JP2006019792A - Circuit system of noncontact ic card - Google Patents

Circuit system of noncontact ic card Download PDF

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JP2006019792A
JP2006019792A JP2004192687A JP2004192687A JP2006019792A JP 2006019792 A JP2006019792 A JP 2006019792A JP 2004192687 A JP2004192687 A JP 2004192687A JP 2004192687 A JP2004192687 A JP 2004192687A JP 2006019792 A JP2006019792 A JP 2006019792A
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transponder
reader
resistor
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Makoto Igarashi
良 五十嵐
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

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Abstract

<P>PROBLEM TO BE SOLVED: To provide the circuit system of a noncontact IC card which can improve power feeding efficiency by performing cancellation of a reactance component and impedance matching by a plurality of capacitors in feeding power from a reader to a transponder by electromagnetic coupling, and can efficiently transmit signals to the reader by turning on/off a high-frequency constant current source in the transponder. <P>SOLUTION: Capacitors 3 and 4 perform impedance matching between an internal resistor (resistor 2) of a high-frequency power source 1 and a resistor component (resistor 5) of a primary coil 6 of the reader. The transponder consists of capacitors 11, 12 and 13 for performing impedance matching between a resistor component (resistors 9, 10) of a secondary coil 8 of the transponder and a load (resistor 14). The high-frequency constant current source is coupled to the secondary coil 8 in parallel. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は非接触ICカードシステムにおいて，リーダからトランスポンダに電力を供給して，トランスポンダに内蔵されている集積回路を作動させると共に，トランスポンダからリーダへの信号伝送を行う非接触ICカードの回路方式に関する。 The present invention relates to a contactless IC card circuit system for supplying power from a reader to a transponder to operate an integrated circuit built in the transponder and transmitting signals from the transponder to the reader in a contactless IC card system. .

人と物が移動する場合，これらの個体はトランスポンダを通して固定的に設置された情報処理システム（リーダ）と情報交換を行なう非接触ICカードを用いる改札システムは高い利便性を有する。このシステムは図１に示すように構成され，リーダには高周波電源31，電源内部インピーダンス32，トランス34の1次コイルとキャパシタ33よりなる並列共振回路が含まれ，トランスポンダにはトランス34の2次コイルとキャパシタ35よりなる並列共振回路，２次コイルの高周波電圧を整流するためのダイオード36，ダイオード36に接続される平滑キャパシタ37，及び集積回路38が含まれる。なお，トランス34は１次コイルと２次コイルの関係は固定されておらず，リーダとトランスポンダの位置関係により結合係数が変化する。従って，１次コイルで発生する高周波数磁界が２次コイルを貫通するようにトランスポンダをリーダに近づけることにより結合係数が増大し，リーダからトランスポンダへの供給電力が増大する。なお，従来の回路方式ではリーダおよびトランスポンダにおいてそれぞれの並列共振回路がリーダの送信周波数となるように設計されるので，トランスポンダコイルの高周波電圧は最大となる。しかし，共振回路では電力供給を最大にすることが困難であった。   When people and things move, a ticket gate system using a contactless IC card that exchanges information with an information processing system (reader) that is fixedly installed through a transponder is highly convenient. This system is configured as shown in FIG. 1. The reader includes a high frequency power source 31, a power source internal impedance 32, a parallel resonance circuit including a primary coil of a transformer 34 and a capacitor 33, and the transponder includes a secondary circuit of the transformer 34. A parallel resonance circuit including a coil and a capacitor 35, a diode 36 for rectifying the high-frequency voltage of the secondary coil, a smoothing capacitor 37 connected to the diode 36, and an integrated circuit 38 are included. In the transformer 34, the relationship between the primary coil and the secondary coil is not fixed, and the coupling coefficient changes depending on the positional relationship between the reader and the transponder. Therefore, the coupling coefficient increases by bringing the transponder closer to the reader so that the high frequency magnetic field generated in the primary coil penetrates the secondary coil, and the power supplied from the reader to the transponder increases. In the conventional circuit system, each of the parallel resonant circuits in the reader and transponder is designed to have the transmission frequency of the reader, so that the high frequency voltage of the transponder coil is maximized. However, it has been difficult to maximize power supply with a resonant circuit.

