WO2007138690A1

WO2007138690A1 - Noncontact type electronic device and semiconductor integrated circuit device mounted on same

Info

Publication number: WO2007138690A1
Application number: PCT/JP2006/310855
Authority: WO
Inventors: Kazuki Watanabe
Original assignee: Hitachi, Ltd.
Priority date: 2006-05-31
Filing date: 2006-05-31
Publication date: 2007-12-06
Also published as: JPWO2007138690A1; JP4759053B2

Abstract

There has been problems of deterioration of performance, accuracy and the like of circuits mounted inside other than a noncontact type electronic device, due to heat generated by the noncontact type electronic device by excessive power supplied thereto. A capacitor (C1) and a capacitor (C2) are connected in series to the terminals on the both sides of an antenna (L0) mounted on the noncontact type electronic device (B1), a charge/discharge control circuit (B14) is connected to the contact point of the capacitor (C1) and the capacitor (C2), the resonance frequency is controlled by changing the charges accumulated in the capacitor (C1) and the capacitor (C2), and excessive power supply is suppressed.

Description

Non-contact electronic device and semiconductor integrated circuit device mounted thereon

TECHNICAL FIELD [0001] The present invention relates to a technology of a non-contact type electronic device, and in particular, a technology effective when applied to a non-contact type electronic device typified by an IC card or an IC tag and a semiconductor integrated circuit device mounted thereon. It is about.

Background art

[0002] As technologies studied by the present inventors, for example, the following technologies can be considered in non-contact type electronic devices such as IC cards, IC tags, RFIDs, and mobile phones.

[0003] Non-contact type electronic devices having a semiconductor integrated circuit device having functions such as a CPU and a memory inside are becoming widespread in the fields of transportation and logistics. Although not particularly limited, the contactless electronic device does not have a power source such as a battery, and operates by generating power from electromagnetic waves received by an antenna. The non-contact electronic device receives data transmitted by modulating electromagnetic waves from a reader / writer (interrogator), and further performs signal processing on the received data by a CPU, a memory, or the like. As a result, the electromagnetic wave received by the antenna is modulated by changing the load between the antenna terminals according to the obtained data, and the data is transmitted to the reader / writer.

In such a contactless electronic device, a capacitor and a variable capacitive element are connected in series between the antenna terminals, and a resonance voltage is controlled by applying a control voltage to the variable capacitive element, whereby the contactless electronic device There is a technique for suppressing the power supplied to the battery (see, for example, Patent Document 1).

[0005] In addition, according to the power supplied to the non-contact type electronic device, the resonance frequency is changed by logically switching the capacitance connected between the antenna terminals, and the power supplied to the non-contact type electronic device. There is a technique for suppressing the above (for example, see Patent Document 2). Furthermore, Patent Document 2 describes that the resonance frequency is changed stepwise by switching a plurality of capacitors.

Patent Document 1: Japanese Patent Laid-Open No. 9-147070

Patent Document 2: JP 2005-204493 A Disclosure of the invention

Problems to be solved by the invention

[0006] By the way, as a result of studies made by the inventor of the non-contact electronic device as described above, the following has become apparent.

[0007] In recent years, a sensor circuit that detects a temperature or the like is mounted on a non-contact electronic device that operates by generating an electromagnetic force power source received by an antenna, and according to data transmitted from a reader / writer. Some sensors measure the sensor circuit and can transmit the measurement data to the reader / writer by the above modulation operation.

[0008] A non-contact type electronic device operates by generating a power source by rectifying and smoothing an electromagnetic wave to which a reader / writer force is also supplied. Generally, since the electric power supplied to the non-contact type electronic device changes depending on the distance between the reader / writer and the non-contact type electronic device, the degree of self-heating of the non-contact type electronic device changes.

[0009] For example, when a temperature sensor circuit is mounted on such a non-contact type electronic device, the amount of self-heating is changed according to the communication distance, so that an error occurs in the temperature measured by the temperature sensor circuit. There was a problem that the measurement results could not be obtained.

[0010] In view of this, the present inventors have studied a technique for preventing excessive power from being supplied to the non-contact electronic device by controlling the resonance frequency according to the power received by the non-contact electronic device. It came to do.

[0011] However, when changing the resonance frequency using a variable capacitance element, it is necessary to use some means V and mount the variable capacitance element that can sufficiently change the resonance frequency in the non-contact type electronic device. There is. Although it is preferable to arrange a variable capacitance element in a semiconductor integrated circuit device mounted in a non-contact type electronic device, the resonance frequency is usually set in a semiconductor manufacturing process used for mounting a logic circuit or the like. In some cases, a variable capacitance element that can be changed sufficiently was installed.

