JP2004229126A - Radio transmitter/receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To acquire larger power supply from a radio power wave in a radio transmitter/receiver. <P>SOLUTION: A power supply circuit 22 comprises a smoothing circuit 24 for smoothing the burst of prescribed period included in a received signal and generating a pulse-like signal of that period, a booster circuit 26 including a transformer for boosting the pulse-like signal, and a capacitor 38 for storing the power of the signal boosted by the booster circuit 26, and uses the power stored in the capacitor 38 as at least part of the power of the power supply of a transmission processing part. In this way, possibility that the transmission processing part can be driven becomes higher by storing the power in the capacitor and using it as the power supply even in a situation that only comparatively weak radio power waves can be received. That is, a communicable area (response-possible area) of the radio transmitter/receiver is further extended. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a wireless transmission / reception device, and more particularly, to a wireless transmission / reception device receiving power supply by a wireless power wave.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, some relatively small wireless transmission / reception devices such as a non-contact IC card and an RF-ID (Radio Frequency IDentification) device receive power supply energy by a wireless power wave (for example, Patent Document 1). It is necessary to pay attention to the battery life (that is, battery capacity, replacement time, etc.) in the type with a built-in power supply battery. However, in the case of a device using a power wave, it is possible to respond only at any time when the power wave is supplied. This is advantageous in terms of energy saving because it can be performed, and also has the advantage that the labor for battery replacement can be reduced.
[0003]
[Patent Document 1]
JP-A-2002-157562
[Problems to be solved by the invention]
However, since the power energy loss amount of the wireless power wave increases as the propagation distance increases, sufficient power to drive the device cannot be obtained at a point apart from the transmission source of the power wave by a predetermined distance or more. Can not work. In particular, if the transmission power cannot be increased so much due to restrictions on the device configuration of the transmission source (for example, size and weight restrictions), the usable range is eventually limited to a narrow area.
[0005]
[Means for Solving the Problems]
A radio transmitting / receiving apparatus according to the present invention includes: a transmission processing unit that performs a predetermined process including at least modulation for transmitting a transmission signal; and a pulse-shaped signal having a predetermined period by smoothing a burst having a predetermined period included in the received signal. A booster circuit that includes a transformer that boosts the pulse-like signal; and a capacitor that stores the power of the signal boosted by the booster circuit. The power is used as the power of the transmission processing unit.
[0006]
Further, the wireless transmitting and receiving apparatus according to the present invention performs a predetermined processing including at least modulation for transmitting a transmission signal, and smoothes a burst of a predetermined cycle included in a predetermined frequency band of the reception signal. A smoothing circuit for generating a pulse-shaped signal of the cycle, a booster circuit including a switching element that is turned on / off by the pulse-shaped signal, and a transformer that is provided in series with the switching element and boosts the reception signal; And a capacitor for storing the power of the signal boosted by the booster circuit, wherein the power stored in the capacitor is used as power supply power of the transmission processing unit.
[0007]
According to the above configuration, the received power of the wireless power wave can be stored in the capacitor, so that the transmission processing unit can be driven by the stored power even in a situation where only a relatively weak wireless power wave can be received. . In other words, the communicable area (responsible area) of the wireless transmitting / receiving device can be made wider.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
First, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating a schematic configuration of a wireless transmission / reception system 10 including a wireless transmission / reception device 12 according to the present embodiment, FIG. 2 is a diagram illustrating a schematic configuration of a power supply circuit 22 of the wireless transmission / reception device 12, and FIG. FIG. 4 is a diagram showing a temporal change of a signal voltage in each part (each point of A to C) of the circuit 22 (vertical axis: voltage, horizontal axis: time), and FIG. FIG. 3 is a diagram showing a temporal change of ON / OFF of an element (vertical axis: voltage or ON / OFF, horizontal axis: time).
[0009]
For example, the wireless transmission / reception device 12 configured as an RF-ID device or a non-contact type IC card receives a power wave (reception signal) from a transmission / reception device (for example, a read / write system for RF-ID) 14 as a response partner. It receives and outputs a transmission signal containing predetermined information as a response. The wireless transmission / reception device 12 performing such an operation includes the antenna 16, the signal processing unit 20, and the power supply circuit 22. The power wave (RF band) transmitted from the transmitting / receiving device 14 is received by the antenna 16 of the wireless transmitting / receiving device 12 and input to the power supply circuit 22. The power supply circuit 22 generates power for the signal processing unit 20. Note that the power generated here may be used as a power source for circuits other than the signal processing unit 20 or may be used together with another power source (for example, power generated by a separately provided solar cell or the like). . The signal processing unit 20 operates with the power generated by the power supply circuit 22 and generates a transmission signal in the RF band as a response to the reception signal. The generated transmission signal (RF band) is radiated from the antenna 16 and received by the transmission / reception device 14. The signal processing unit 20 performs a modulation process for putting predetermined information (for example, information indicating an identification code of the wireless transmission / reception device 12) on the transmission signal, and further obtains predetermined information included in the reception signal. It is also possible to execute demodulation processing and predetermined arithmetic processing based on the demodulated signal.
[0010]
Power supply circuit 22 includes a smoothing circuit 24, a booster circuit 26, a capacitor 38, and a power supply control circuit 28. The voltage waveform of the received signal at the time of input to the power supply circuit 22 (point A) is as shown in FIG. That is, the signal transmitted from the transmitting / receiving device 14 and received by the antenna 16 includes a burst that is intermittent at a predetermined period T. The waveform of the received signal (FIG. 3A) is changed by the smoothing circuit 24 as shown in FIG. That is, the smoothing circuit 24 has an integrating function and a rectifying function, and converts each burst into a pulse (only a positive component) having a predetermined period T (or a period substantially equal thereto). In the present embodiment, the smoothing circuit 24 includes the diode 30 and the capacitor 32 provided between the output terminal of the diode 30 and the ground.
