JP4232434B2 - Semiconductor integrated circuit device, wireless communication terminal - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor integrated circuit device and a wireless communication terminal, and more particularly, to a semiconductor integrated circuit device and a wireless communication terminal capable of reducing the size of a chip and ensuring more preferable reception sensitivity.
[0002]
[Prior art]
In recent years, management systems for commuter pass information and electronic money information using non-contact IC cards have become widespread, and users can approach non-contact IC cards holding commuter pass information close to the ticket gates, for example, at ticket gates. It is possible to pass through the ticket gate by simply making it, or to pay the price of the product with electronic money simply by bringing a non-contact IC card holding electronic money information close to the reader / writer.
[0003]
By the way, there is a mobile phone as one of the items that the user always carries. As disclosed in the following patent document, when the above-described contactless IC card function is mounted on the mobile phone, the user can use the mobile phone. It is very convenient not only to make various communications such as calls and e-mails, but also to pass through the ticket gate or pay for goods.
[0004]
In addition, various proposals have been made to mount not only a non-contact IC card function but also a non-contact IC card reader / writer function on a terminal such as a mobile phone. In addition to causing the writer to read predetermined data, information stored in an external contactless IC card can be rewritten by using a mobile phone.
[0005]
Therefore, when the non-contact IC card reader / writer provided in the mobile phone or the like is realized by a single chip IC of CMOS (Complementary Metal Oxide Semiconductor), the mobile phone operates as a non-contact IC card on the chip. In addition to the circuit used sometimes, an antenna drive circuit as a transmission circuit for transmitting data to an external non-contact IC card and a reception circuit for receiving data transmitted from the external non-contact IC card are provided.
[0006]
Therefore, when the mobile phone operates as a non-contact IC card reader / writer and transmits data to an external non-contact IC card, the antenna drive circuit as a transmission circuit is driven, while the data is transmitted from the external non-contact IC card. When receiving the received data, the receiving circuit is driven, and data is transmitted to and received from an external non-contact IC card.
[0007]
[Patent Literature]
JP-A-11-213111
[0008]
[Problems to be solved by the invention]
However, the receiving circuit of such a non-contact IC card reader / writer formed on one chip is generally a half-wave rectifier circuit composed of a diode, a capacitor and the like, and the signal obtained by rectification is half-wave. Since it is a rectified signal, a large amount of AC component remains in the output to the subsequent detection amplifier and the like, and there is a problem that reception sensitivity is poor.
[0009]
In other words, since the AC component remains in the output of the receiving circuit, erroneous detection of data read from the non-contact IC card occurs.
[0010]
The present invention has been made in view of such a situation, and aims to reduce the size of a chip and to ensure more preferable reception sensitivity.
[0011]
[Means for Solving the Problems]
A semiconductor integrated circuit device of the present invention includes a first communication device that is in close proximity, an antenna that performs communication using electromagnetic induction, A drive circuit including a parasitic diode bridge circuit and operated by power supplied from a power supply unit, Of the transmission data signal representing the data to be transmitted to the first communication device, the transmission data signal whose amplitude is not inverted and the transmission carrier signal whose amplitude is not inverted are superimposed by the parasitic diode bridge circuit A drive circuit that superimposes a transmission data signal whose amplitude is inverted and a transmission carrier signal whose amplitude is inverted, and drives the antenna by a differential output based on the superimposed signals. And a detection amplifier that detects data transmitted from the first communication device based on a signal supplied from the antenna and rectified in the parasitic diode bridge circuit.
[0012]
The semiconductor integrated circuit device of the present invention includes a parasitic diode bridge circuit and , A resistor may be provided between the power supply units that supply power to the drive circuit.
[0013]
The semiconductor integrated circuit device of the present invention is When receiving an electromagnetic wave radiated from a second communication device that is close to the antenna, the antenna load is controlled based on predetermined data transmitted to the second communication device, You may make it further provide the modulation circuit which modulates the electromagnetic waves received in the antenna.
[0014]
The semiconductor integrated circuit device according to the present invention includes a switch for controlling the supply of power to the drive circuit. Between the parasitic diode bridge circuit and the power supply section You may make it provide further. In this case, the supply of power is cut off by the switch during a period in which predetermined data is transmitted to and received from the second communication device.
