JP2003319574A - Semiconductor integrated circuit device and non-contact electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control the voltage, generated in the antenna terminal of a non- contact IC card, prevented from exceeding the breakdown voltage of an element. <P>SOLUTION: A first rectifier transistor connecting a gate and a drain through a first resistor means to make a rectified current flow between first/second input terminals, a first voltage control current source formed with a current responding to the control voltage, a first voltage detection means formed with the control voltage so as to make rectified voltage obtained in a source side of the first rectifier transistor agree with the prescribed reference voltage, and a first one-way directional element allowing a current corresponding to the rectified current to flow between the first input terminal and a first output terminal out-putting the rectified voltage, are provided, the resistance of the first resistor means is set so as to prevent the voltage generated between the first/second input terminals from exceeding the breakdown voltage of an element constituting the circuit. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor integrated circuit device and a non-contact type electronic device. The technique is mainly effective for use in a stable power supply circuit of a non-contact type IC card and a semiconductor integrated circuit device mounted therein.

[0002]

2. Description of the Related Art The documents referred to in this specification are as follows, and the documents are referred to by their document numbers.

[Reference 1]: Japanese Patent Application Laid-Open No. 2001-250097
Publication [Reference 2]: Japanese Patent Application Laid-Open No. 10-210751 [Reference 3]: Japanese Patent Application Laid-Open No. 2001-274339 The above [Reference 1] describes transmission of data from a non-contact type IC card to a reader / writer. Described below is one in which the load of the contact type IC card is changed and the change of the load is detected by the reader / writer. Further, FIG. 2 of the document 1 shows a non-contact type IC card provided with a limiter circuit for protection against breakdown voltage and a dynamic impedance variation function due to intermittent load as communication means to the reader / writer. ing.

FIG. 7 described in [Reference 2] describes an example of a voltage limiter circuit applied to a power supply circuit of a non-contact type IC card.

[0005]

In recent years, so-called IC cards equipped with semiconductor integrated circuit devices have become widespread. The IC card exchanges information between the reader / writer and the semiconductor integrated circuit device, and realizes various functions equivalent to those currently performed by the magnetic card. The so-called non-contact type IC card exchanges information between the reader / writer device and the semiconductor integrated circuit device, transmits the data held by the non-contact type IC card, and transmits the data transmitted from the reader / writer. Realizes various functions such as holding.

Further, in a non-contact type IC card which does not have electrodes for supplying signals or voltage to the outside, electromagnetic waves supplied from a reader / writer are received by an antenna mounted on the IC card and generated at both ends of the antenna. The generated voltage is rectified and smoothed to form an internal voltage required for the operation of the semiconductor integrated circuit device mounted therein. In this case, if excessive power is supplied from the reader / writer and a power supply voltage higher than the withstand voltage of the elements forming the internal circuit is supplied, the elements will be destroyed. In order to prevent this, many devices are equipped with a power supply voltage regulator circuit that monitors the internally generated power supply voltage level and controls so as not to supply a power supply voltage higher than the breakdown voltage of the element.

Prior to the present application, the inventors of the present application [Reference 1]
The following studies were conducted on a device in which the load of the non-contact type IC card is varied and the variation of the load is detected by the reader / writer.

FIG. 1 shows a non-contact type IC card when the limiter circuit and the transmission circuit of [Reference 1] studied by the inventors of the present application are applied to a semiconductor integrated circuit device mounted on the non-contact type IC card. An example of operation waveforms at the time of data transmission from the device to the reader / writer is shown. In the ILSW of FIG. 1, the current I flowing in the transmission circuit composed of 9 and 11 or 10 and 12 shown in FIG.
The LIM has a current flowing through the limiter circuit shown in FIG. 2 described in [Reference 1], and the ISUM has the above currents ILSW and IL.
The respective IM sums are shown.

When data is transmitted from the non-contact type IC card to the reader / writer, FETs 9 and 10 as switch elements shown in FIG. 2 of [Document 1] are turned on,
A current flows from the antenna terminal through the resistor 11 and the FET 9 or from the antenna terminal through the resistor 12 and the FET 10 to the ground terminal. Further, Pon in FIG. 1 indicates a period in which the transmission circuit is turned on and current is flowing through the transmission circuit, and Poff indicates a period in which the transmission circuit is turned off and current is not flowing through the transmission circuit.

