JP2016143339A - Radio communication device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio communication device preventing the performance of a detection circuit from lowering even when the intensity of the reception electric wave becomes high and the internal voltage is suppressed and capable of performing a highly accurate data communication.SOLUTION: An IC tag includes: a rectifying circuit (11) for rectifying the reception electric wave so as to be converted into a direct current; an internal power supply circuit (13) for generating the power supply voltage of the internal circuit based on the voltage converted by the rectifying circuit; and a detection circuit (15) for restoring information signal components by detecting the reception signal adjusted in amplitude. The internal power supply circuit includes: a protection function for limiting the voltage applied to the internal circuit and protecting the circuit; and a voltage response function for controlling the voltage generated according to the magnitude of the input voltage, and is operable in either a first operation mode operating in a state in which the protection function and the voltage response function are operated or a second operation mode operating in a state in which the protection function only is operated. The transition control from the first operation mode to the second operation mode is performed based on the output of the detection circuit.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a wireless communication device such as a passive IC tag with a built-in detection circuit, and further to an internal power supply circuit of the wireless communication device. For example, the wireless communication device is suitable for an environment information collection system that collects environment information of a measurement target. Related to communication devices.

  Passive IC tags and non-contact IC cards have an internal power supply circuit that converts received radio waves into alternating current and rectifies them to generate an internal power supply. As described above, in passive IC tags and non-contact IC cards that operate by external power supply, the received voltage is too high, that is, if the supplied power is too high, the internal voltage rises and forms an internal circuit. There is a possibility that the element is destroyed. Therefore, a shunt regulator is used as an internal power supply circuit, and an internal voltage generated even when excessive power is supplied from the outside is suppressed to protect the internal circuit (see, for example, Patent Document 1). .

JP-A-11-250211

  However, in a passive IC tag incorporating a circuit for performing communication (command and data transmission / reception) with a tag reader using an amplitude modulation (ASK) method and a shunt regulator as an internal power supply circuit, the intensity of received radio waves Is high (for example, when the distance between the tag reader and the IC tag is short), the level of the internal voltage is suppressed by the regulator characteristics. At this time, since the amplitude of the signal to be detected is also suppressed, it acts to reduce the difference between the amplitude corresponding to “1” and the amplitude corresponding to “0” of the amplitude-modulated received signal. As a result, it has been clarified that there is a problem that the reliability (detection characteristics) of signal waveform detection is lowered and the accuracy of data communication is lowered despite the good communication environment (good SN ratio).

  The present invention has been made paying attention to the above-mentioned problems, and prevents the characteristics of the detection circuit from deteriorating even when the intensity of the received radio wave is increased and the internal voltage is suppressed. An object of the present invention is to provide a wireless communication device that can be used.

In order to achieve the above object, the invention of the present application is
A rectifying circuit that rectifies a received radio wave to convert it into a direct current, an internal power supply circuit that generates a power supply voltage of the internal circuit based on the voltage converted by the rectifying circuit, and an information obtained by detecting the amplitude-modulated received signal In a wireless communication device including a detection circuit that restores a signal component,
The internal power circuit is
A protective function for protecting the circuit by limiting the voltage applied to the internal circuit, and a voltage response function for controlling the voltage generated according to the magnitude of the input voltage,
It is possible to operate in either the first operation mode in which the protection function and the voltage response function are activated or the second operation mode in which the protection function is activated, and from the first operation mode The shift control to the second operation mode is performed based on the output of the detection circuit.

  According to the invention having the above-described configuration, the information signal included in the carrier wave modulated by the amplitude modulation method while protecting the internal circuit by limiting the voltage applied to the internal circuit according to the received radio wave intensity originally received by the carrier wave It can be avoided that the component (amplitude difference) is crushed by the regulator characteristics and the detection accuracy is lowered, and even if the internal voltage is suppressed by increasing the intensity of the received radio wave, the characteristics of the detection circuit are reduced. Therefore, highly accurate data communication can be performed between the wireless communication device (IC tag) and the tag reader.

Preferably, the internal power supply circuit controls a voltage control element provided in parallel with the internal circuit and a resistance value of the voltage control element so that a voltage applied to the internal circuit becomes a predetermined potential. A shunt regulator with a control circuit
Volatile storage means capable of storing the output voltage of the control circuit applied to the control terminal of the voltage control element, and an analog switch provided between the output terminal of the control circuit and the control terminal of the voltage control element And the analog switch can be turned on and off based on the output of the detection circuit,
When the analog switch is turned off, the output voltage of the control circuit is stored in the volatile storage means, the voltage response function is stopped, and the transition from the first operation mode to the second operation mode is performed. Configure as follows.