[0012] In addition, when the resonant capacitance is logically switched, it is necessary to detect the power received by the non-contact electronic device and binarize the received power level. For example, when the electric power received by the non-contact type electronic device exceeds a predetermined level, the resonance capacitance is logically switched. However, as a result of switching the resonance capacitance, the received power of the contactless electronic device is reduced to a predetermined level. If it falls below the bell, the resonance capacity is controlled to return to the original value. However, since the received power level again exceeds the predetermined level, the resonance capacity is switched. As described above, when the received power level is close to the level at which the resonance capacitor is switched, the switching operation of the resonance capacitor is repeated, and the power received by the non-contact type electronic device may not be stable.

[0013] As described above, although there has been a resonance frequency control means for suppressing the non-contact type electronic device from generating heat due to excessive electric power supplied to the non-contact type electronic device, the general semiconductor integration There were problems such as restrictions on mounting on circuit devices and deterioration of stability in boundary conditions.

Accordingly, an object of the present invention is to provide a circuit technique capable of stably controlling the power received by the non-contact type electronic device.

[0015] The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

Means for solving the problem

[0016] Among the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.

That is, the non-contact electronic device according to the present invention and the semiconductor integrated circuit device mounted thereon include a resonance capacitance control circuit. In the resonant capacitance control circuit, a first capacitor and a second capacitor are connected in series between a first antenna terminal and a second antenna terminal to which an antenna is connected, and the first capacitor and the second capacitor are connected. The charge / discharge control circuit is connected to the connection point of the capacity. The charge / discharge control circuit controls the charge accumulated in the first capacitor when the potential of the first antenna terminal is higher than the potential of the second antenna terminal, and controls the second antenna. When the potential of the terminal is higher than the potential of the first antenna terminal, the resonance between the first antenna terminal and the second antenna terminal is controlled by controlling the charge accumulated in the second capacitor. Control the capacitance value.

The invention's effect

[0018] The effects obtained by typical ones of the inventions disclosed in the present application will be briefly described as follows. That is, it is possible to control the resonance frequency of the resonance circuit constituted by the antenna and the resonance capacitance control circuit, and to suppress excessive power supply to the rectifier circuit.

Brief Description of Drawings

FIG. 1 is a block diagram showing a basic configuration of a contactless electronic device and a semiconductor integrated circuit device according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing configurations of a non-contact electronic device and a semiconductor integrated circuit device, a wiring board, and a reader / writer according to Embodiment 1 of the present invention.

FIG. 3 is a circuit diagram showing a configuration example of a resonance capacitance control circuit mounted on the semiconductor integrated circuit device according to the first embodiment of the present invention.

IV] is a circuit diagram showing a configuration example of a resonance capacitance control circuit mounted on the semiconductor integrated circuit device according to the second embodiment of the present invention.

FIG. 5 is a diagram showing an operation waveform of each terminal voltage of the resonance capacitance control circuit shown in FIG.

FIG. 6 is a circuit diagram showing a configuration example of a resonant capacitance control circuit mounted on a semiconductor integrated circuit device according to a third embodiment of the present invention.

FIG. 7 is a circuit diagram showing a configuration example of a resonant capacitance control circuit mounted on a semiconductor integrated circuit device according to a fourth embodiment of the present invention.

FIG. 8 is a block diagram showing a configuration example of a resonant capacitance control circuit and a rectifying / smoothing circuit mounted on a semiconductor integrated circuit device according to a fifth embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof will be omitted.

[0022] (Embodiment 1)

FIG. 1 is a block diagram showing a basic configuration of a non-contact electronic device and a semiconductor integrated circuit device according to Embodiment 1 of the present invention.

First, an example of the configuration of the non-contact electronic device and the semiconductor integrated circuit device according to the first embodiment will be described with reference to FIG. The contactless electronic device according to the first embodiment is, for example, an IC force card, an IC tag, an RFID, or a mobile phone. In FIG. 1, B1 is a non-contact type electronic device, B2 is a semiconductor integrated circuit device mounted on the non-contact type electronic device B1, and LO is an antenna mounted on the non-contact type electronic device B1. The semiconductor integrated circuit device B2 has a resonance capacitance control circuit B3, a rectifying / smoothing circuit B4, and an internal circuit B5, and has antenna terminals LA and LB for connecting the antenna LO. In Fig. 1, the antenna LO is not necessarily connected because it is adjusted in consideration of the force resonance capacitance control circuit B3 in which the resonance capacitance CO is connected in parallel and the parasitic capacitance.

FIG. 2 shows a structural example of the non-contact type electronic device B1. Figure 2 shows an example of an IC card, but this is not a limitation.