さらに集積回路38への供給電力を大きくするために，図１においてトランス３４の2次コイル，キャパシタ35および37，ダイオード36，集積回路38より構成されるトランスポンダに代わって図２に示す全波整流形のものを用いる。なお，図２において，２次コイルに参照数字39を付してあり，他の部分には図１と同一の参照数字が用いられている。 Further, in order to increase the power supplied to the integrated circuit 38, the full-wave rectification shown in FIG. 2 in place of the transponder comprising the secondary coil of the transformer 34, capacitors 35 and 37, the diode 36 and the integrated circuit 38 in FIG. Use the shape. In FIG. 2, the reference numeral 39 is attached to the secondary coil, and the same reference numerals as in FIG. 1 are used for the other parts.

図１および図２には示されていないが，トランスポンダからリーダへの信号伝送を行なう従来方式は集積回路の電源に並列に抵抗負荷を接続し，この抵抗負荷をオンおよびオフすることにより生ずるリーダの高周波電源31の出力電流変化を検出することにより行なっている。しかし，トランスポンダが消費する電流変化がリーダの出力電流変化に大きく影響しない。これはトランスポンダの電流変化がリーダに効率よく伝送されないためである。すなわち，トランスポンダとリーダを含む回路のインピーダンス整合が不十分であり，さらにコイルのインダクタンスをキャパシタのキャパシタンスで相殺する条件が満足されていないためである。従って，従来の回路方式はインピーダンス整合に基づくものではないので，トランスポンダからリーダへの信号伝送効率を高めることは困難であった。 Although not shown in FIGS. 1 and 2, the conventional system for transmitting signals from the transponder to the reader is connected to a power source of the integrated circuit in parallel with a resistive load, and the reader is generated by turning this resistive load on and off. This is done by detecting a change in the output current of the high frequency power supply 31 of the current. However, the change in current consumed by the transponder does not greatly affect the change in the output current of the reader. This is because the current change of the transponder is not efficiently transmitted to the reader. That is, the impedance matching of the circuit including the transponder and the reader is insufficient, and the condition for canceling the coil inductance with the capacitance of the capacitor is not satisfied. Therefore, since the conventional circuit system is not based on impedance matching, it is difficult to increase the signal transmission efficiency from the transponder to the reader.

この改善策として，インピーダンス整合の原理に基づいて，リーダからトランスポンダへの電力を供給すると共にトランスポンダでは全波整流によって高周波電力を直流電力に変換し，さらに高周波定電流源のオン・オフ制御によりトランスポンダからリーダへ信号を伝送することにより電力供給効率および信号伝送効率を高めることが可能となる。
特開２００３−２２４４１５号公報 As an improvement measure, based on the principle of impedance matching, power is supplied from the reader to the transponder, and the transponder converts high-frequency power into DC power by full-wave rectification, and further controls the transponder by on / off control of the high-frequency constant current source. It is possible to increase the power supply efficiency and the signal transmission efficiency by transmitting a signal from the reader to the reader.
JP 2003-224415 A

リーダとトランスポンダのそれぞれに高周波電源の周波数で共振する並列共振回路を用いる従来方式では，インピーダンス整合の配慮がなされないので電力供給効率の最大化は困難である。また，トランスポンダからリーダへの信号伝送を行なう場合においても，単に負荷を変化させるだけでは信号伝送効率を高めることができない。従って，電力供給効率および信号伝送効率を高めることが課題である。 In the conventional method using a parallel resonant circuit that resonates at the frequency of the high-frequency power source for each of the reader and the transponder, it is difficult to maximize the power supply efficiency because impedance matching is not taken into consideration. Even when signal transmission from the transponder to the reader is performed, the signal transmission efficiency cannot be increased simply by changing the load. Therefore, it is a problem to improve power supply efficiency and signal transmission efficiency.