  According to such a configuration, the protection function and the voltage response function can be obtained only by adding a volatile memory means and an analog switch to the conventional circuit and providing a signal line for connecting the output terminal of the detection circuit and the control terminal of the analog switch. It is possible to perform transition control from the first operation mode that operates in the activated state to the second operation mode that operates in the state in which the protection function is activated, and thereby, the information signal included in the carrier wave modulated by the amplitude modulation method It can be easily avoided that the component (amplitude difference) is crushed by the regulator characteristic and the detection accuracy is lowered.

Further preferably, the control circuit is configured to divide an input voltage or a voltage applied to the internal circuit, and an error in which a voltage divided by the voltage dividing circuit and a predetermined constant voltage are input. And an amplifier.
By configuring the control circuit for controlling the resistance value of the voltage control element from the voltage dividing circuit and the error amplifier, it is possible to limit the voltage applied to the internal circuit to a certain value or less. It is possible to more reliably avoid the rising and destruction of the elements constituting the internal circuit.

Desirably, the volatile memory means is a capacitive element connected between a control terminal of the voltage control element and a reference potential point.
As a result, the circuit can be simplified.

Furthermore, preferably, it comprises non-volatile storage means capable of storing its own identification code, and a transmission circuit for transmitting data,
When the command code requesting data transmission is restored by the detection of the detection circuit, the identification code stored in the nonvolatile storage means is transmitted by the transmission circuit.
According to this configuration, it is possible to obtain a wireless communication device suitable for an environment information collection system that collects environment information.

Preferably, the identification code stored in the non-volatile storage means is provided when a command code for requesting data transmission is restored by detection of the detection circuit, the temperature measurement means being capable of measuring temperature. And the measurement data measured by the said temperature measurement means are comprised so that it may transmit by the said transmission circuit.
Thereby, it becomes possible to easily collect and manage measurement data collected from a plurality of wireless communication devices.

  According to the present invention, in a passive wireless communication device with a built-in detection circuit, even if the intensity of received radio waves is increased and the internal voltage is suppressed, the characteristics of the detection circuit are prevented from deteriorating, and high-precision data There is an effect that communication can be performed.

1 is a functional block diagram of a first embodiment of a passive wireless communication device (IC tag) according to the present invention. It is a figure which shows the relationship between the characteristic of a regulator in the conventional IC tag and the IC tag of this embodiment, and a detection waveform. It is a functional block diagram of 2nd Embodiment of the passive type IC tag which concerns on this invention. It is a schematic block diagram which shows the structure at the time of applying an IC tag to the environmental information supplement collection system of a railway line. FIG. 5 is a functional block diagram showing a configuration example of an IC tag suitable for use in the environment information collection system of FIG. 4.

Hereinafter, embodiments of a wireless communication device according to the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a block diagram showing an embodiment in which a wireless communication device according to the present invention is applied to a passive IC tag.
As shown in FIG. 1, the passive IC tag 10 of this embodiment includes a rectifier circuit 12 that rectifies radio waves (AC waveform) received from a coil 11 serving as an antenna and converts the radio waves into DC, and a rectifier circuit 12 converts the radio wave. The shunt regulator 13 as an internal power supply circuit that generates the power supply voltage of the circuit inside the tag chip based on the voltage (DC voltage), the power supply line VDD to which the power supply voltage generated by the shunt regulator 13 is supplied, and the reference potential A load 14 connected between a ground line GND to be applied and a detection circuit 15 as a reception circuit for detecting an amplitude-modulated reception signal and restoring an information signal component.

The load 14 is included in an internal circuit of the IC tag 10, and the internal circuit includes a circuit that recognizes a command and controls the inside of the chip, an oscillation circuit, and a transmission circuit that transmits data to the outside. The detection circuit 15 can also be regarded as an internal circuit, that is, a load of the regulator 13. When the IC tag of the present embodiment is an IC tag suitable for an environment information collection system that collects environment information described later, a measurement circuit that measures a physical quantity such as temperature is also an internal circuit.
As the transmission circuit, for example, by changing the reflection coefficient (impedance) of the antenna according to the selected transmission data, the characteristic of the carrier wave from the tag reader is changed so that the tag reader can discriminate the data. Can be used. Note that a load modulation type transmission circuit can be realized by a circuit technique (for example, Japanese Patent Application Laid-Open No. 2009-302615) used in a conventional non-contact IC card, and thus detailed description thereof is omitted.