[0015]
The semiconductor integrated circuit device of the present invention includes a diode for controlling the supply of power to the drive circuit. Between the parasitic diode bridge circuit and the power supply section You may make it provide further. In this case, the diode is reverse-biased by the voltage generated by rectifying the electromagnetic wave radiated from the second communication device and received by the antenna in the parasitic diode bridge circuit formed in the drive circuit, thereby supplying power. Is cut off.
[0016]
A wireless communication terminal of the present invention includes a first communication device that is in close proximity, an antenna that performs communication using electromagnetic induction, A drive circuit including a parasitic diode bridge circuit and operated by power supplied from a power supply unit, Of the transmission data signal representing the data to be transmitted to the first communication device, the transmission data signal whose amplitude is not inverted and the transmission carrier signal whose amplitude is not inverted are superimposed by the parasitic diode bridge circuit The transmission data signal whose amplitude is inverted and the transmission carrier signal whose amplitude is inverted are superimposed, and the antenna is driven by the differential output based on each superimposed signal. Above A drive circuit and a detection amplifier that detects data transmitted from the first communication device based on a signal supplied from the antenna and rectified in the parasitic diode bridge circuit.
[0017]
The wireless communication terminal of the present invention includes a parasitic diode bridge circuit and , A resistor may be provided between the power supply units that supply power to the drive circuit.
[0018]
The wireless communication terminal of the present invention When receiving an electromagnetic wave radiated from a second communication device that is close to the antenna, the antenna load is controlled based on predetermined data transmitted to the second communication device, You may make it further provide the modulation circuit which modulates the electromagnetic waves received in the antenna.
[0019]
The wireless communication terminal according to the present invention includes a switch for controlling power supply to the drive circuit. Between the parasitic diode bridge circuit and the power supply section You may make it provide further. In this case, the supply of power is cut off by the switch during a period in which predetermined data is transmitted to and received from the second communication device.
[0020]
The wireless communication terminal of the present invention includes a diode that controls the supply of power to the drive circuit. Between the parasitic diode bridge circuit and the power supply section You may make it provide further. In this case, the diode is reverse-biased by the voltage generated by rectifying the electromagnetic wave radiated from the second communication device and received by the antenna in the parasitic diode bridge circuit formed in the drive circuit, thereby supplying power. Is cut off.
[0021]
In the semiconductor integrated circuit device and the wireless communication terminal of the present invention, communication using the electromagnetic induction is performed with the first communication device in close proximity via the antenna, Included in the drive circuit that operates with the power supplied from the power supply unit Of the transmission data signal representing the data to be transmitted to the first communication device, the transmission data signal whose amplitude is not inverted and the transmission carrier signal whose amplitude is not inverted are superimposed by the parasitic diode bridge circuit Then, the transmission data signal whose amplitude is inverted and the transmission carrier signal whose amplitude is inverted are superimposed, and the antenna is driven by the differential output based on each superimposed signal. Further, based on the signal supplied from the antenna and rectified in the parasitic diode bridge circuit, the data transmitted from the first communication device is detected by the detection amplifier.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a diagram showing a configuration example of a non-contact IC card reader / writer 1 to which the present invention is applied, which is constituted by a one-chip IC (Integrated Circuit).
[0023]
The non-contact IC card reader / writer 1 includes a non-contact IC card unit 11 and a reader / writer unit 12, and the operation is switched according to control by a CPU (Central Processing Unit) (not shown) or the like. In other words, depending on the situation at that time, whether to operate as a non-contact IC card or to operate as a reader / writer is appropriately switched for an external device.
[0024]
The antenna 21 has a resonance circuit composed of a loop coil 31 and a capacitor 32. As shown in FIG. 1, the antenna 21 is connected to a circuit at the subsequent stage of the non-contact IC card unit 11 and is also connected to the reader / writer unit 12.
[0025]
Therefore, the antenna 21 is driven in any period of the period in which the non-contact IC card reader / writer 1 operates as a non-contact IC card and the period in which the antenna 21 operates as a reader / writer. Of course, an antenna dedicated to the non-contact IC card unit 11 and an antenna dedicated to the reader / writer unit 12 may be provided.
[0026]
For example, when the non-contact IC card reader / writer 1 operates as a non-contact IC card, a signal radiated from an external reader / writer and received by the antenna 21 is rectified. It is supplied to the circuit 22.