[0026] The non-contact type electronic device B1 is in the form of a card by a resin-molded printed circuit board B10. The antenna LO that receives electromagnetic waves from the external reader / writer B13 is constituted by a spiral coil B11 formed by the wiring of the printed board B10. In the semiconductor integrated circuit device B2 composed of one IC chip B12, a coil B11 serving as an antenna LO is connected to the IC chip B12. The antenna LO (coil B11) receiving the electromagnetic wave from the reader / writer B13 outputs a high-frequency AC signal to the antenna terminals LA and LB. This AC signal is partially modulated by an information signal (data).

[0027] The present invention is typically applied to a non-contact type electronic device having no external input / output terminal on the surface of the non-contact type electronic device. Of course, you may use for the dual type non-contact type electronic device which has both a non-contact interface and an input / output terminal. Although not particularly limited, the semiconductor integrated circuit device B2 is formed on a single semiconductor substrate such as single crystal silicon or the like by a known semiconductor integrated circuit device manufacturing technique.

In FIG. 1, the resonance capacitance control circuit B3 is configured by the antenna LO, the resonance capacitance control circuit B3, and the resonance capacitance CO by controlling the resonance capacitance according to the power supplied between the antenna terminals. The resonance frequency of the resonance circuit is changed.

[0029] The rectifying / smoothing circuit B4 includes a rectifying circuit and a smoothing capacitor, and may have a regulator function. The regulator function controls so that the voltage generated by the rectifier circuit and the smoothing capacitor does not exceed a predetermined voltage level. The output voltage of the rectifying / smoothing circuit B4 is supplied as the power supply voltage VDD of the internal circuit B5.

[0030] The internal circuit B5 includes a receiving circuit B6, a transmitting circuit B7, a control unit B8, and a memory B9. . The reception circuit B6 demodulates the information signal superimposed on the AC signal received by the antenna LO provided in the non-contact type electronic device B1, and supplies it to the control unit B8 as a digital information signal. The transmission circuit B7 receives the information signal of the digital signal output from the control unit B8, and modulates the AC signal received by the antenna LO with the information signal. The reader / writer B13 (see FIG. 2) receives the information signal from the control unit B8 in response to the reflection of the electromagnetic wave from the antenna LO being changed by the modulation. The memory B9 is used for recording information data and transmission data demodulated with the control unit B8.

FIG. 3 is a basic configuration diagram of a resonance capacitance control circuit B3 mounted on the semiconductor integrated circuit device B2 according to the present invention.

In the semiconductor integrated circuit device B2, the resonance capacitance control circuit B3 is connected between the antenna terminal LA (first antenna terminal) and the antenna terminal LB (second antenna terminal). The resonant capacity control circuit B3 has a capacity C1 (first capacity) and a capacity C2 (second capacity) between the antenna terminals LA and LB that connect the antenna mounted on the non-contact type electronic device B1. Connected in series, the connection point between capacitors C1 and C2 and charge / discharge control circuit B14 connected to antenna terminals LA and LB are connected. The charge / discharge control circuit B14 includes variable resistors R1 and R2 connected in series between the antenna terminals LA and LB, and a connection point between the variable resistors R1 and R2 and a connection point between the capacitors C1 and C2 are connected. . A rectifying / smoothing circuit B4 mounted on the semiconductor integrated circuit device B2 is connected to the antenna terminals LA and LB, and the power supply voltage VDD is output between the output terminal OUT and the ground terminal.

[0033] When the voltage at the antenna terminals LA and LB is lower than a predetermined level, the charge / discharge control circuit B14 controls the resistances of the resistors R1 and R2 connected in parallel to the capacitors C1 and C2 so as to increase. Thus, the current is controlled so as to hardly flow through the resistors R1 and R2. As a result, it can be approximated that the capacitors C1 and C2 are connected in series between the antenna terminals, and a capacitor having a capacitance value half that of the capacitor C1 or C2 is connected. In the following, although not limited to this, it is assumed that the capacitance values of the capacitors C1 and C2 are equal.

[0034] On the other hand, when the voltage between the antenna terminals higher than the potential of the antenna terminal LA is higher than a predetermined voltage level, the charge / discharge control circuit B14 The resistance R2 connected in parallel with the capacitor C2 is controlled to be small according to the voltage level between the terminals. In addition, when the voltage between the antenna terminals, which is higher than the potential of the antenna terminal LA, is higher than a predetermined voltage level, it is connected in parallel to the capacitor C1 according to the voltage level between the antenna terminals. The resistance R1 is controlled to be small.

That is, when the potential of the antenna terminal LA is higher than the potential of the antenna terminal LB, the charge accumulated in the capacitor C 1 is controlled, and when the potential of the antenna terminal LB is higher than the potential of the antenna terminal LA, the capacitance By controlling the charge stored in C2, the resonant capacitance between antenna terminal LA and antenna terminal LB is controlled.