When current is flowing through the limiter during the period Poff and the transmitter circuit is turned on during the period Pon and current flows through the transmitter circuit, the potential of the antenna terminal drops and the power supply voltage tends to drop. The current ILIM flowing through the limiter circuit is reduced. As a result, the current ILSW that flows in the transmission circuit and the current I that flows in the limiter circuit
The LIMs cancel out and the sum of these, ISUM, disappears. Therefore, since there is no change in the current flowing through the antenna terminal, that is, there is no change in the current of the entire non-contact type IC card, it becomes difficult for the reader / writer to receive the data transmitted by the non-contact type IC card. noticed.

An object of the present invention is to provide a method for realizing stable transmission from a non-contact type IC card to a reader / writer.

[0012]

The outline of the typical inventions among the inventions disclosed in the present application will be briefly described as follows. That is, the first AC voltage is applied
An input terminal and a second input terminal are provided, the drain (or collector) is connected to the second input terminal, and the gate (or base) and the drain (or collector) are connected via a first resistance means. 1 input terminal and above second
A first rectifying transistor for flowing a rectifying current between the input terminal, a first voltage controlled current source for forming a current in response to a control voltage and supplying the current to the first resistance means, and a source for the first rectifying transistor ( Or between the first input terminal and the first output terminal that outputs the rectified voltage, and the first voltage detection means that forms the control voltage so that the rectified voltage obtained on the (emitter) side matches a predetermined reference voltage. A first unidirectional element for flowing a current corresponding to the rectified current, wherein the source (or emitter) of the first rectification transistor is connected to a second output terminal for outputting a rectified voltage, Two
The resistance value of the first resistance means is set so that the voltage generated between the input terminals does not exceed the withstand voltage of the elements constituting the circuit.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a semiconductor integrated circuit device and an IC card according to the present invention will be described below.
Description will be given with reference to the accompanying drawings. The circuit element forming each block of the embodiment is not particularly limited, but a known C element is used.
It is formed on one semiconductor substrate such as single crystal silicon by semiconductor integrated circuit technology such as MOS (complementary MOS transistor) or bipolar transistor.

FIG. 2 is a block diagram showing one embodiment of a semiconductor integrated circuit device having a power supply circuit and a transmission circuit according to the present invention and a non-contact type IC card equipped with the semiconductor integrated circuit device. The signal and power output from the reader / writer RW through the antenna LRW in the form of electromagnetic waves are received by the antenna LCA incorporated in the IC card CA.
A means RECT for generating a voltage from the power received by the antenna LCA, a means MC for processing the received signal and storing data, a detection of the signal received by the antenna LCA, and a signal from the IC card to the reader / writer. It is composed of communication means TR for transmitting.

FIG. 3 shows the current-voltage characteristic VL generated at both ends of the antenna terminal provided in the non-contact type IC card by the electric power supplied in the form of electromagnetic waves from the reader / writer. This means that the voltage across the antenna changes depending on the current flowing through the load connected to the antenna, and is equivalent to a voltage source having an output impedance. At this time, the slope of the current-voltage characteristic VL becomes the output impedance.

FIG. 4 shows an equivalent circuit of a power supply circuit and a transmission circuit mounted on the semiconductor integrated circuit device according to the present invention and an antenna mounted on a reader / writer and a non-contact type IC card. The circuit is shown. Non-contact type I
Terminal L for connecting the antenna mounted on the C card
An NMOS transistor M01, a diode D02, a resistor R01, and a voltage detection circuit G01 are provided between A and LB.
And the voltage-controlled current source G02 constitute the power supply circuit shown in FIG. 1 described in [Document 3], and the diode D01
The current source I01 and the switch S01 constitute a transmission circuit. The on / off of S01 which constitutes the transmission circuit is controlled to generate a current change I01 and transmit the data to the reader / writer.

Further, in FIG. 4, the antenna provided in the reader / writer and the non-contact type IC card is shown by the equivalent circuit described in FIG. 3, and the AC voltage source V0
1 and a resistor ROUT that represents the output impedance. Here, the change in the current flowing through the resistor ROUT becomes equivalent to the data transmitted to the reader / writer.