[0027]
Hereinafter, a reader / writer that exists outside the non-contact IC card reader / writer 1 and reads / writes predetermined data to / from the non-contact IC card reader / writer 1 operating as a non-contact IC card will be referred to as an external reader / writer. Similarly, a non-contact IC card that exists outside the non-contact IC card reader / writer 1 and that reads and writes predetermined data by the non-contact IC card reader / writer 1 that operates as a reader / writer is referred to as an external non-contact IC card. .
[0028]
The rectifier circuit 22 includes a diode 33 and a capacitor 34, rectifies and smoothes a signal supplied from the antenna 21, and supplies a positive voltage to a regulator (not shown). In the regulator, the positive level voltage supplied from the rectifier circuit 22 is stabilized and converted to a predetermined level of DC voltage, and then used as a power source for a sequencer (not shown) and other circuits. Supplied.
[0029]
The signal rectified and smoothed by the rectifier circuit 22 is also supplied to an HPF (High Pass Filter) 24 constituted by a capacitor 37 and a resistor 38, and after the high frequency component is extracted, the signal is amplified from an amplifier circuit or a demodulator circuit. The received data acquisition unit 25 is supplied.
[0030]
The reception data acquired by the reception data acquisition unit 25 (data transmitted from the external reader / writer) is output to a sequencer, a CPU connected via an interface, and the like.
[0031]
A modulation circuit 23 is connected to the subsequent stage of the rectifier circuit 22. The modulation circuit 23 is configured by a series circuit of a resistor 35 and an FET (Field Effect Transistor) 36, and is connected in parallel with the loop coil 31 of the antenna 21. The FET 36 switches on / off based on a signal from the transmission data supply unit 26 (a signal representing data transmitted to the external reader / writer). That is, the state where the resistor 35 is inserted in parallel with the antenna 21 and the state where the resistor 35 is not inserted are switched.
[0032]
The signal output from the transmission data supply unit 26 to the modulation circuit 23 is processed by a CPU, a sequencer, or the like as data to be transmitted to the external reader / writer.
[0033]
By switching on / off of the FET 36, the impedance of the circuit that is electromagnetically coupled via the loop coil 31 (the load of the loop antenna provided in the external reader / writer) is changed and operates as a non-contact IC card. Data is transmitted from the non-contact IC card reader / writer 1 to the external reader / writer.
[0034]
The reader / writer unit 12 is a transmission carrier supply unit that supplies a transmission carrier signal having a frequency of, for example, 13.56 MHz to the antenna driving circuit 51 that drives the antenna 21 by differential output, the inverter 61 and the inverter 65 of the antenna driving circuit 51. 52, from the external non-contact IC card based on the output from the antenna drive circuit 51 and the transmission data supply unit 53 that supplies the inverter 64 and the inverter 66 with a signal representing the transmission data to be transmitted to the external non-contact IC card It is comprised from the reception data acquisition part 54 which acquires the transmitted data.
[0035]
The transmission carrier signal output from the transmission carrier supply unit 52 to the antenna drive circuit 51 is subjected to modulation processing based on the transmission data output from the transmission data supply unit 53.
[0036]
Specifically, the transmission carrier signal supplied from the transmission carrier supply unit 52 is input to the inverter 61 and the inverter 65, respectively, and the inverted signal is output from each inverter. The output signal of the inverter 61 is input to the inverter 62, inverted again, and then superimposed on the output signal of the inverter 63 at the contact a. The output signal of the inverter 65 is superimposed on the output signal of the inverter 66 at the contact b.
[0037]
On the other hand, the transmission data signal supplied from the transmission data supply unit 53 to the antenna drive circuit 51 is input to the inverter 64 and the inverter 66, respectively, and inverted signals are output from the inverters. The output signal of the inverter 64 is input to the inverter 63, inverted again, and then superimposed on the output signal of the inverter 62. The output signal of the inverter 66 is superimposed on the output signal of the inverter 65.
[0038]
Therefore, the output signal of the transmission carrier generation unit 52 (transmission carrier signal whose amplitude is not inverted) and the output signal of the transmission data supply unit 53 (transmission data signal whose amplitude is not inverted) are at the contact a. The transmission carrier signal that is superimposed (ASK (Amplitude Shift Keying) modulated) and whose amplitude is inverted is similarly superimposed on the transmission data signal whose amplitude is inverted at the contact b.
[0039]
The signals superimposed at the contacts a and b are output to the antenna 21, and the corresponding electromagnetic waves are radiated from the antenna 21.
[0040]
Thus, since the antenna 21 is driven by the differential output, it is possible to suppress the influence of noise in the transmission path.
