of the booster circuit 3, and the booster circuit 3 is operated only when necessary, thereby suppressing power consumption.

  FIG. 5 is a block diagram showing the main configuration of the non-contact data carrier in the third embodiment. In FIG. 5, the same reference numerals as those in FIG. 1 of the first embodiment indicate the same components.

  In the present embodiment, the booster circuit regulator 5 in FIG. 1 is not used. Instead, the first voltage detection circuit 31 that monitors the output voltage of the booster circuit 3 is connected to the output side of the booster circuit 3, and the operation of the booster circuit 3 is stopped when the output voltage of the booster circuit 3 exceeds a predetermined value. The booster circuit 3 is operated when the value is lower than the predetermined value. In addition, a second voltage detection circuit 32 that monitors the output voltage of the rectifier circuit 2 is connected to the output side of the rectifier circuit 2, and switching is performed between the booster circuit 3, the analog circuit 11, and the digital circuit regulator 10. The element 33 is inserted, and the feedback signal output from the second voltage detection circuit 32 is input to the gate of the switching element 33. The switching element 33 is an N-channel MOS transistor. Other configurations are the same as those in FIG. 1 in the first embodiment, and thus the description thereof is omitted.

  Next, the operation of the contactless data carrier of the present embodiment configured as described above will be described.

  The AC voltage received from the reader / writer is converted into a DC voltage by the rectifier circuit 2 and supplied to the booster circuit 3, the analog circuit 11, and the digital circuit regulator 10. The booster circuit 3 outputs a voltage level higher than the output of the rectifier circuit 2 and accumulates charges in the smoothing capacitor 4 having a large capacity. When charge is sufficiently accumulated in the smoothing capacitor 4 and the output voltage of the booster circuit 3 reaches a predetermined voltage level, the first voltage detection circuit 31 sends a control signal to stop the booster circuit 3. Conversely, when the output voltage of the booster circuit 3 becomes equal to or lower than a predetermined voltage level, the first voltage detection circuit 31 sends a control signal to operate the booster circuit 3. As a result, the output voltage of the booster circuit 3 is maintained at a constant voltage level.

  The output voltage of the rectifier circuit 2 is monitored by the second voltage detection circuit 32. When the output voltage of the rectifier circuit 2 fluctuates due to load modulation and falls below a predetermined voltage level, the second voltage detection circuit The circuit 32 sends an “H” level control signal to the gate of the switching element 33. As a result, the switching element 33 is turned on, and the electric charge accumulated in the smoothing capacitor 4 flows into the output line of the rectifier circuit 2 to raise the voltage level. When the output voltage level of the rectifying circuit 2 exceeds a predetermined voltage level, the second voltage detection circuit 32 sends an “L” level control signal to the gate of the switching element 33. Thereby, the switching element 33 is turned off, and the connection with the output of the booster circuit 3 is disconnected.

  Feedback from the two voltage detection circuits 31 and 32 can reduce fluctuations in the output of the rectifier circuit 2 due to load modulation, and can further reduce power consumption by operating the booster circuit 3 only when necessary. It becomes.

(Embodiment 4)
A non-contact data carrier in Embodiment 4 of the present invention will be described.

  FIG. 6 is a block diagram showing the main configuration of the non-contact data carrier in the fourth embodiment. In FIG. 6, the same reference numerals as those in FIG. 1 of the first embodiment indicate the same components, and detailed description thereof will be omitted.

  In the present embodiment, in addition to the parallel resonant circuit 1, a second parallel resonant circuit 41 including a coiled antenna 41 a that transmits and receives information data to and from a reader / writer and a tuning capacitor 41 b is provided. The first parallel resonant circuit 1 is dedicated to the power supply system circuit A, and the second parallel resonant circuit 41 is dedicated to the communication system circuit B. The modulation transistor 15 is not connected to the first parallel resonant circuit 1. The output terminal of the second parallel resonant circuit 41 is connected to the input terminals of the clock generation circuit 12 and the demodulation circuit 13 in the communication system circuit B. The modulation transistor 15 is connected between both ends of the second parallel resonance circuit 41, and the output terminal of the modulation circuit 14 is connected to the gate of the modulation transistor 15.

  Since the power supply system circuit A can obtain the power of the reader / writer independently of the communication system circuit B by adopting the above-described structure, the power supply circuit A is not affected by the fluctuation of the reception efficiency that occurs at the time of load modulation. Can be obtained.

  The two sets of coiled antennas may be arranged on the same axis in parallel. However, the reception efficiency of the parallel resonant circuit 1 connected to the power circuit A can be greatly affected by the coupling of the inductances of the coiled antennas. There is sex. Therefore, it may be arranged in a plane so that there is no interference between the coiled antennas.

  Of course, the configuration of the present embodiment can be applied to the second embodiment or the third embodiment.