上記目的を達成するために，本発明の非接触ICカードの回路方式は，高周波電源の内部抵抗とリーダの１次コイルの抵抗とが整合するように２個のキャパシタを使用する。その内の１個は高周波電源と１次コイルと間に接続され，他は上記１次コイルと並列に接続される。キャパシタの数を３個使用することもできる。同様にトランスポンダにおいても，負荷抵抗と２次コイルの抵抗成分とが整合するように複数個（３個が望ましい）のキャパシタを使用する。もちろん，キャパシタを２個にすることもできる。 In order to achieve the above object, the circuit system of the contactless IC card of the present invention uses two capacitors so that the internal resistance of the high frequency power supply matches the resistance of the primary coil of the reader. One of them is connected between the high-frequency power source and the primary coil, and the other is connected in parallel with the primary coil. Three capacitors can also be used. Similarly, in the transponder, a plurality of capacitors (preferably three) are used so that the load resistance matches the resistance component of the secondary coil. Of course, two capacitors can be used.

リーダにおいては，上記複数個のキャパシタは１次コイルのインダクタンスによるリアクタンス分を相殺することにより無効電力の影響を排除して，電力供給効率を高める働きを有する。同様に，トランスポンダにおいても，上記複数個のキャパシタは２次コイルのインダクタンスによるリアクタンス分を相殺することにより無効電力の影響を排除して，電力供給効率を高める働きを有する。 In the reader, the plurality of capacitors have a function of improving the power supply efficiency by canceling out the reactance due to the inductance of the primary coil to eliminate the influence of reactive power. Similarly, in the transponder, the plurality of capacitors have a function of increasing the power supply efficiency by canceling the reactance due to the inductance of the secondary coil to eliminate the influence of reactive power.

トランスポンダからリーダへの信号伝送効率を高めるためには２次コイルに信号電流を直接供給することが大切である。この場合，すでにインピーダンス整合が行なわれているので，信号電流は効率よくリーダに供給される。出力インピーダンスの高い定電流源を用いて信号電流を供給すると，インピーダンス整合状態に影響を及ぼすことがないので，高い信号伝送効率が得られる。 In order to increase the signal transmission efficiency from the transponder to the reader, it is important to supply the signal current directly to the secondary coil. In this case, since impedance matching has already been performed, the signal current is efficiently supplied to the reader. When a signal current is supplied using a constant current source having a high output impedance, the impedance matching state is not affected, so that high signal transmission efficiency can be obtained.

上記のように構成された非接触ICカードの回路方式において，トランスの1次コイルおよび２次コイルのリアクタンスを複数個のキャパシタで相殺して無効電力の影響を排除すると共に高周波電源の内部インピーダンスと1次コイルの抵抗成分とのインピーダンス整合を行なうことにより，リーダにおける電力供給効率を高める。この原理をトランスポンダの回路方式に取り入れることにより２次コイルの抵抗成分と負荷抵抗とのインピーダンス整合を行ない，同時に無効電力の影響を排除することにより負荷への電力供給効率を高める。 In the circuit system of the non-contact IC card configured as described above, the reactance of the primary coil and secondary coil of the transformer is canceled by a plurality of capacitors to eliminate the influence of reactive power and the internal impedance of the high frequency power supply. Improves power supply efficiency in the reader by matching impedance with the resistance component of the primary coil. By incorporating this principle in the circuit system of the transponder, impedance matching between the resistance component of the secondary coil and the load resistance is performed, and at the same time, the power supply efficiency to the load is enhanced by eliminating the influence of reactive power.

さらにトランスポンダからリーダへ信号伝送は，２次コイルに接続された高周波定電流源のオンおよびオフにより行なうことにより信号は効率よくリーダに伝送される。このことは集積回路が必要とする電力を少ない損失で供給できるため消費電力の低減に伴う動作の安定化，小型化，信頼性向上等の利点が生ずる。 Furthermore, signal transmission from the transponder to the reader is performed by turning on and off the high-frequency constant current source connected to the secondary coil, whereby the signal is efficiently transmitted to the reader. This is because the power required by the integrated circuit can be supplied with little loss, and there are advantages such as stabilization of operation, reduction in size, and improvement of reliability accompanying reduction in power consumption.