[0036] Thereby, when the voltage level force between the antenna terminals is larger than the predetermined voltage level, the charges accumulated in the capacitors C1 and C2 are controlled, and the capacitance connected between the antenna terminals changes. For example, when the resistance R1 or R2 is controlled to a very small resistance value, it can be approximated to a state where a capacitance having a capacitance value equivalent to the capacitance C2 or the same capacitance 1 is connected between the antenna terminals.

[0037] According to the above-described operation, the resonance capacitance can be controlled in a range from a capacitance value half of the capacitance C1 to a capacitance value equivalent to the capacitance C1, according to the voltage level generated between the antenna terminals. The resonance frequency of the resonance circuit configured by the resonance capacitance control circuit B3 can be controlled.

[0038] For example, if the capacitance values of the capacitors C1 and C2 are set to twice the capacitance value that resonates with the frequency of the electromagnetic wave supplied to the antenna LO, the voltage level generated between the antenna terminals becomes a predetermined voltage. If the voltage level is lower than the level, the maximum power can be received by resonating.If the voltage level generated between the antenna terminals is higher than the specified voltage level, the resonance frequency can be lowered by increasing the resonance capacity of the antenna terminal. The electric power supplied to the rectifying / smoothing circuit B4 can be reduced.

[0039] As a result, excessive power is not supplied to the rectifying / smoothing circuit B4, and the heat generation of the chip can be reduced. Furthermore, since it becomes easy to control the voltage amplitude generated between the antenna terminals to be small, it is easy to protect the withstand voltage of the elements constituting the rectifying and smoothing circuit B4.

[0040] As described above, the charge / discharge control circuit B14 is connected to the capacitors C1 and C2 connected between the antenna terminals. In this example, the resonance capacitance between the antenna terminals is controlled by controlling the resistance connected in parallel to the low-potential side capacitor, but the resistance connected in parallel to the high-potential side capacitance is controlled. However, the same effect can be obtained.

[0041] (Embodiment 2)

FIG. 4 is a circuit configuration diagram showing another embodiment of the resonance capacitance control circuit B3 mounted in the semiconductor integrated circuit device B2 according to the present invention. This shows another circuit configuration example of the charge / discharge control circuit B14 mounted on the resonance capacitance control circuit B3 shown in FIG.

[0042] The resonant capacitance control circuit B3 connected between the antenna terminals LA and LB has capacitors C1 and C2 between the antenna terminals LA and LB that connect the antenna mounted on the non-contact type electronic device B1. Are connected in series, and the charge / discharge control circuit B14 is connected to the connection point of the capacitors C1 and C2 and the antenna terminals LA and LB. The charge / discharge control circuit B14 has a MOS transistor Ml (first MOS transistor) whose gate terminal is connected to the antenna terminal LB and a MOS transistor M2 (second MOS transistor) whose gate terminal is connected to the antenna terminal LA. In this configuration, a variable resistor R3 (variable resistor element) is connected between the connection point of the capacitors C1 and C2 and the connection point of the MOS transistors Ml and M2.

FIG. 5 shows an example of the operation waveform of each terminal voltage in FIG. This shows the operating waveform of each terminal voltage based on the potential at the connection point of the MOS transistors Ml and M2, W0 is the voltage waveform at the connection point of the MOS transistors Ml and M2, and W1 is the antenna terminal LA. Voltage waveform, W2 is the voltage waveform at the antenna terminal LB, W3 and W4 are the voltage waveforms at the connection point of the capacitors C1 and C2, W3 is the voltage waveform when the variable resistance R3 is extremely large, and the resistance value, W4 is variable Show the voltage waveform when resistance R3 is very small and resistance! / Speak.

[0044] When the potential of the antenna terminal LA is higher than the potential of the antenna terminal LB, the MOS transistor M2 is turned on and the MOS transistor Ml is turned off. Also, when the potential of the antenna terminal LB is higher than the potential of the antenna terminal LA, the MOS transistor Ml is turned on and the MOS transistor M2 is turned off.