  As shown in FIG. 1, the shunt regulator 13 includes a control element (hereinafter referred to as a voltage transistor) such as a MOS transistor (insulated gate field effect transistor) connected in parallel with the load 14 between the power line VDD and the ground line GND. Control transistor) 31, a voltage dividing resistor R1, R2 that is connected in series between the power supply line VDD and the ground line GND and forms a voltage dividing circuit that divides the voltage of the power supply line, and the voltage dividing resistors R1, R2 And an error amplifier (error amplifier) 32 that outputs a voltage corresponding to the potential difference between the voltage divided by the predetermined constant voltage Vbias1, and the output voltage of the error amplifier 32 is the gate terminal of the voltage control transistor 31. Is applied to the power supply line VDD so that the voltage of the power supply line VDD becomes constant. The constant voltage Vbias1 applied to one input terminal of the error amplifier 32 is generated by a reference voltage generation circuit (not shown).

Since the shunt regulator 13 supplies the voltage from the rectifier circuit 12 to the load as it is when the voltage from the rectifier circuit 12 is equal to or lower than a predetermined potential, the received radio wave intensity is as shown by a solid line A in FIG. Until the voltage reaches a predetermined level, the voltage of the power supply line VDD increases in proportion to the received radio wave intensity. When the received radio wave intensity becomes higher than a predetermined level, the voltage of the power line VDD is maintained at a predetermined potential, that is, constant. Performs voltage control operation.
The voltage VDD of the power supply line divided by the voltage dividing resistors R1 and R2 constituting the voltage dividing circuit is a voltage applied to an internal circuit as the load 14 in terms of circuit, but is an input voltage of the shunt regulator 13. is there. Therefore, the shunt regulator 13 as the internal power supply circuit has a protection function for protecting the circuit by limiting the voltage applied to the internal circuit, and a voltage response function for controlling the voltage generated according to the magnitude of the input voltage. It will be provided.

Further, in the passive IC tag 10 of the present embodiment, the capacitive element 33 is connected between the gate terminal of the voltage control transistor 31 and the ground line GND for supplying a reference potential, and the output of the error amplifier 32 is also provided. An analog switch 34 is provided between the terminal and the gate terminal of the voltage control transistor 31, and the switch 34 is configured to be turned on / off by a signal from the detection circuit 15.
Specifically, the switch 34 is turned on while the output signal of the detection circuit 15 is at the low level, and the switch 34 is turned off when the output signal changes from the low level to the high level, and the output voltage Vx of the error amplifier 32 before the change is stored in the capacitor. It is configured to store in the element 33. Accordingly, the capacitive element 33 functions as an analog memory that stores the output voltage Vx of the error amplifier 32.
The capacitance value of the capacitive element 33 is desirably about 0.5 p to several pF. This is because when the capacitance value of the capacitive element 33 is small, the voltage held in the capacitive element 33 is reduced due to leakage, whereas when the capacitance value is large, the regulator response to changes in the input voltage is delayed.

  Note that the shunt regulator 13 uses an N-channel MOS transistor as shown in FIG. 1B, as compared with the one shown in FIG. 1A, which uses a P-channel MOS transistor as the voltage control transistor 31. Thus, the input (+, −) of the error amplifier 32 may be reversed. The analog switch 34 can be constituted by a so-called CMOS transmission gate formed by connecting one MOS transistor (P-channel MOS transistor) or a P-channel MOS transistor and an N-channel MOS transistor in parallel. .

  Next, the operation of the shunt regulator 13 in the passive IC tag 10 of the present embodiment will be described using FIG. 2 while comparing with the operation of a conventional shunt regulator without the capacitive element 33 and the switch 34. 2A shows the characteristics of the regulator and the change of the output waveform of the detection circuit in the IC tag using the conventional shunt regulator, and FIG. 2B shows the regulator in the IC tag using the shunt regulator of this embodiment. (A) shows the output of the detection circuit when VDD is relatively low, such as b point of the regulator characteristic, and (b) shows the b point of VDD where the regulator characteristic is the regulator characteristic. (C) is a detection circuit in the case where the voltage control transistor 31 is strongly turned on and suppressed to a predetermined voltage as shown by the point c of the regulator characteristics. The output waveform of is shown.