In FIG. 4, the resistance RO when the switch S01 is turned on and when the switch S01 is turned off.
The change IDLT in the current flowing through the UT is as shown in Equation 1.

[0019]

## EQU00001 ## IDLT = I01.times.R01 / (R01 + ROUT) (1) In the above Equation 1, the current change I01 due to the transmission circuit is attenuated by the resistor R01 and the resistor ROUT forming the power supply circuit, and the non-contact type IC card. It shows that it becomes the whole current change.

From this, the resistance R01 is the resistance RO
If it is made sufficiently larger than UT, there is an advantage that the attenuation rate of the current change I01 becomes small, but conversely the resistance R
It is shown that when 01 is much smaller than the resistance ROUT, the attenuation rate of the current change I01 increases. In particular, if the resistance R01 is 0Ω, the resistance R
The current change I01 is multiplied by 0 regardless of OUT, and the current change I01 is canceled by the power supply circuit, indicating that data is not transmitted to the reader / writer. This represents a phenomenon in which the current flowing in the transmitting circuit and the current flowing in the limiter circuit shown in [Document 1] are canceled.

FIG. 5 is a basic circuit configuration diagram of another embodiment of the power supply circuit and the transmission circuit mounted on the semiconductor integrated circuit device according to the present invention, and the reader / writer and the non-contact type IC.
An equivalent circuit of the antenna mounted on the card is shown. In this embodiment, a modification of the above-mentioned transmission circuit of FIG. 4 is shown.

In this embodiment, the transmission circuit composed of the switch S02 and the current source I02 is connected to the output terminal OUT.
1 connected to the output terminal OUT2, the NMOS transistor M01 also functions as the diode D01 of FIG. 4 described above. Also in this embodiment, FIG.
Similarly to the above, the change in the current flowing through the resistor R01 becomes the number 1, and the function equivalent to that in FIG. 4 can be realized.

On the other hand, as shown in [Document 3], it is possible to protect the power supply circuit so as not to exceed the withstand voltage of the elements constituting the circuit connected between the output terminals OUT1 and OUT2. , [Reference 3], it is difficult to protect the withstand voltage of the power supply circuit. Therefore, it is necessary to mount an overvoltage protection circuit for protecting the withstand voltage of the power supply circuit or the like, that is, for preventing the voltage generated at the antenna terminal from exceeding the withstand voltage of the elements forming the regulator circuit or the rectifier circuit.

Since the overvoltage protection circuit required here is for the purpose of limiting the voltage generated at the antenna terminal, a circuit configuration that consumes power by flowing a current as in [Reference 2] is suitable. There is. As a result, as in [Reference 1], the current change in the transmission circuit is offset by the current change in the overvoltage protection circuit, the load change of the entire non-contact type IC card is reduced, and the reader / writer becomes a non-contact type. There is a possibility that the data transmitted by the IC card cannot be detected.

FIG. 6 shows an example of a current-voltage characteristic diagram of the power supply circuit for explaining the present invention. Characteristic VL
A represents a current-voltage characteristic of electric power generated at both ends of the antenna. The characteristic VL1 is a voltage required across the antenna when the resistance R01 is large in the power supply circuit shown in FIG. On the other hand, the characteristic VL2 is a voltage required across the antenna when the resistance R01 is small in the power supply circuit shown in FIG.

For example, when a reader / writer having a current-voltage characteristic as shown in the characteristic VLA and an antenna mounted on a non-contact type IC card are used, the withstand voltage of the element constituting the power supply circuit is VBDM. , The resistor R01
In the characteristic VL1 when the voltage is increased, the voltage VBD1 generated between the antenna terminals exceeds the withstand voltage VBDM, but the characteristic VL when the resistance R01 is decreased.
2, the voltage VBD2 generated between the antenna terminals does not exceed the withstand voltage VBDM. That is, it is possible to make the voltage generated between the antenna terminals not exceed the withstand voltage of the elements constituting the power supply circuit by reducing the resistance R01.