[0045] By the operation of the MOS transistors Ml and M2, the connection point of the MOS transistors Ml and M2 is controlled to be equal to the potential of the antenna terminal LA or LB on the low potential side. The voltage waveform is Wl and W2. Therefore, the variable resistor R3 operates in a state where it is connected in parallel with the low-potential side capacitor C1 or C2, and when the variable resistor R3 has a very large resistance value, the variable resistor R3 can be ignored. As shown in W3, the connection point between capacitors C1 and C2 is half the voltage between antenna terminals. Conversely, when the variable resistor R3 has a very small resistance value, it is equivalent to a state in which both ends of the variable resistor R3 are short-circuited.As shown in W4, the connection point of the capacitors C1 and C2 is WO and It is almost equal and can be approximated to the state where the capacitor C1 or C2 is connected between the antenna terminals. According to the resistance value of the variable resistor R3, the resonance capacitance can be controlled in the range from half the capacitance value of the capacitance C1 to the capacitance value equivalent to the capacitance C1, and is configured by the antenna LO and the resonance capacitance control circuit B3 This shows that the resonant frequency of the resonant circuit can be controlled.

[0047] Although the circuit shown in FIG. 3 requires two variable resistors, it becomes possible to share the variable resistors and reduce variations due to the variable resistors. Here, the threshold voltages of the MOS transistors Ml and M2 can also contribute to the characteristic error. However, since the MOS transistors Ml and M2 are turned on / off, the influence on the resonant capacitance characteristics is not affected.

Very small.

[0048] (Embodiment 3)

FIG. 6 is a circuit configuration diagram showing another embodiment of the resonance capacitance control circuit B3 mounted on the semiconductor integrated circuit device B2 according to the present invention. This is an example in which the variable resistor R3 constituting the charge / discharge control circuit B14 mounted on the resonance capacitance control circuit B3 shown in FIG. 4 is configured by a MOS transistor.

[0049] The resonant capacitance control circuit B3 connected between the antenna terminals LA and LB has capacitors C1 and C2 between the antenna terminals LA and LB that connect the antenna mounted on the non-contact type electronic device B1. Are connected in series, and the connection point of the capacitors C1 and C2 and the charge / discharge control circuit B14 connected to the antenna terminals LA and LB are connected.

[0050] Further, the charge / discharge control circuit B14 has a MOS transistor Ml having a gate terminal connected to the antenna terminal LB and a MOS transistor M2 having a gate terminal connected to the antenna terminal LA connected in series, and a connection point between the capacitors C1 and C2. And the connection point of MOS transistors Ml and M2, A MOS transistor M3 (variable resistance element, seventh MOS transistor) is connected, and a voltage detection circuit B15 is connected between the antenna terminals LA and LB. At this time, the connection point of MOS transistors Ml and M2 is connected to the ground terminal.

[0051] In the voltage detection circuit B15, a MOS transistor M4 (first rectifier element) having a gate terminal and a drain terminal connected is connected between the antenna terminal LA and the output terminal OUT2, and the antenna terminal LB and the output terminal are connected. Connect a MOS transistor M5 (second rectifier) with the gate and drain terminals connected between OUT2, connect a capacitor C3 between the output terminal OUT2 and the ground terminal, and connect the output terminal OUT2 and the ground terminal. Connect the connection point of resistors R4 and R5 connected in series between them to the non-inverting input terminal (+) of the operational amplifier circuit A1, and input the reference voltage VI to the inverting input terminal (one) of the operational amplifier circuit A1. In this configuration, the output terminal N1 of the operational amplifier circuit A1 is input to the gate terminal of the MOS transistor M3.

In FIG. 6, the operational amplifier circuit A 1 detects the power supplied between the antenna terminals as a voltage generated at the output terminal OUT 2 and controls the current flowing through the MOS transistor M 3.

[0053] When the voltage generated at the output terminal OUT2 is lower than the predetermined voltage level, that is, when the voltage generated at the antenna terminal is lower than the predetermined voltage level, no current flows through the MOS transistor M3. Capacitors C1 and C2 can be approximated in series between the terminals, and a capacitor with a capacitance value half that of capacitor C1 is connected.

[0054] Further, when the voltage generated at the output terminal OUT2 is higher than a predetermined voltage level, that is, when the voltage generated at the antenna terminal is higher than the predetermined voltage level, depending on the voltage generated at the output terminal OTU2 Since the current flowing through the MOS transistor M3 is controlled, the charge stored in the capacitors C1 and C2 is controlled, and the capacitance connected between the antenna terminals changes. For example, when the current flowing through the MOS transistor M3 is controlled to an extremely large current value, either the capacitor C1 or C2 is short-circuited, so that the capacity value equivalent to the capacity C1 is between the antenna terminals. Can be approximated to a connected state.

[0055] According to the above-described operation, the resonance capacitance can be controlled in a range from a capacitance value half of the capacitance C1 to a capacitance value equivalent to the capacitance C1, according to the voltage level generated between the antenna terminals. The resonant frequency of the resonant circuit composed of the tenor LO and resonant capacity control circuit B3 can be controlled.