[0041]
The reception data acquisition unit 54 acquires data output from the external non-contact IC card based on the signal supplied from the antenna drive circuit 51 and outputs it to a sequencer or the like.
[0042]
Specifically, as shown in FIG. 2, parasitic elements formed when the inverter 62, the inverter 63, the inverter 65, and the inverter 66 of the antenna drive circuit 51 are realized by a CMOS (Complementary Metal Oxide Semiconductor) IC. The output signal from the diode bridge circuit 71 is amplified and demodulated by the detection amplifier 81, and the obtained reception data is output to the reception data acquisition unit 54.
[0043]
As will be described in detail later, since a full-wave rectified signal is output from the parasitic diode bridge circuit 71, an external non-contact IC is based on a half-wave rectified signal output from a receiving circuit including a diode, a capacitor, and the like. As compared with the case of acquiring data transmitted from the card, the receiving sensitivity can be improved, and the data from the external non-contact IC card can be acquired more reliably.
[0044]
In addition, even when a circuit dedicated to reception is not formed in the chip, it is possible to acquire data output from an external contactless IC card, that is, the function as a reader / writer is built into the chip. Since it can be held, the chip area can be reduced compared to the case where a circuit dedicated to reception is provided.
[0045]
In FIG. 2, the other configurations of FIG. 1 other than the loop coil 31, the antenna drive circuit 51, the parasitic diode bridge circuit 71, and the detection amplifier 81 are omitted. For example, the transmission data supply of FIG. As shown in FIG. 3, the unit 26 is connected to the loop coil 31 in parallel with the antenna drive circuit 51 via the resistor 35 and the FET 36.
[0046]
Also, as shown in FIG. 4, a switch 91 is provided between the output side of the parasitic diode bridge circuit 71 and a power supply unit (not shown), and when operating as a reader / writer, the switch 91 is turned on, On the other hand, when operating as a non-contact IC card, power supply to the antenna drive circuit 51 can be controlled by turning off the switch 91. Further, by connecting the resistor 92 in parallel to the detection amplifier 81, it is possible to more reliably detect the load fluctuation of the external non-contact IC card.
[0047]
By providing the resistor 92 outside the antenna drive circuit 51, the resistance value of the resistor 92 can be easily changed.
[0048]
As shown in FIG. 5, a diode 91A may be connected to the antenna drive circuit 51 instead of the switch 91 in FIG. 4, and the power supply to the antenna drive circuit 51 may be controlled by its operation. . In this case, the reverse bias voltage is applied to the diode 91A by the voltage rectified and generated in the parasitic diode bridge circuit 71, and the supply of power is cut off.
[0049]
Here, the parasitic diode bridge circuit 71 formed in the antenna drive circuit 51 will be described.
[0050]
For example, when the inverter 101 shown in FIG. 6 is realized by a CMOS inverter, as shown in FIG. 7, the inverter 101 includes a P-MOS (P-channel MOS transistor) 111 and a N-channel transistor connected to each drain. This is realized by a MOS (N-channel MOS transistor) 112.
[0051]
When there is a GND level input to the CMOS of FIG. 7, the P-MOS 111 becomes conductive and the N-MOS 112 becomes non-conductive, and a VDD level signal is output. On the other hand, when the input is at the VDD level, the P-MOS 111 is non-conductive and the N-MOS 112 is conductive, and a GND level signal is output.
[0052]
FIG. 8 shows a cross section of the CMOS of FIG. 7. From the difference in the concentration of impurities contained in each region, P-MOS 111 surrounded by the alternate long and short dash line between BG-S, BG-D, and N A parasitic diode is formed between the BG-D and the BG-S of the MOS 112.
[0053]
Therefore, when a parasitic diode formed between the regions is added, the circuit shown in FIG. 7 is as shown in FIG. That is, a parasitic diode 121 having the S side as an anode is formed between BG-S of the P-MOS 111, and a parasitic diode 122 having an D side as an anode is formed between BG-D. Further, a parasitic diode 123 having the D side as a cathode is formed between BG-D of the N-MOS 112, and a parasitic diode 124 having a S side as a cathode is formed between BG-S.
[0054]
9, since BG-S of the P-MOS 111 and S-BG of the N-MOS 112 are short-circuited, when the inverter 101 of FIG. 6 is realized by CMOS, the circuit configuration is finally shown in FIG. Thus, a parasitic diode 122 having an anode on the D side is formed between the SDs of the P-MOS 111, and a parasitic diode 123 having an anode on the S side is formed between the DSs of the N-MOS 112.