  The technology of the present invention is useful for a highly reliable non-contact data carrier that does not cause malfunction or unstable operation regardless of fluctuations in the rectified voltage caused by load modulation.

The block diagram which shows the main structures of the non-contact data carrier in Embodiment 1 of this invention The figure which shows the output waveform of each circuit in the non-contact data carrier of Embodiment 1 of this invention The block diagram which shows the main structures of the non-contact data carrier in Embodiment 2 of this invention The figure which shows the output waveform of each circuit in the non-contact data carrier of Embodiment 2 of this invention The block diagram which shows the main structures of the non-contact data carrier in Embodiment 3 of this invention The block diagram which shows the main structures of the non-contact data carrier in Embodiment 4 of this invention Block diagram showing the main configuration of a conventional non-contact data carrier

Explanation of symbols

A power supply system circuit B communication system circuit 1 parallel resonance circuit (first parallel resonance circuit)
DESCRIPTION OF SYMBOLS 1a, 41a Coiled antenna 1b, 41b Tuning capacitor 2 Rectifier circuit 3 Boost circuit 4 Smoothing capacitor 5 Regulator for boost circuit 6 Reference voltage generation circuit 7 Comparator 8 Switching element 9a, 9b Voltage dividing resistor 10 Digital circuit regulator 11 Analog circuit 12 Clock generation circuit 13 Demodulation circuit 14 Modulation circuit 15 Transistor for modulation 16 Digital circuit 17 Memory 18 CPU
DESCRIPTION OF SYMBOLS 21 1st switching element 22 2nd switching element 23 3rd switching element 24 Delay circuit 31 1st voltage detection circuit 32 2nd voltage detection circuit 33 Switching element 41 2nd parallel resonant circuit _SF Transmission flag signal

Claims (7)

A parallel resonant circuit consisting of a coiled antenna and a tuning capacitor;
A power supply system circuit that is connected to the parallel resonant circuit and generates a power supply voltage from an AC voltage obtained by the parallel resonant circuit;
A non-contact data carrier connected to the parallel resonant circuit and provided with a communication system circuit that performs clock generation, demodulation and modulation of information data,
The power supply circuit is
A rectifier circuit that converts an AC signal received by the coiled antenna of the parallel resonant circuit into a DC voltage;
A booster circuit for boosting the output voltage of the rectifier circuit;
A regulator for a booster circuit that regulates an output voltage of the booster circuit based on a voltage reference generated from an output of the rectifier circuit;
A non-contact data carrier comprising a digital circuit regulator for regulating the output voltage of the boost regulator for a digital circuit. further,
A first switching element interposed between the output terminal of the rectifier circuit and the input terminal of the digital circuit regulator and analog circuit;
A second switching element interposed between the output terminal of the rectifier circuit and the input terminal of the booster circuit and the regulator for the booster circuit;
The contactless data carrier according to claim 1, wherein both the switching elements are turned on and off by a transmission flag signal output from the digital circuit, and the booster circuit is operated only during modulation. Furthermore, a third switching element is provided between the output terminal of the booster circuit regulator and the input terminal of the digital circuit regulator and the analog circuit,
The contactless data carrier according to claim 2, wherein the third switching element is on / off controlled against the first switching element by the transmission flag signal output from the digital circuit.   4. The contactless data carrier according to claim 3, further comprising a delay circuit that delays a transmission flag signal from the digital circuit for the first switching element and the third switching element. A parallel resonant circuit consisting of a coiled antenna and a tuning capacitor;
A power supply system circuit that is connected to the parallel resonant circuit and generates a power supply voltage from an AC voltage obtained by the parallel resonant circuit;
A non-contact data carrier connected to the parallel resonant circuit and provided with a communication system circuit that performs clock generation, demodulation and modulation of information data,
The power supply circuit is
A rectifier circuit that converts an AC signal received by the coiled antenna of the parallel resonant circuit into a DC voltage;
A digital circuit regulator for regulating the output voltage of the rectifier circuit for a digital circuit;
A booster circuit for boosting the output voltage of the rectifier circuit;
A switching element for cutting off supply of the output voltage of the booster circuit to the regulator for the digital circuit and the analog circuit;
A first voltage detection circuit that detects a voltage level of an output of the booster circuit and stops the operation of the booster circuit when exceeding a predetermined level;
A non-contact including a second voltage detection circuit that detects a voltage level of an output of the rectifier circuit, and conducts the switching element when it is below a predetermined level, and shuts off the switching element when it exceeds a predetermined level Data carrier.   6. The non-contact data carrier according to claim 1, further comprising a smoothing capacitor inserted between the output terminal of the booster circuit and the ground.   The first parallel resonant circuit is used as the first parallel resonant circuit, and a second parallel resonant circuit is provided separately from the first parallel resonant circuit, and the communication system circuit is separated from the first parallel resonant circuit. The contactless data carrier according to claim 1, wherein the contactless data carrier is connected to the second parallel resonant circuit.

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