[0056] For example, if the capacitance value of the capacitor C1 is set to twice the capacitance value that resonates with the frequency of the electromagnetic wave supplied to the antenna LO, the voltage level generated between the antenna terminals will be higher than the predetermined voltage level. If it is small, the maximum power can be received by resonating with the frequency of the electromagnetic wave, and if the voltage level generated between the antenna terminals is higher than the predetermined voltage level, the resonance frequency can be increased by increasing the resonance capacity of the antenna terminal. The power supplied to the rectifying / smoothing circuit B4 can be reduced.

[0057] When the polarity of the operational amplifier circuit A1 is reversed and the voltage level generated between the antenna terminals is larger than the predetermined voltage level, the on-resistance of the MOS transistor M3 is increased to resonate the antenna terminal. The resonance frequency may be controlled to be higher by reducing the capacitance.

Here, MOS transistor M2 is turned on only when the potential of antenna terminal LA is higher than the potential of antenna terminal LB, and MOS transistor Ml is turned on only when the potential of antenna terminal LB is higher than the potential of antenna terminal LA. Therefore, the MOS transistors Ml and M2 also operate as a rectifying element on the low potential side.

[0059] Further, a current flows through the MOS transistor M4 only when the potential of the antenna terminal LA is higher than the potential of the output terminal OUT2, and a current flows through the MOS transistor M5 only when the potential of the antenna terminal LB is higher than the potential of the output terminal OUT2. Since it flows, the MOS transistors M4 and M5 also operate as rectifiers on the high potential side.

[0060] From the above, the charge / discharge control circuit B14 also functions as a rectifier circuit, and the capacitor C3 functions as a smoothing capacitor. Therefore, the voltage generated at the output terminal OUT2 is transferred to the internal circuit B5 of the semiconductor integrated circuit device B2. Can be used as a power supply voltage. As a result, it is not necessary to mount the rectifying / smoothing circuit B4 independent of the resonance capacitance control circuit B3, and the chip area can be reduced.

[Embodiment 4]

FIG. 7 is a circuit configuration diagram showing another embodiment of the resonance capacitance control circuit B3 mounted in the semiconductor integrated circuit device B2 according to the present invention. This is the resonant capacitance control circuit shown in Fig. 3. 10 shows another circuit configuration example of the charge / discharge control circuit B14 mounted on B3.

[0062] The resonant capacitance control circuit B3 connected between the antenna terminals LA and LB has capacitors C1 and C2 between the antenna terminals LA and LB connecting the antenna arranged in the non-contact type electronic device B1. Are connected in series, and the connection point of the capacitors C1 and C2 and the charge / discharge control circuit B14 connected to the antenna terminals LA and LB are connected.

[0063] The charge / discharge control circuit B14 includes a MOS transistor M6 (third MOS transistor) in which a resistor R6 (first resistor) is connected between the antenna terminal LB and the gate terminal between the antenna terminals LA and LB. ) And a MOS transistor M7 (fourth MOS transistor) with a resistor R7 (second resistor) connected between the antenna terminal LA and the gate terminal, and between the gate terminal of the MOS transistor M6 and the ground terminal The MOS transistor M8 (fifth MOS transistor) with the gate terminal connected to the antenna terminal LB and the MOS transistor M10 (variable resistance element, seventh MOS transistor) with the gate terminal connected to the output terminal N1 of the voltage detection circuit B15 ) Are connected in series, and the MOS transistor M9 (sixth MOS transistor) has a gate terminal connected to the antenna terminal LA between the gate terminal of the MOS transistor M7 and the drain terminal of the MOS transistor M10. It is connected.

[0064] The voltage detection circuit B15 is configured to output a voltage corresponding to the voltage generated between the antenna terminals. For example, the voltage detection circuit B15 may have the circuit configuration illustrated in FIG. However, in order to connect to the ground terminal in the chip, a rectifier on the low potential side represented by MOS transistors Ml and M2 shown in FIG. 6 is also required.

[0065] In FIG. 7, the voltage detection circuit B15, depending on the voltage generated between the antenna terminals,

Controls the current flowing through MOS transistor M10. If the voltage generated between the antenna terminals is lower than the specified voltage level, the potential at the output terminal N1 will be low and no current will flow through the MOS transistor M10, so that the MOS transistors M6 and M7 have high gate potentials. Turn on. As a result, the voltage across one of the capacitors C1 and C2 is short-circuited between the antenna terminals, so that it can be approximated to a state where a capacitor having a capacitance value equivalent to that of the capacitor C1 is connected between the antenna terminals. become.