On the other hand, by reducing the resistance R01, the attenuation factor of the current change of the transmission circuit is increased by the above-mentioned formula 1. However, when the current change that can be received by the reader / writer is ITD, by making the current change IDLT shown in the above equation 1 larger than ITD, that is, when the following equation 2 is satisfied, the contactless IC card is used. Data can be sent to the reader / writer.

[0028]

## EQU00002 ## I01> ITD.times. (R01 + ROUT) / R01 (2) This is because if the current source I01 constituting the transmission circuit is a current source satisfying the above equation 2, the transmission to the reader / writer is performed. It means that it will be possible. Therefore, by reducing the resistance R01, the antenna terminals LA and L
It is possible to prevent the voltage generated during B from exceeding the withstand voltage of the elements that form the power supply circuit and the like, and to enable stable transmission to the reader / writer.

FIG. 7 shows an embodiment of a power supply circuit and a transmission circuit mounted on the semiconductor integrated circuit device according to the present invention. In this embodiment, the power supply circuit shown in FIG. 9 described in [Document 3] has NMOS transistors M11 to M
17, resistors R11 to R14, and an operational amplifier circuit A11
And a reference voltage source VREF, and the embodiment of FIG. 4 is applied to full-wave rectification.

The diode D02 shown in FIG.
The NMOS transistor M11, which corresponds to the MOS transistor M12 and is for full-wave rectification, has its source-drain path connected between the antenna terminal LA and the output terminal OUT1 and its gate connected to the antenna terminal LB. The NMOS transistor M01 and the resistor R0 shown in FIG.
1 is the NMOS transistor M13 and the resistor R11 in FIG.
The source-drain path of the NMOS transistor M15 for full-wave rectification is connected between the antenna terminal LB and the output terminal OUT1.

The voltage detection circuit G01 shown in FIG. 4 is composed of the following circuit as in FIG. 9 described in [Document 3]. A voltage dividing resistor R is provided between the output terminals OUT1 and OUT2.
13 and R14 are provided, and these voltage dividing resistors R13 and R1 are provided.
The divided voltage obtained at the connection point of 4 is the operational amplifier circuit A11.
To the non-inverting input (+) of. This operational amplifier circuit A
A reference voltage source VREF is provided between the inverting input (-) of 11 and the output terminal OUT2.

The voltage-controlled current source G02 shown in FIG. 4 is composed of the following circuit as in FIG. 9 described in [Document 3]. NMOS whose gate receives the output of the operational amplifier circuit A11
It is composed of a transistor M17. Similar to the PMOS transistors M23 and M25 shown in FIG. 9 of [Document 3], an NMOS transistor M17 and a resistor R11 and an NMOS transistor M17 and a resistor R12.
Between the gate, the NMOS whose gate is connected to the antenna terminal LA
A unidirectional function composed of a transistor M14 and M16 whose gate is connected to the antenna terminal LB is added.

The diode D01 constituting the above-mentioned transmission circuit of FIG. 4 corresponds to the NMOS transistor M18, and the source and drain of the NMOS transistor M19 are connected to the antenna terminal LB for full-wave rectification. In addition, the switch S01 and the current source I01 forming the transmission circuit of FIG.
It corresponds to 0, and realizes the function of the switch S01 and the current source I01 by controlling the voltage applied to its gate.

As described above, by replacing the diode with the NMOS transistor that performs the switching operation and performing the full-wave rectification operation, the stable output voltage VO with high efficiency can be obtained.
It is possible to generate a UT, and as shown in FIG.
As described with reference to FIGS. 5 and 6, the resistors R11 and R1 are
By setting the resistance value of 2, it is possible to prevent the voltage generated between the antenna terminals LA and LB from exceeding the withstand voltage of the elements constituting the power supply circuit, etc., and to enable stable transmission to the reader / writer. Become.

Although the present invention has been specifically described based on the embodiments above, it is needless to say that the present invention is not limited to the above embodiments and various modifications can be made without departing from the scope of the invention. Absent. For example, various specific embodiments of the operational amplifier circuit can be adopted. In the non-contact type IC card of FIG. 2, the power supply circuit, the internal circuit and the signal processing circuit may be composed of a plurality of semiconductor integrated circuits. Also, the configuration of the power supply circuit can be applied to the configurations of various power supply circuits shown in [Document 3].