[0055]
Therefore, in the antenna drive circuit 51 shown in FIG. 11, when the portions of the inverter 62, the inverter 63, the inverter 65, and the inverter 66 surrounded by the alternate long and short dash line are realized as CMOS inverters, the circuit configuration is shown in FIG. As shown in the figure, it is composed of an FET and a parasitic diode.
[0056]
11 and 12, inputs to the inverter 62 and the inverter 65 are shown as IN1 and IN2, respectively, and outputs of the inverter 62 and the inverter 65 are shown as OUT1 and OUT2, respectively.
[0057]
In FIG. 12, the transmission carrier (IN1) output from the transmission carrier supply unit 52 and inverted by the inverter 61 is input to the FET 131 and FET 132, while the transmission carrier supply unit 52 outputs to the FET 133 and FET 134. The transmitted carrier (IN2) is input.
[0058]
One end of the loop coil 31 is connected between the respective drains of the FET 131 and the FET 132, and an output signal (OUT1) is output therefrom. One end of the loop coil 31 is connected between the drains of the FET 133 and the FET 134, and an output signal (OUT2) is output therefrom.
[0059]
In FIG. 12, an FET (FET for realizing the inverter 63 and the inverter 66 in FIG. 11) to which a signal representing the transmission data supplied from the transmission data supply unit 53 is input is omitted. The FET (P-MOS, N-MOS) that realizes the inverter 63 is connected in parallel to the FET 131 and the FET 132 in FIG. 12, and the respective outputs are superimposed and a modulated signal is output to the loop coil 31. The Further, FETs (P-MOS, N-MOS) that realize the inverter 66 are connected in parallel with the FET 133 and the FET 134, and outputs of the respective signals are superimposed and a modulated signal is output to the loop coil 31.
[0060]
A parasitic diode 141 having an anode on the D side is formed between the SDs of the FETs 131 shown in FIG. 12, and a parasitic diode 142 having an anode on the S side is formed between the DSs of the FETs 132. A parasitic diode 143 having an anode on the D side is formed between the SDs of the FET 133, and a parasitic diode 144 having an anode on the S side is formed between the DSs of the FET 134.
[0061]
These parasitic diodes 141 to 144 constitute a parasitic diode bridge circuit 71.
[0062]
FIG. 13 is a diagram showing a parasitic diode bridge circuit 71 configured by the parasitic diodes 141 to 144 of FIG.
[0063]
In the parasitic diode bridge circuit 71, both ends of the loop coil 31 are connected to a point between the anode of the parasitic diode 141 and the cathode of the parasitic diode 142 and to a point b between the anode of the parasitic diode 143 and the cathode of the parasitic diode 144. The signal representing the output from the external contactless IC card received by the loop coil 31 is input to the parasitic diode bridge circuit 71.
[0064]
The signal rectified in the parasitic diode bridge circuit 71 is input to a point c between the parasitic diode 141 and the parasitic diode 143, and a full-wave rectified signal is output to the detection amplifier 81. Further, the full-wave rectified signal input to the point c is output to the outside of the antenna drive circuit 51 via the switch 91 and the resistor 92 (FIG. 4), and is also output to the series regulator 153.
[0065]
In series regulator 153, the resistance value of the variable element provided therein is controlled and stabilized based on the difference between the output voltage from antenna drive circuit 51 (parasitic diode bridge circuit 71) and a predetermined reference voltage. A predetermined voltage is output. The output voltage from the series regulator 153 is appropriately supplied to each part of the non-contact IC card reader / writer 1.
[0066]
FIG. 14 shows an example of a signal input between ab in FIG. 13, and an AC signal as shown in the figure is received by the antenna 21 and input to the parasitic diode bridge circuit 71.
[0067]
FIG. 15 is a diagram showing an output signal of the parasitic diode bridge circuit 71 when the signal shown in FIG. 14 is input between ab in FIG. 13, and at the contact c in FIG. 13, as shown in FIG. A smoothed full wave rectified signal is detected.
[0068]
Therefore, when a full-wave rectified signal as shown in FIG. 14 is input, the detection amplifier 81 acquires, for example, data “0” and “1” as shown in FIG.