In an IC tag using a conventional shunt regulator, when the reception strength, that is, the amplitude of the voltage from the rectifier circuit 12 increases, VDD is suppressed by the characteristics of the shunt regulator, that is, the voltage control transistor 31 is controlled by the output voltage of the error amplifier 32. As shown in the waveform (c) of FIG. 2 (A), the output of the detection circuit has a waveform like a sawtooth wave that once rises and then gradually decreases.
On the other hand, in the IC tag using the shunt regulator of this embodiment, even if the reception intensity, that is, the amplitude of the voltage from the rectifier circuit 12 is increased, the switch 34 is turned off and the amplitude changes with the information signal component of AM modulation. The output voltage of the error amplifier 32 before the storage is stored in the capacitive element 33. Therefore, the on-resistance value of the voltage control transistor 31 does not change, that is, the shunt regulator is insensitive to the information signal component included in the carrier wave, and as shown in the waveform (c) of FIG. The output does not decrease after increasing, but becomes a desired rectangular waveform. As a result, it is possible to prevent the restored waveform from being collapsed due to the strength of the received radio wave being too high and the data communication accuracy from being lowered.

The function of the shunt regulator is to protect the load by limiting the voltage applied to the load by letting a part of the current flowing toward the load escape through a variable resistor provided in parallel with the load. By changing the resistance value of the variable resistor according to the magnitude of the voltage, it can be divided into a voltage response function that makes the voltage applied to the load constant. The regulator according to the present embodiment is a fixed resistor having the immediately preceding resistance value by temporarily stopping the first operation mode in which both functions are activated and the voltage response function of the latter. And the second operation mode in which only the former protection function is activated, and the transition control from the first operation mode to the second operation mode is performed by the output of the detection circuit. It can be said that it is a circuit.
As a result, the information signal component (amplitude difference) contained in the carrier wave modulated by the amplitude modulation method while protecting the load by limiting the voltage applied to the load (internal circuit) according to the received radio wave intensity inherent in the carrier wave. Can be prevented from being crushed by the regulator characteristics and deteriorating the detection accuracy.

(Second Embodiment)
Next, a second embodiment of the passive IC tag according to the present invention will be described with reference to FIG. In the second embodiment, a clamp circuit 35 is used instead of the error amplifier 32 in the shunt regulator of FIG. FIG. 3A is a circuit diagram of the shunt regulator 13 of the second embodiment, and FIG. 3B is a diagram showing the clamp circuit 35 of the shunt regulator 13 as an equivalent circuit.
Specifically, as shown in FIG. 3, so-called diode-connected three MOS transistors Q1 to Q3 each having a gate and a drain coupled between a power supply line VDD and a ground line GND, and a predetermined gate terminal. A clamp circuit 35 is provided in which a MOS transistor Q4 to which the constant voltage Vbias2 is applied is connected in series. Of the four MOS transistors Q1 to Q4, Q1 is a P-channel type and Q2 to Q4 are N-channel types.

In this embodiment, a diode-connected MOS transistor Q5 is connected between the voltage control transistor 31 and the power supply line VDD.
A capacitive element 33 functioning as an analog memory is connected between the gate terminal of the voltage control transistor 31 and the ground line GND, and a voltage is applied to the connection node N1 of the MOS transistors Q2 and Q3 constituting the clamp circuit 35. An analog switch 34 is provided between the gate terminal of the control transistor 31 and the switch 34 is turned on / off by a signal from the detection circuit 15.

In the shunt regulator 13 of this embodiment, when an overvoltage is applied to the power supply line VDD, a current starts to flow beyond the barrier voltage of the vertically stacked MOS transistors Q1 to Q4 (diodes), and the voltage Vx at the node N1 increases. By using this as a control voltage and controlling the control transistor 31 between VDD and GND, the voltage of the power supply line VDD can be suppressed when the received radio wave intensity becomes high. Also in this embodiment, if the switch 34 connected to the node N1 is turned off, the potential of the power supply line VDD is maintained at the previous value. Therefore, as in the first embodiment, when the switch 34 is turned off by a signal from the detection circuit 15 and the voltage Vx of the node N1 is stored in the capacitive element 33 as an analog memory, the on-resistance value of the control transistor 31 is increased. It can be prevented that the information signal component (amplitude difference) included in the amplitude-modulated carrier wave is crushed and the information signal component can be extracted without being clamped.
Also in this embodiment, as the control transistor 31, either an N channel type or a P channel type MOS transistor can be used.