[0036]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.

That is, a first input terminal and a second input terminal to which an AC voltage is applied are provided, the drain (or collector) is connected to the second input terminal, and the gate (or base) and drain (or collector) are connected. A first rectifying transistor, which is connected via a first resistance means and allows a rectifying current to flow between the first input terminal and the second input terminal,
A first voltage controlled current source that forms a current in response to a control voltage and supplies it to the first resistance means, and a rectified voltage obtained on the source (or emitter) side of the first rectifying transistor match a predetermined reference voltage. A first voltage detecting means for forming the control voltage, and a first unidirectional element for flowing a current corresponding to the rectified current between the first input terminal and a first output terminal for outputting a rectified voltage. A source (or emitter) of the first rectifying transistor is connected to a second output terminal for outputting a rectified voltage, and a voltage generated between the first and second input terminals constitutes the circuit. By setting the resistance value of the first resistance means so as not to exceed the withstand voltage, it is possible to obtain a highly efficient and stable smoothed voltage and transmit the current change of the transmission circuit to the reader / writer.

[Brief description of drawings]

FIG. 1 is an example of an operation waveform at the time of data transmission when the limiter circuit and the transmission circuit of [Document 1] are applied to a semiconductor integrated circuit device mounted on a non-contact type IC card.

FIG. 2 is a block diagram showing an embodiment of a non-contact type IC card according to the present invention.

FIG. 3 is a current-voltage characteristic of a reader / writer and an antenna for explaining the present invention.

FIG. 4 is a basic circuit configuration diagram of an embodiment of a power supply circuit and a transmission circuit mounted in the semiconductor integrated circuit device according to the present invention and an equivalent circuit of a reader / writer and an antenna mounted in a non-contact type IC card. .

FIG. 5 is a basic circuit configuration diagram of another embodiment of a power supply circuit and a transmission circuit mounted on the semiconductor integrated circuit device according to the present invention and an equivalent circuit of an antenna mounted on a reader / writer and a non-contact type IC card. Is.

FIG. 6 is an example of current-voltage characteristics of a power supply circuit for explaining the present invention.

FIG. 7 is an example of a power supply circuit and a transmission circuit mounted on the semiconductor integrated circuit device according to the present invention.

[Explanation of symbols]

M01, M11 to M20 ... MOS transistor, D0
1, D02 ... Diode, R01, R11 to R14 ... Resistor, V01 ... AC voltage source, ROUT ... Output impedance, I01, I02 ... Current source, S01, S02 ... Switch, G01 ... Voltage detection circuit, G02 ... Voltage controlled current source ,
VREF ... Reference voltage source, A11 ... Operational amplifier circuit, RW ...
Reader / writer, CA ... IC card, LRW, LCA ...
Antenna, RECT ... Voltage generation means, TR ... Communication means,
MC: signal processing and data holding means.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G06K 19/00 J (72) Inventor Masaru Kubota 5-22-1 Kamimizumotocho, Kodaira-shi, Tokyo Hitachi Ultra LSI Systems Inc. (72) Inventor Kazuhiro Matsushita 5-22-1 Kamimizuhonmachi, Kodaira-shi, Tokyo Hitachi Ultra LSI Systems Inc. (72) Invention Hajime Kinoda 5-20-1 Kamimizumotocho, Kodaira-shi, Tokyo F-term within Hitachi Semiconductor Group, Inc. (reference) 5B035 AA00 BB09 CA12 CA22 CA23 5G013 AA07 BA02 CB02 DA05 5G053 AA09 BA04 CA05 EA09 EC03 FA06 5K012 AC06 AC08 AC10 AE02 BA02

Claims (12)