[0069]
As described above, the parasitic diode bridge 71 formed when the antenna drive circuit 51 which is the transmission circuit of the reader / writer unit 12 is realized by CMOS is also used as the reception circuit, and based on the full-wave rectified signal which is the output thereof. Since the data output from the external non-contact IC card is acquired, the chip area can be reduced and the receiving sensitivity can be improved. That is, erroneous detection of data can be suppressed.
[0070]
The non-contact IC card reader / writer 1 having the above-described configuration is not limited to various information processing apparatuses that transmit / receive information to / from external devices such as personal computers, PDAs (Personal Digital Assistants), mobile phones, and digital cameras. It is also disposed on a predetermined medium such as a card or paper.
[0071]
FIG. 17 is a block diagram showing a configuration example of a mobile phone provided with the non-contact IC card reader / writer 1 of FIG.
[0072]
The CPU 208 develops a control program stored in a ROM (Read Only Memory) 209 in a RAM (Random Access Memory) 210, and controls the overall operation of the mobile phone according to the control program.
[0073]
For example, the CPU 208 controls a DSP (Digital Signal Processor) 204 based on an instruction from the user, transmits and receives various types of information such as voice information to and from the base station, and also uses the contactless IC card reader / writer 1. Control and perform short-range wireless communication using electromagnetic induction with devices such as contactless IC cards that are in close proximity.
[0074]
In the transmission unit 202 and the reception unit 203, for example, communication conforming to a PDC (Personal Digital Cellular) method or a W-CDMA (Wideband-Code Division Multiple Access) method is performed.
[0075]
When audio information is supplied from the DSP 204, the transmission unit 202 performs predetermined processing such as digital-analog conversion processing and frequency conversion processing, and uses the obtained audio signal as a predetermined transmission carrier selected by the base station. It transmits from the antenna 201 by the radio channel of a frequency.
[0076]
For example, in the voice call mode, the reception unit 203 amplifies the RF signal received by the antenna 201 and performs predetermined processing such as frequency conversion processing and analog-digital conversion processing, and outputs the obtained voice information to the DSP 204. To do.
[0077]
The DSP 204 performs, for example, spectrum despreading processing on the audio information supplied from the reception unit 203, and outputs the obtained data to the audio processing unit 205. Further, the DSP 204 performs spread spectrum processing on the audio information supplied from the audio processing unit 205 and outputs the obtained data to the transmission unit 202.
[0078]
The voice processing unit 205 converts the user's voice collected by the microphone 207 into voice information and outputs it to the DSP 204. The audio processing unit 205 converts the audio information supplied from the DSP 204 into an analog audio signal and outputs a corresponding audio signal from the speaker 206.
[0079]
The display unit 211 is configured by an LCD (Liquid Crystal Display) or the like, and displays a corresponding screen based on information supplied from the CPU 208. The input unit 212 detects user input to various buttons such as a numeric keypad, a call button, and a power button provided on the surface of the mobile phone casing, and outputs corresponding signals to the CPU 208.
[0080]
In the non-contact IC card reader / writer 1 provided in the mobile phone having the above configuration, as described above, the parasitic diode bridge circuit formed when the antenna driving circuit is realized by CMOS is used as the receiving circuit. Then, output data from the external non-contact IC card is acquired based on the output of the parasitic diode bridge circuit. The data acquired by the non-contact IC card reader / writer 1 is appropriately output to the CPU 208 and subjected to various processes.
[0081]
【The invention's effect】
According to the present invention, an output from an external device can be acquired even when a circuit dedicated to reception is not provided.
[0082]
Moreover, according to the present invention, it is possible to improve reception sensitivity.
[0083]
Furthermore, according to the present invention, the chip area can be reduced.
[Brief description of the drawings]
FIG. 1 is a circuit diagram of a non-contact IC card reader / writer to which the present invention is applied.
FIG. 2 is a diagram showing a configuration example of a non-contact IC card reader / writer to which the present invention is applied.
FIG. 3 is a diagram showing another configuration example of a non-contact IC card reader / writer to which the present invention is applied.
FIG. 4 is a diagram showing still another configuration example of a non-contact IC card reader / writer to which the present invention is applied.
FIG. 5 is a diagram showing a configuration example of a non-contact IC card reader / writer to which the present invention is applied.
FIG. 6 is a diagram showing an inverter.
7 is a circuit diagram when the inverter of FIG. 6 is realized by CMOS.
8 is a view showing a cross section of the FET of FIG. 7;
9 is a diagram showing a modification of the circuit of FIG.
10 is a diagram showing a modification of the circuit of FIG.