リーダにおいては，高周波電源の内部インピーダンスは一次コイルの抵抗成分より高く，トランスポンダにおいては，負荷抵抗（全波整流回路の入力抵抗を意味する）は２次コイルの抵抗成分より高いので，リーダのインピーダンス整合は高周波電源に直列にキャパシタを接続すると共に別のキャパシタを１次コイルと並列に接続し，トランスポンダのインピーダンス整合は２次コイルに並列にキャパシタを接続すると共に別のキャパシタを負荷抵抗に直列に接続し，２次コイルの両端に高周波定電流源を接続して実現した。 In the reader, the internal impedance of the high frequency power supply is higher than the resistance component of the primary coil, and in the transponder, the load resistance (meaning the input resistance of the full-wave rectifier circuit) is higher than the resistance component of the secondary coil. For matching, a capacitor is connected in series to the high frequency power supply and another capacitor is connected in parallel with the primary coil. Impedance matching of the transponder is connected in parallel to the secondary coil and another capacitor is connected in series to the load resistor. This was realized by connecting a high-frequency constant current source to both ends of the secondary coil.

実施例について図面を参照して説明する。図３は本発明による非接触ICカードの回路方式について，インピーダンス整合の観点から動作原理を説明するための等価回路図であり，リーダとトランスポンダが含まれる。さらに，リーダは高周波電源１，高周波電源１の内部抵抗２，インピーダンス整合のためのキャパシタ３および４，１次コイル６，およびコイル６の抵抗成分に対応する抵抗５よりなる。トランスポンダは２次コイル８，２次コイル８の抵抗成分に対応する抵抗９および１０，インピーダンス整合のためのキャパシタ１１，１２および１３，および負荷抵抗１４よりなる。従って，トランスポンダは平衡形四端子網を構成しており，後述のように全波整流を可能とするものである。 Embodiments will be described with reference to the drawings. FIG. 3 is an equivalent circuit diagram for explaining the principle of operation of the circuit system of the contactless IC card according to the present invention from the viewpoint of impedance matching, and includes a reader and a transponder. Further, the reader includes a high frequency power source 1, an internal resistance 2 of the high frequency power source 1, a capacitor 3 for impedance matching, a primary coil 6, and a resistor 5 corresponding to a resistance component of the coil 6. The transponder includes a secondary coil 8, resistors 9 and 10 corresponding to resistance components of the secondary coil 8, capacitors 11, 12 and 13 for impedance matching, and a load resistor 14. Accordingly, the transponder constitutes a balanced four-terminal network and enables full-wave rectification as will be described later.

まず，トランス７の結合係数について述べると，結合係数はリーダとトランスポンダとの位置関係によって変化するが，トランス７の結合係数を設計上の最小値において，高周波電源からの電力供給効率を最大にしておけば，上記結合係数が大きい場合にはより大きな電力を供給できる。このことから結合係数が設計上の最小値において電力供給効率を最大にすることが重要となる。結合係数が小さい場合には，リーダとトランスポンダのそれぞれを独立した回路で近似できる。すなわち，リーダにおいては，１次コイル６，キャパシタ３および４，抵抗２および５，高周波電源１のみで構成する。この回路の電力供給効率を最大にする条件は，１次コイル６のリアクタンスとキャパシタ３および４のリアクタンスを相殺する条件は（数１）で与えられる。さらに高周波電源の内部インピーダンス（抵抗２）とコイル６の抵抗成分（抵抗５）とのインピーダンス整合を行なう条件は（数２）および（数３）で与えられる。 First, the coupling coefficient of the transformer 7 will be described. The coupling coefficient changes depending on the positional relationship between the reader and the transponder. The coupling coefficient of the transformer 7 is set to the minimum design value, and the power supply efficiency from the high frequency power supply is maximized. In this case, when the coupling coefficient is large, larger power can be supplied. Therefore, it is important to maximize the power supply efficiency when the coupling coefficient is the minimum value in the design. When the coupling coefficient is small, the reader and the transponder can be approximated by independent circuits. That is, the reader is composed of only the primary coil 6, the capacitor 3 and 4, the resistor 2 and 5, and the high-frequency power source 1. The condition for maximizing the power supply efficiency of this circuit is given by (Equation 1) that cancels the reactance of the primary coil 6 and the reactance of the capacitors 3 and 4. Further, the conditions for impedance matching between the internal impedance (resistor 2) of the high frequency power supply and the resistance component (resistor 5) of the coil 6 are given by (Equation 2) and (Equation 3).