[0066] If the voltage generated between the antenna terminals is higher than a predetermined voltage level, the current flowing through the MOS transistor M10 is controlled according to the voltage generated at the antenna terminal. Therefore, the voltage generated in the resistor R6 or R7 is controlled to increase, and the gate voltages of the MOS transistors M6 and M7 are suppressed. As a result, since the current flowing through the MOS transistors M6 and M7 is controlled, the charge stored in the capacitors C1 and C2 is controlled, and the capacitance connected between the antenna terminals changes. For example, when the current flowing through the MOS transistors M6 and M7 is controlled to a very small current value, it can be approximated to the state where the capacitors C1 and C2 are connected in series between the antenna terminals, and the capacitance having a capacitance value half that of the capacitor C1 is obtained. It will be connected.

[0067] By the above operation, the resonance capacitance can be controlled in the range from the capacitance value equivalent to the capacitance C1 to the capacitance value half of the capacitance C1, according to the voltage level generated at the antenna terminal. The resonance frequency of the resonance circuit configured by the resonance capacitance control circuit B3 can be controlled.

[0068] Furthermore, when the voltage level generated between the antenna terminals becomes higher than a predetermined voltage level, it is possible to control the resonance frequency to be increased, so that excessive power is supplied. Can be suppressed, and the current flowing through the capacitor can be reduced, so that heat generation by the resonant capacitor can also be suppressed. This is particularly effective when the capacitors C1 and C2 are mounted on the semiconductor integrated circuit device B2.

[Embodiment 5]

FIG. 8 is a block diagram showing an embodiment of the resonant capacitance control circuit B3 and the rectifying / smoothing circuit B4 mounted on the semiconductor integrated circuit device B2 according to the present invention.

[0070] This is obtained by connecting the resonant capacitance control circuit B3 between the antenna terminals LA and LB, connecting the rectifying and smoothing circuit B4 to the antenna terminals LA and LB, and obtaining the output terminal OUT of the rectifying and smoothing circuit B4. In this configuration, the voltage suppressed by the regulator circuit B16 is obtained from the output terminal OUT3. As the resonance capacitance control circuit B3, for example, the circuits of FIGS. 3, 4, 6, and 7 in the first to fourth embodiments are used.

[0071] If the output voltage of the rectifying / smoothing circuit B4 cannot be sufficiently controlled by the resonance capacitance control circuit B3, the regulator circuit B16 can be mounted to stabilize the power supply voltage supplied to the internal circuit B5. good. As a result, it is possible to reduce chip heat generation by suppressing excessive power supply by the resonance capacitance control circuit B3, and to stabilize power supply voltage. Can be supplied to the internal circuit B5.

[0072] At this time, although not particularly limited, the voltage level at which the resonant capacitance control circuit B3 starts to control the resonant capacitance is made larger than the voltage level at which the regulator circuit B16 starts to suppress the output voltage. Adjustment of circuit characteristics is facilitated, which is preferable.

Similarly, also in the resonance capacitance control circuit B3 having the rectifying and smoothing function shown in FIG. 6, it is possible to mount a regulator at the output terminal OUT2.

[0074] While the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. It's possible that it's possible!

For example, in the embodiment described above, a force P-type MOS transistor in which the resonance capacitance control circuit is configured by an N-type MOS transistor may be used. Further, the location of the capacitors C1 and C2 for controlling the resonant capacitance is not limited to the semiconductor integrated circuit device B2, but may be arranged other than the semiconductor integrated circuit device B2, and moreover, In addition to the capacitors C1 and C2, other capacitors can be connected between the antenna terminals.

Industrial applicability

The present invention is suitable for application to non-contact electronic devices typified by IC cards and IC tags.

Claims

The scope of the claims

[1] with antenna,

A resonant capacitance control circuit connected to the antenna;

The resonant capacitance control circuit is

A first capacitor and a second capacitor are connected in series between a first antenna terminal and a second antenna terminal to which the antenna is connected,

A charge / discharge control circuit is connected to a connection point between the first capacitor and the second capacitor, and the charge / discharge control circuit is:

When the potential of the first antenna terminal is higher than the potential of the second antenna terminal, the charge accumulated in the first capacitor is controlled,

When the potential of the second antenna terminal is higher than the potential of the first antenna terminal, by controlling the charge accumulated in the second capacitor,

A contactless electronic device, wherein a resonance capacitance value between the first antenna terminal and the second antenna terminal is controlled.

[2] The contactless electronic device according to claim 1,

The charge / discharge control circuit includes:

Between the first antenna terminal and the second antenna terminal,

A first MOS transistor having a gate terminal connected to the second antenna terminal and a second MOS transistor having a gate terminal connected to the first antenna terminal are connected in series,

A connection point between the first capacitor and the second capacitor;

A contactless electronic device, wherein a variable resistance element is connected between a connection point of the first MOS transistor and the second MOS transistor.