FIG. 11 is a diagram showing the antenna drive circuit of FIG. 1;
12 is a circuit diagram when the inverter of FIG. 11 is realized by CMOS.
13 is a diagram showing a modification of the circuit of FIG.
14 is a diagram illustrating an example of a signal detected in the circuit of FIG. 13;
15 is a diagram showing another example of a signal detected in the circuit of FIG.
16 is a diagram showing still another example of a signal detected in the circuit of FIG.
FIG. 17 is a block diagram illustrating a configuration example of a mobile phone to which the present invention is applied.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Non-contact IC card reader / writer, 11 Non-contact IC card part, 12 Reader / writer part, 51 Antenna drive circuit, 71 Parasitic diode bridge circuit

Claims (10)

A first communication device in close proximity, an antenna that performs communication using electromagnetic induction,
A drive circuit including a parasitic diode bridge circuit that is operated by power supplied from a power supply unit , wherein the amplitude of a transmission data signal representing data transmitted to the first communication device by the parasitic diode bridge circuit The transmission data signal whose polarity is not inverted and the transmission carrier signal whose amplitude is not inverted are superimposed on each other, the transmission data signal whose amplitude is inverted, and the transmission whose amplitude is inverted and a carrier signal is superimposed, the differential output based on each of the superimposed signal, and the driving circuit for driving the antenna,
A semiconductor integrated circuit device comprising: a detection amplifier that detects data transmitted from the first communication device based on a signal supplied from the antenna and rectified in the parasitic diode bridge circuit. The semiconductor integrated circuit device according to claim 1, wherein a resistor is disposed between the parasitic diode bridge circuit and the power supply unit that supplies power to the drive circuit. When receiving an electromagnetic wave radiated from a second communication device that is close to the antenna, the load of the antenna is controlled based on predetermined data transmitted to the second communication device and received by the antenna. The semiconductor integrated circuit device according to claim 1, further comprising a modulation circuit that modulates the electromagnetic wave. A switch for controlling power supply to the drive circuit is further provided between the parasitic diode bridge circuit and the power supply unit;
The semiconductor integrated circuit device according to claim 3, wherein the power supply is cut off by the switch during a period in which the predetermined data is transmitted to and received from the second communication device. A diode for controlling the supply of power to the drive circuit is further provided between the parasitic diode bridge circuit and the power supply unit;
The diode is reverse-biased by a voltage generated by rectifying electromagnetic waves radiated from the second communication device and received by the antenna in the parasitic diode bridge circuit formed in the drive circuit, The semiconductor integrated circuit device according to claim 3, wherein supply of power is cut off. A first communication device in close proximity, an antenna that performs communication using electromagnetic induction,
A drive circuit including a parasitic diode bridge circuit that is operated by power supplied from a power supply unit , wherein the amplitude of a transmission data signal representing data transmitted to the first communication device by the parasitic diode bridge circuit The transmission data signal whose polarity is not inverted and the transmission carrier signal whose amplitude is not inverted are superimposed on each other, the transmission data signal whose amplitude is inverted, and the transmission whose amplitude is inverted and a carrier signal is superimposed, the differential output based on each of the superimposed signal, and the driving circuit for driving the antenna,
A wireless communication terminal comprising: a detection amplifier that detects data transmitted from the first communication device based on a signal supplied from the antenna and rectified in the raw diode bridge circuit. The wireless communication terminal according to claim 6, wherein a resistor is disposed between the parasitic diode bridge circuit and the power supply unit that supplies power to the drive circuit. When receiving an electromagnetic wave radiated from a second communication device that is close to the antenna, the load of the antenna is controlled based on predetermined data transmitted to the second communication device and received by the antenna. The wireless communication terminal according to claim 6, further comprising a modulation circuit that modulates the electromagnetic wave. A switch for controlling power supply to the drive circuit is further provided between the parasitic diode bridge circuit and the power supply unit;
The wireless communication terminal according to claim 8, wherein the power supply is cut off by the switch during a period in which the predetermined data is transmitted to and received from the second communication device. A diode for controlling the supply of power to the drive circuit is further provided between the parasitic diode bridge circuit and the power supply unit;
The diode is reverse-biased by a voltage generated by rectifying electromagnetic waves radiated from the second communication device and received by the antenna in the parasitic diode bridge circuit formed in the drive circuit, The wireless communication terminal according to claim 8, wherein power supply is interrupted.

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