Next, an application example of the IC tag of the above embodiment will be described. FIG. 4 shows a system configuration when an IC tag is used as an IC tag suitable for an environment information collecting system that collects environment information.
The environmental information collection system shown in FIG. 4 is used to manage the temperature of power transmission lines and distribution lines in the power system (for example, temperature management of connection points of distribution lines and distribution lines), and supply lines for supplying power to train lines. It is used to perform temperature management (for example, temperature management of connection points by crimping sleeves of feeders).

  In the environmental information collection system of FIG. 4, the train line 40 includes a feeder 41, a trolley line 42, an auxiliary suspension line 43, a suspension line 44, a hanger 45 that connects the trolley line 42 and the auxiliary suspension line 43, a feeder 41 and an auxiliary line. A feeder branch 47a for connecting the suspension wire 43 is provided, and the suspension wire 44 is fixed to a utility pole (not shown) at a support point 44a. One end of the feeder branch portion 47a is fixed to the feeder wire 41 by an attachment device 48a, and the other end of the feeder branch portion 47a is fixed to the auxiliary suspension wire 43 by an attachment device 48b.

Then, the IC tag 10 as an environmental information measuring device having a temperature sensor for measuring the temperature as environmental information to be collected is mounted on the attachment device 48a of the feeder branch portion 47a of the feeder 41. Further, the IC tag 10 is attached to a connection point of the feeder 41, for example, a connection location (crimp sleeve 41a) using a crimp sleeve. By mounting in this way, the IC tag 10 can be provided so as to be thermally coupled to an electric wire that is a temperature measurement target.
A tag reader that receives information on the temperature measured by the IC tag 10 is mounted on the vehicle, and is transmitted along the train line by transmitting a carrier wave on which a command code for requesting measurement data is superimposed from the tag reader to the IC tag 10. The measurement data is collected by receiving signals sequentially sent from the IC tags 10.

The attachment device 48a of the feeder branch section 47a and the connection location (crimp sleeve 41a) of the feeder 41 have contact resistance, and the current passes constantly or discontinuously, so Heat is generated. In addition, even if the temperature rise due to the heat generation is not severe, if the temperature continues for a long time, the electrical resistance increases due to corrosion and fatigue. There is.
However, as described above, the IC tag 10 is provided at the feeder branch portion 47a and the connection portion 41a of the feeder 41, and the temperature rise at the attachment 48a of the feeder branch portion 47a and the connection portion 41a of the feeder 41 is achieved. By monitoring this, it is possible to detect a sign of occurrence of disconnection.

FIG. 5 shows a configuration example of an IC tag suitable for use in the environment information collection system of FIG. As shown in FIG. 5, the IC tag 10 used in this system includes a coil 11 as an antenna, a rectifier circuit 12, a shunt regulator 13 as an internal power supply circuit, and a received signal to detect an information signal component. In addition to the detection circuit 15 as a receiving circuit to be restored, a control circuit 16, a measuring unit (sensor) 17 for measuring a physical quantity as environmental information such as temperature, and a memory as a storage means for storing its own identification code and the like 18, an oscillation circuit 19 that generates an oscillation signal or a clock signal having a predetermined frequency, and a transmission circuit 20 that outputs data to the outside via the coil 11.
When the coil 11 receives the radio wave from the tag reader, the detection circuit 15 detects and restores the command code requesting the measurement data, the control circuit 16 detects the measurement data such as the temperature measured by the measurement unit (sensor) 17 and The identification code read from the memory 18 is sequentially transmitted by the transmission circuit 20.

  Although the invention made by the present inventor has been specifically described based on the embodiment, the present invention is not limited to the embodiment. For example, in the above embodiment, the analog switch 34 is directly controlled to be turned on / off based on the output of the detection circuit 15, but a latch circuit that performs a latch operation at the rising edge of the output of the detection circuit 15 is provided. The latch circuit continuously turns off the analog switch 34 during a period until a series of processing ends (one sequence period) or a period required to receive a predetermined amount of data (one frame period). May be.

  Further, in the above embodiment, the present invention is applied to the environmental information collecting system along the railway line. However, the present invention is not limited to the conventional general railway line, but along the expressway or the exclusive bus line. In addition to the environmental information collection system, the radio field intensity received by the IC tag changes in a short time, such as the collection of environmental information along the Shinkansen (including linear), and the received radio field intensity varies for each IC tag. It is effective when applied to a system in which As such a system, for example, in a collection / distribution center or a distribution center, a conveyor system that reads data from an IC tag that is affixed to a package to be delivered and stores information such as an address of a delivery destination is considered.