Figure 2006019792
Figure 2006019792

Figure 2006019792
Figure 2006019792

Figure 2006019792
Figure 2006019792

上式において，Ｌ１，ＣＡ，ＣＢ，Ｒ０，Ｒ１およびωはそれぞれコイル６のインダクタンス，キャパシタ３のキャパシタンス，キャパシタ４のキャパシタンス，抵抗２の抵抗値，抵抗５の抵抗値，および角周波数を表す。 In the above equation, L 1 , C A , C B , R 0 , R 1 and ω are the inductance of the coil 6, the capacitance of the capacitor 3, the capacitance of the capacitor 4, the resistance value of the resistor 2, the resistance value of the resistor 5, and Represents angular frequency.

次にトランスポンダの近似回路は２次コイル８，コイル８の抵抗成分（抵抗９および１０），キャパシタ１１，キャパシタ１２および１３，および負荷抵抗（抵抗１４）より構成される。図には明記されていないが，トランスポンダへの電力供給は1次コイルを流れる高周波電流と相互インダクタンスにより行なう。リーダの場合と同様にトランスポンダの負荷（抵抗１４）に供給される電力を最大に条件は次のようになる。 The approximate circuit of the transponder is composed of the secondary coil 8, the resistance component of the coil 8 (resistors 9 and 10), the capacitor 11, the capacitors 12 and 13, and the load resistor (resistor 14). Although not clearly shown in the figure, power is supplied to the transponder by high-frequency current flowing through the primary coil and mutual inductance. As in the case of the reader, the conditions for maximizing the power supplied to the load (resistor 14) of the transponder are as follows.

Figure 2006019792
Figure 2006019792

Figure 2006019792
Figure 2006019792

Figure 2006019792
Figure 2006019792

上式において，Ｌ２，Ｃ2，Ｃ３，ＲＬ，Ｒ２およびωはそれぞれ２次コイル８の自己インダクタンス，キャパシタ１１のキャパシタンス，キャパシタ１２および１３のキャパシタンス，負荷（抵抗１４）の抵抗値，コイル８の抵抗成分を二分した抵抗９および１０の抵抗値，および角周波数を表す。 In the above equation, L 2 , C 2 , C 3 , R L , R 2 and ω are the self-inductance of the secondary coil 8, the capacitance of the capacitor 11, the capacitance of the capacitors 12 and 13, and the resistance value of the load (resistor 14), respectively. , The resistance values of the resistors 9 and 10 obtained by dividing the resistance component of the coil 8 into two, and the angular frequency.

これまで述べたように高周波電源１の内部抵抗を示す抵抗２と１次コイル６の抵抗成分を示す抵抗５とのインピーダンス整合を行なうと共に２次コイル８の抵抗成分を示す抵抗９および１０と負荷抵抗１４とのインピーダンス整合が行なわれる。さらに１次コイル６の自己インダクタンスによるリアクタンスをキャパシタ３および４のリアクタンスで相殺することにより，高周波電源からの電力供給効率を高める。この原理をトランスポンダ回路にも適用して負荷抵抗１４への電力供給効率を高める。 As described above, impedance matching is performed between the resistor 2 indicating the internal resistance of the high-frequency power source 1 and the resistor 5 indicating the resistance component of the primary coil 6 and the resistors 9 and 10 indicating the resistance component of the secondary coil 8 and the load. Impedance matching with the resistor 14 is performed. Further, the reactance due to the self-inductance of the primary coil 6 is canceled by the reactance of the capacitors 3 and 4, thereby increasing the power supply efficiency from the high-frequency power source. This principle is also applied to the transponder circuit to increase the power supply efficiency to the load resistor 14.