[Claims] 1. A first input terminal and a second input terminal to which an AC voltage is applied, and a drain (or collector) connected to the second input terminal, and a gate (or base) and a drain (or collector) are provided. A first rectifying transistor that is connected through a first resistance means and flows a rectified current between the second input terminal and the second output terminal; and a current that responds to a control voltage is formed to form the first resistance means. A first voltage control current source supplied to the first rectifying transistor, and first voltage detecting means for forming the control voltage so that the rectified voltage obtained on the source (or emitter) side of the first rectifying transistor matches a predetermined reference voltage, A first input terminal and a first that outputs a rectified voltage
A first unidirectional element that causes a current corresponding to the rectified current to flow between the first unidirectional element and an output terminal, and the source (or emitter) of the first rectifier transistor outputs a rectified voltage.
It has a first transmitting function of being connected to an output terminal and transmitting information to the outside by changing its self-impedance, and a voltage generated between the first and second input terminals is a withstand voltage of an element constituting the circuit. A semiconductor integrated circuit device in which the resistance value of the first resistance means is set so as not to exceed the above. 2. The first rectifying transistor according to claim 1, wherein the first rectifying transistor comprises a first rectifying MOSFET, and the first unidirectional element receives a second input terminal at a gate thereof.
A semiconductor integrated circuit device comprising an OSFET, wherein the first voltage controlled current source is provided between the first output terminal and the gate of the first rectifying transistor. 3. The method according to claim 2, wherein the first transmission function is
A semiconductor integrated circuit device having a configuration in which a second unidirectional element, a first switch function, and a first current source are connected in series between a second input terminal and a first output terminal. 4. The method according to claim 2, wherein the first transmission function is
A semiconductor integrated circuit device having a configuration in which a second unidirectional element, a first switch function, and a first current source are connected in series between a second output terminal and a first output terminal. 5. The semiconductor integrated circuit device according to claim 3, wherein the first switch function and the first current source are composed of a second MOSFET controlled by a voltage applied to a gate. . 6. The semiconductor integrated device according to claim 1, wherein the first input terminal and the second input terminal are externally connected to an antenna for generating the AC voltage. Circuit device. 7. An antenna for receiving signals and power,
A power supply circuit that generates an internal voltage from the electric power received by the antenna, an internal circuit that operates with the internal voltage formed by the power supply circuit, and that processes a signal received by the antenna and saves data, and the power supply circuit A receiving circuit that operates at the internal voltage formed by the above, and that receives a signal through the antenna, and a transmitting circuit that operates at the internal voltage formed by the power supply circuit and that transmits a signal through the antenna. The power supply circuit includes a first input terminal and a second input terminal to which an alternating voltage generated by the antenna is applied, a drain (or collector) connected to the second input terminal, and a gate (or base). ) And the drain (or collector) are connected via the first resistance means, and a rectification current is caused to flow between the second input terminal and the second output terminal. And a first voltage controlled current source that forms a current in response to a control voltage and supplies it to the first resistance means, and a rectified voltage obtained on the source (or emitter) side of the first rectifying transistor is a predetermined reference voltage. And a first unidirectionality that causes a current corresponding to the rectified current to flow between the first input terminal and the first output terminal that outputs the rectified voltage, and the first voltage detection unit that forms the control voltage so that An element, the source (or emitter) of the first rectifying transistor is connected to the second output terminal that outputs the rectified voltage, and has a first transmitting function of transmitting information to the outside by changing the self impedance. However, the resistance value of the first resistance means is set so that the voltage generated between the first and second input terminals does not exceed the withstand voltage of the elements forming the circuit. Apparatus. 8. The first rectifying transistor according to claim 7, wherein the first rectifying transistor comprises a first rectifying MOSFET, and the first unidirectional element receives a second input terminal at a gate thereof.
A contactless electronic device comprising an OSFET, wherein the first voltage controlled current source is provided between the first output terminal and the gate of the first rectifying transistor. 9. The method according to claim 8, wherein the first transmission function is
A non-contact type electronic device having a configuration in which a second unidirectional element, a first switch function, and a first current source are connected in series between a second input terminal and a first output terminal. 10. The first transmission function according to claim 8, wherein a second unidirectional element, a first switch function, and a first current source are connected in series between the second output terminal and the first output terminal. A non-contact type electronic device having the above configuration. 11. The method according to claim 9 or 10, wherein:
The contactless electronic device, wherein the switch function and the first current source are composed of a second MOSFET controlled by a voltage applied to a gate. 12. The non-contact device according to claim 7, wherein the first input terminal and the second input terminal are externally connected to an antenna for generating the AC voltage. Type electronic device.