  Baggage handled by the conveyor system varies in size, and the distance between the tag reader and the IC tag affixed to the baggage transported by the conveyor varies from baggage to baggage, resulting in a large difference in the intensity of radio waves reaching the IC tag. As expected, when the transmission radio wave intensity of the tag reader is increased so that the IC tag data of a small package can be read, the intensity of the radio wave received on the IC tag side may become too high. Therefore, it is effective to use the IC tag according to the embodiment described above that does not deteriorate the characteristics of the detection circuit even if the received radio wave intensity is increased and the internal voltage is suppressed.

Although the invention made by the present inventor has been specifically described based on the embodiment, the present invention is not limited to the embodiment. For example, in the above embodiment, a coil is used for the antenna, but the present invention is not limited to the coil, and a dipole, a patch antenna, or the like may be used.
In addition, the present invention is not limited to an IC tag that transmits and receives data by a simple amplitude modulation method, and data is obtained by another modulation method that involves amplitude change, for example, a modulation method (QAM) that combines amplitude shift and phase shift. The present invention can also be applied to an IC tag that transmits and receives.
Furthermore, the present invention can be used not only for passive IC tags but also for non-contact IC cards. It can also be used for RFID that transmits only ID information (self-identification code). Therefore, the “wireless communication device” in the claims is a concept including not only an IC tag but also a contactless IC card and an RFID.

10 IC tag 11 Coil (antenna)
12 Rectifier circuit 13 Internal power supply circuit (shunt regulator)
14 Load (internal circuit)
DESCRIPTION OF SYMBOLS 15 Detection circuit 16 Control circuit 20 Transmission circuit 31 Voltage control transistor 32 Error amplifier (error amplifier)
33 Capacitance element (analog memory)
34 Analog switch 35 Clamp circuit

Claims (6)

A rectifying circuit that rectifies a received radio wave to convert it into a direct current, an internal power supply circuit that generates a power supply voltage of the internal circuit based on the voltage converted by the rectifying circuit, and an information obtained by detecting the amplitude-modulated received signal A wireless communication device including a detection circuit that restores a signal component,
The internal power circuit is
A protective function for protecting the circuit by limiting the voltage applied to the internal circuit, and a voltage response function for controlling the voltage generated according to the magnitude of the input voltage,
It is possible to operate in either the first operation mode in which the protection function and the voltage response function are activated or the second operation mode in which the protection function is activated, and from the first operation mode A wireless communication device configured to perform transition control to the second operation mode based on an output of the detection circuit. The internal power supply circuit includes: a voltage control element provided in parallel with the internal circuit; and a control circuit that controls a resistance value of the voltage control element so that a voltage applied to the internal circuit becomes a predetermined potential. A shunt regulator with
Volatile storage means capable of storing the output voltage of the control circuit applied to the control terminal of the voltage control element, and an analog switch provided between the output terminal of the control circuit and the control terminal of the voltage control element And the analog switch can be turned on and off based on the output of the detection circuit,
When the analog switch is turned off, the output voltage of the control circuit is stored in the volatile storage means, the voltage response function is stopped, and the transition from the first operation mode to the second operation mode is performed. The wireless communication device according to claim 1.   The control circuit includes a voltage dividing circuit that divides an input voltage or a voltage applied to the internal circuit, and an error amplifier that inputs a voltage divided by the voltage dividing circuit and a predetermined constant voltage. The wireless communication device according to claim 2.   The wireless communication device according to claim 2, wherein the volatile storage unit is a capacitive element connected between a control terminal of the voltage control element and a reference potential point. Non-volatile storage means capable of storing its own identification code, and a transmission circuit for transmitting data,
When the command code for requesting data transmission is restored by detection of the detection circuit, the identification code stored in the nonvolatile storage means is transmitted by the transmission circuit. The wireless communication device according to claim 1.   A temperature measuring unit capable of measuring temperature, and when a command code for requesting data transmission is restored by detection of the detection circuit, the identification code stored in the nonvolatile storage unit and the temperature measuring unit The wireless communication device according to claim 5, wherein the measurement data measured by the transmission circuit is transmitted by the transmission circuit.

Images