次に図４を参照して高周波電圧を全波整流するための回路について説明すると，コイル８に電磁誘導される高周波電圧はキャパシタ１２および１３を通して全波整流回路に与えられる。全波整流回路はダイオード４０，４１，４２，４３と平滑キャパシタ３７より構成される。ダイオード４０，４２の共通カソードから正の直流電圧が，ダイオード４１，４３の共通アノードから負の直流電圧が現れ，集積回路３８に電力を供給する。主として集積回路で消費される電力に等価となるように抵抗１４の抵抗値が選ばれる。図４は回路素子の接続を示すもので，２次コイル８の抵抗成分は示されていないが，図３のトランスポンダ等価回路と矛盾することはない。 Next, a circuit for full-wave rectification of a high-frequency voltage will be described with reference to FIG. 4. A high-frequency voltage electromagnetically induced in the coil 8 is applied to the full-wave rectification circuit through capacitors 12 and 13. The full-wave rectifier circuit includes diodes 40, 41, 42, 43 and a smoothing capacitor 37. A positive DC voltage appears from the common cathode of the diodes 40 and 42, and a negative DC voltage appears from the common anode of the diodes 41 and 43 to supply power to the integrated circuit 38. The resistance value of the resistor 14 is selected so as to be equivalent to the power consumed mainly in the integrated circuit. FIG. 4 shows the connection of the circuit elements, and the resistance component of the secondary coil 8 is not shown, but is not inconsistent with the transponder equivalent circuit of FIG.

以上を要約すると，リーダのアンテナコイルに発生する高周波電磁界がトランスポンダコイルを突き抜けることにより、トランスポンダに電力を供給する非接触ICカードシステムにおいて、トランスポンダコイルに発生する高周波電圧がインピーダンス変換用キャパシタを通して全波整流回路に印加されるように構成した非接触ICカードの回路方式は電力供給効率を高める上で有用であることが分かる。 In summary, in a contactless IC card system that supplies power to the transponder by the high-frequency electromagnetic field generated in the antenna coil of the reader penetrating the transponder coil, the high-frequency voltage generated in the transponder coil passes through the impedance conversion capacitor. It can be seen that the circuit system of the non-contact IC card configured to be applied to the wave rectifier circuit is useful for increasing the power supply efficiency.

次に図５（図４に直流電源印加端子１４，高周波電流源１５および１６を付加したもの）を参照して，トランスポンダからリーダへ信号伝送について述べると，２次コイルに外部から高周波電流を供給するために２個の高周波電流源１５および１６を２次コイル８に接続すると，接続点におけるインピーダンスは低いので，高周波電流源１５および１６からの高周波電流は容易に２次コイル８を流れる。また，高周波電流源１５および１６の内部インピーダンスは非常に高いので，高周波電流源１５および１６の接続によって整合条件は変わることがない。このことはトランスポンダからリーダへの信号伝送効率は高周波電流源１５および１６の接続によって影響されることがないので，高くできることを意味する。なお，２次コイルに接続された高周波電流源のオンおよびオフを２値情報に対応させることによりリーダにおける信号受信が可能である。さらに，高周波電流源の位相がリーダの高周波電源の位相より約４５度進んでいるときに信号伝送効率が最大となることが判明した。なお，図５には2個の高周波電流源が使用されているが，1個のOTA(Operational Transconductance Amplifier)を使用した高周波電流源をトランスポンダコイル８に並列に接続してもよい。以上の説明で明らかなようにトランスポンダコイルとインピーダンス変換用キャパシタの接続点に高周波電流源を接続して，リーダへの信号伝送を行なう非接触ICカードの回路方式の有用性が確かめられている。 Next, referring to FIG. 5 (with DC power supply terminal 14 and high-frequency current sources 15 and 16 added to FIG. 4), signal transmission from the transponder to the reader will be described. High-frequency current is supplied to the secondary coil from the outside. Therefore, when the two high-frequency current sources 15 and 16 are connected to the secondary coil 8, the impedance at the connection point is low, so that the high-frequency current from the high-frequency current sources 15 and 16 easily flows through the secondary coil 8. Further, since the internal impedance of the high-frequency current sources 15 and 16 is very high, the matching condition does not change depending on the connection of the high-frequency current sources 15 and 16. This means that the signal transmission efficiency from the transponder to the reader is not affected by the connection of the high-frequency current sources 15 and 16, and can be increased. The reader can receive a signal by making the high-frequency current source connected to the secondary coil on and off corresponding to binary information. Further, it has been found that the signal transmission efficiency is maximized when the phase of the high-frequency current source is about 45 degrees ahead of the phase of the high-frequency power source of the reader. Although two high-frequency current sources are used in FIG. 5, a high-frequency current source using one OTA (Operational Transconductance Amplifier) may be connected to the transponder coil 8 in parallel. As is apparent from the above description, the usefulness of the circuit system of the non-contact IC card that transmits a signal to the reader by connecting a high-frequency current source to the connection point between the transponder coil and the capacitor for impedance conversion has been confirmed.