[3] The contactless electronic device according to claim 1,

The charge / discharge control circuit includes:

Between the first antenna terminal and the second antenna terminal, A third MOS transistor in which a first resistor is connected between the second antenna terminal and the gate terminal;

A fourth MOS transistor having a second resistor connected between the first antenna terminal and the gate terminal is connected in series;

Between the gate terminal of the third MOS transistor and the gate terminal of the fourth MOS transistor,

A fifth MOS transistor having a gate terminal connected to the second antenna terminal and a sixth MOS transistor having a gate terminal connected to the first antenna terminal are connected in series,

A contactless electronic device, wherein a variable resistance element is connected between a connection point of the fifth MOS transistor and the sixth MOS transistor and a ground terminal.

[4] In the contactless electronic device according to claim 2 or 3,

The variable resistance element is:

The contactless electronic device, wherein a resistance value is controlled to be small when a voltage generated between the first antenna terminal and the second antenna terminal is larger than a predetermined voltage.

[5] In the contactless electronic device according to claim 2 or 3,

The variable resistance element is:

A contactless electronic device, wherein a resistance value is controlled to increase when a voltage generated between the first antenna terminal and the second antenna terminal is smaller than a predetermined voltage.

[6] In the contactless electronic device according to claim 2 or 3,

A voltage detection circuit that outputs a voltage corresponding to a voltage generated between the first antenna terminal and the second antenna terminal;

The variable resistance element is:

The output of the voltage detection circuit consists of a seventh MOS transistor connected to the gate terminal! A non-contact electronic device characterized by squeezing.

[7] In the contactless electronic device according to claim 2 or 3, A first rectifier element is connected between the first antenna terminal and the first output terminal; a second rectifier element is connected between the second antenna terminal and the first output terminal; The connection point between the first MOS transistor and the second MOS transistor is connected to the second output terminal, so that the first and second MOS transistors operate as rectifier elements,

A non-contact type electronic device, wherein a voltage generated between the first output terminal and the second output terminal is supplied as a power supply voltage to another circuit mounted therein.

[8] A semiconductor integrated circuit device mounted on a non-contact electronic device,

A resonant capacitance control circuit;

The resonant capacitance control circuit is

A first capacitor and a second capacitor are connected in series between a first antenna terminal and a second antenna terminal to which an antenna mounted on the contactless electronic device is connected,

A semiconductor integrated circuit device characterized by controlling a resonance capacitance value between the first antenna terminal and the second antenna terminal.

[9] The semiconductor integrated circuit device according to claim 8,

The charge / discharge control circuit includes:

Between the first antenna terminal and the second antenna terminal,

A first MOS transistor having a gate terminal connected to the second antenna terminal and a second MOS transistor having a gate terminal connected to the first antenna terminal are connected in series, A connection point between the first capacitor and the second capacitor;

A semiconductor integrated circuit device, wherein a variable resistance element is connected between a connection point of the first MOS transistor and the second MOS transistor.

[10] The semiconductor integrated circuit device according to claim 8,

The charge / discharge control circuit includes:

Between the first antenna terminal and the second antenna terminal,

A third MOS transistor in which a first resistor is connected between the second antenna terminal and the gate terminal;

A semiconductor integrated circuit device, wherein a variable resistance element is connected between a connection point of the fifth MOS transistor and the sixth MOS transistor and a ground terminal.

[11] The semiconductor integrated circuit device according to claim 9 or 10,

The variable resistance element is:

A semiconductor integrated circuit device, wherein a resistance value is controlled to be small when a voltage generated between the first antenna terminal and the second antenna terminal is larger than a predetermined voltage.

[12] The semiconductor integrated circuit device according to claim 9 or 10,

The variable resistance element is:

A semiconductor integrated circuit device, wherein a resistance value is controlled to increase when a voltage generated between the first antenna terminal and the second antenna terminal is smaller than a predetermined voltage.

[13] The semiconductor integrated circuit device according to claim 9 or 10, A voltage detection circuit that outputs a voltage corresponding to a voltage generated between the first antenna terminal and the second antenna terminal;

The variable resistance element is:

A semiconductor integrated circuit device comprising: a seventh MOS transistor having an output of the voltage detection circuit connected to a gate terminal.

The semiconductor integrated circuit device according to claim 9 or 10,

A first rectifier element is connected between the first antenna terminal and the first output terminal; a second rectifier element is connected between the second antenna terminal and the first output terminal; The connection point between the first MOS transistor and the second MOS transistor is connected to the second output terminal, so that the first and second MOS transistors operate as rectifier elements,

A semiconductor integrated circuit device, wherein a voltage generated between the first output terminal and the second output terminal is supplied as a power supply voltage to another circuit mounted therein.