以上述べたように本発明によれば，複数個のキャパシタのリアクタンスとコイルのリアクタンスとを相殺させると共にインピーダンス整合を行ない，あらに全波整流回路を平衡形四端子網で構成することにより集積回路３８への供給電圧を１ボルトから３ボルトに高めることができた。 As described above, according to the present invention, the reactance of a plurality of capacitors and the reactance of a coil are canceled and impedance matching is performed, and a full-wave rectifier circuit is further constituted by a balanced four-terminal network. The supply voltage to 38 could be increased from 1 to 3 volts.

次にトランスポンダからリーダへの信号伝送特性について述べると，従来の方法（負荷を変化させる方法）と本発明による高周波電流源を用いる方法についての信号伝送特性をそれぞれ表１および表２に示す。表１は図３において負荷抵抗１４を変化させて抵抗２および負荷抵抗１４を流れる高周波電流の振幅を調べたものであり，表２は高周波電流源（振幅2mA）をキャパシタ１１に並列に挿入した場合である。図３の他の素子の値は高周波電源１（振幅=８ボルト，周波数=13.56MHz），抵抗２=50Ω，キャパシ３=33pF，キャパシ４=105pF，抵抗5=2.8Ω，コイル６の自己インダクタンス=1uH，コイル8の自己インダクタンス=2uH，抵抗9，10=1.7Ω，キャパシタ11=60pF，キャパシタ12，13=19pFである。 Next, the signal transmission characteristics from the transponder to the reader will be described. Table 1 and Table 2 show the signal transmission characteristics of the conventional method (method of changing the load) and the method using the high-frequency current source according to the present invention, respectively. Table 1 shows the amplitude of the high-frequency current flowing through the resistor 2 and the load resistor 14 by changing the load resistor 14 in FIG. 3, and Table 2 shows that a high-frequency current source (amplitude 2 mA) is inserted in parallel with the capacitor 11. Is the case. The values of the other elements in FIG. 3 are the high frequency power source 1 (amplitude = 8 volts, frequency = 13.56 MHz), resistance 2 = 50Ω, capacity 3 = 33 pF, capacity 4 = 105 pF, resistance 5 = 2.8Ω, self-inductance of the coil 6 = 1 uH, self-inductance of coil 8 = 2 uH, resistance 9, 10 = 1.7Ω, capacitor 11 = 60 pF, capacitor 12, 13 = 19 pF.

Figure 2006019792
Figure 2006019792

Figure 2006019792
Figure 2006019792

表１において，負荷抵抗１４を180Ωから120Ωに変化させると負荷抵抗１４を流れる電流1.9mA増加する。このときリーダの抵抗２を流れる電流は0.8mA減少することが分かる。一方，表2から高周波電流源をオン，オフした場合において，抵抗１４を流れる電流変化は，その位相が高周波電源に対して45度進んでいるときに最大となり，その値は3.9mAに達する。このことからトランスポンダにおいて，2mA程度の電流変化を与えた場合，リーダにおける電流変化は従来の方法に比して本発明の方法は４倍程度大きくなることが分かる。従って，信号伝送特性が改善できれば，コイルのインダクタンス特に相互インダクタンスを小さくすることができるので，コイル寸法の小型化および消費電力の低減が可能となり，回路の安定動作，小型化，信頼性向上等の利点が得られる。 In Table 1, when the load resistance 14 is changed from 180Ω to 120Ω, the current flowing through the load resistance 14 increases by 1.9 mA. At this time, it can be seen that the current flowing through the resistor 2 of the reader is reduced by 0.8 mA. On the other hand, when the high-frequency current source is turned on and off from Table 2, the current change flowing through the resistor 14 becomes maximum when the phase advances 45 degrees with respect to the high-frequency power source, and the value reaches 3.9 mA. From this, it can be seen that when a current change of about 2 mA is applied to the transponder, the current change in the reader is about four times as large as that of the conventional method. Therefore, if the signal transmission characteristics can be improved, the inductance of the coil, especially the mutual inductance, can be reduced, so that the coil size can be reduced and the power consumption can be reduced, and the circuit can be operated stably, downsized, improved in reliability, etc. Benefits are gained.

従来の非接触ICカードの回路方式Conventional contactless IC card circuit system 従来のトランスポンダ部の回路方式Conventional transponder circuit system 本発明の一実施例に等価回路An equivalent circuit in one embodiment of the present invention 本発明の一実施例による全波整流回路Full-wave rectifier circuit according to one embodiment of the present invention 本発明の一実施例による高周波電流源のオン，オフによる信号伝送回路方式Signal transmission circuit system by turning on / off high frequency current source according to one embodiment of the present invention

符号の説明Explanation of symbols

１は高周波電源
２は内部抵抗
３はキャパシタ
４はキャパシタ
５は抵抗
６は１次コイル
７はトランス
８は２次コイル
９，１０は抵抗
11,12,13はキャパシタ
14は負荷抵抗
15は直流電圧印加端子
16,17は高周波電流源
31は高周波電源
32は抵抗
33はキャパシタ
35はキャパシタ
36はダイオード
37はキャパシタ
38は集積回路
40,41,42,43はダイオード

1 is a high frequency power source 2 is an internal resistor 3 is a capacitor 4 is a capacitor 5 is a resistor 6 is a primary coil 7 is a transformer 8 is a secondary coil 9 and 10 is a resistor
11,12,13 are capacitors
14 is load resistance
15 is a DC voltage application terminal
16 and 17 are high-frequency current sources
31 is a high frequency power supply
32 is resistance
33 is a capacitor
35 is a capacitor
36 is a diode
37 is a capacitor
38 is an integrated circuit
40, 41, 42, 43 are diodes

Claims (2)

リーダのアンテナコイルに発生する高周波電磁界がトランスポンダコイルを突き抜けることにより、トランスポンダに電力を供給する非接触ICカードシステムにおいて、トランスポンダコイルに発生する高周波電圧がインピーダンス変換用キャパシタを通して全波整流回路に印加されるように構成した非接触ICカードの回路方式。 In a contactless IC card system that supplies power to the transponder when the high-frequency electromagnetic field generated in the antenna coil of the reader penetrates the transponder coil, the high-frequency voltage generated in the transponder coil is applied to the full-wave rectifier circuit through the impedance conversion capacitor. Non-contact IC card circuit system configured to be used. 請求項１記載の非接触ICカードの回路方式において、トランスポンダコイルとインピーダンス変換用キャパシタの接続点に高周波定電流源を接続して，リーダへの信号伝送を行なう非接触ICカードの回路方式。
2. The non-contact IC card circuit system according to claim 1, wherein a high-frequency constant current source is connected to a connection point between the transponder coil and the impedance conversion capacitor to perform signal transmission to a reader.
JP2004192687A 2004-06-30 2004-06-30 Circuit system of noncontact ic card Pending JP2006019792A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008131115A (en) * 2006-11-17 2008-06-05 Tamura Seisakusho Co Ltd Antenna coil and communication apparatus
CN114499302A (en) * 2021-12-29 2022-05-13 江苏东晔电气设备有限公司 Method and system for intelligently matching transformers

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008131115A (en) * 2006-11-17 2008-06-05 Tamura Seisakusho Co Ltd Antenna coil and communication apparatus
CN114499302A (en) * 2021-12-29 2022-05-13 江苏东晔电气设备有限公司 Method and system for intelligently matching transformers
CN114499302B (en) * 2021-12-29 2023-07-04 江苏东晔电气设备有限公司 Method and system for intelligently matching transformers

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