[0011]
Then, the waveform of the signal (FIG. 3B) pulsed by the smoothing circuit 24 changes as shown in FIG. That is, in the present embodiment, the booster circuit 26 is configured as a so-called step-up circuit including the transformer 34 and the diode 36, and the voltage value Vc across the capacitor 38 provided between the output terminal of the diode 36 and the ground is equal to the input voltage. It becomes higher than the maximum voltage value Vb of the pulse to be performed.
[0012]
The power supply control circuit 28 outputs the power stored in the capacitor 38 as power for the signal processing unit 20 and other circuits. Specifically, the power supply control circuit 28 includes a switching element 40 and a control signal output circuit 42. The control signal output circuit 42, for example as shown in FIG. 4, inputs the ON signal for closing the power supply path 44 voltage across value Vc is the switching element 40 becomes higher than the first threshold value V _th1 of the capacitor 38 Then, the electric power stored in the capacitor 38 is released. On the other hand, the control signal output circuit 42 inputs an OFF signal for opening the power supply path 44 to the switching element 40 when the voltage value Vc between both ends becomes lower than the second threshold value _Vth2 , and the signal boosted by the booster circuit 26 Is stored in the capacitor 32. It is preferable that the second threshold value V _{th2 be} set slightly higher than the operation lower limit voltage of the signal processing unit 20.
[0013]
As described above, according to the present embodiment, since the power of the received signal can be accumulated to obtain the drive power of the signal processing unit 20 and other circuits, even when the strength of the received signal is relatively small, A response signal can be sent. Further, the communicable area (responsible area) for the transmission / reception device 14 becomes wider.
[0014]
Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 5 is a diagram illustrating a schematic configuration of a power supply circuit 52 of the wireless transmission / reception device 12, and FIG. 6 is a diagram illustrating a temporal change of a signal voltage in each part (each point of E to G) of the power supply circuit 52 (vertical axis: voltage , Abscissa: time). The power supply circuit 52 according to the present embodiment can be used in place of the power supply circuit 22 according to the first embodiment. The power supply circuit 52 includes the same components as those of the power supply circuit 22 according to the first embodiment, but the same reference numerals are given to the same components, and redundant description will be omitted.
[0015]
The power wave transmitted from the transmission / reception device 14 in the wireless transmission / reception system according to the present embodiment is different from that of the first embodiment. That is, the power wave transmitted in the present embodiment includes a burst of a predetermined cycle as shown in FIG. 3A only in a specific frequency band, and other frequency bands (however, at least a part of the band is 6D is included in a band that can be received by the wireless transmitting / receiving device 12 and can be processed by the power supply circuit 52, the signal processing unit 20, and the like. Then, the booster circuit 26 is made to function by driving the switching element 62 with a burst of a predetermined cycle, and a continuous burst is used as a power wave to be boosted by the booster circuit 26. By doing so, the amount of power obtained by the power wave itself increases as compared with the case where the boost target is an intermittent burst as in the first embodiment.
[0016]
In order to realize the above effects, the power supply circuit 52 according to the present embodiment controls the switching element 62 provided between the primary side of the transformer 34 and the ground and its ON / OFF as shown in FIG. And a control circuit 54. Note that the smoothing circuit 24, the boosting circuit 26, the capacitor 38, and the power supply control circuit 28 can be the same as the power supply circuit 22 (FIG. 2) according to the first embodiment.
[0017]
The control circuit 54 includes a band-pass filter 56, and extracts only a frequency band including a burst having a predetermined period T as shown in FIG. Thereafter, the signal waveform changes through a diode 58 and a capacitor 60 similar to those of the smoothing circuit 24, and changes into a pulse shape having a predetermined period T as shown in FIG. This pulse signal is input to the gate of the switching element 62, and the switching element 62 is turned ON / OFF.
[0018]
The booster circuit 26 according to the first embodiment boosts the voltage by shaping the waveform of the input signal into a pulse having an appropriate period. However, in the present embodiment, the booster circuit 26 includes a switching element. The voltage is increased by turning ON / OFF 62 at an appropriate cycle. Therefore, in a frequency band other than the frequency band from which the pulse-like signal is based, the signal can be transmitted as a continuous burst as shown in FIG. For this reason, the power amount of the signal increases as compared with the first embodiment, and the power amount generated by the power supply circuit 52 increases accordingly.
[0019]
【The invention's effect】
As described above, according to the present invention, since the power of the received signal is accumulated and used as the power source of the signal processing unit, there is a high possibility that the transmission processing unit can be driven even in an environment where the communication state is not good. . That is, the communicable area (responsible area) of the wireless transmitting / receiving device can be made wider.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a wireless transmission / reception system according to an embodiment of the present invention.
FIG. 2 is a schematic configuration diagram of a power supply circuit in the wireless transmission / reception device according to the first embodiment of the present invention.
FIG. 3 is a diagram illustrating a temporal change of a signal voltage in each part of the power supply circuit according to the first embodiment of the present invention.
FIG. 4 is a diagram showing a temporal change of a voltage between both ends of a capacitor of the power supply circuit according to the first embodiment of the present invention.
FIG. 5 is a schematic configuration diagram of a power supply circuit in a wireless transmission / reception device according to a second embodiment of the present invention.
FIG. 6 is a diagram illustrating a temporal change of a signal voltage in each part of a power supply circuit according to a second embodiment of the present invention.
[Explanation of symbols]
Reference Signs List 10 radio transmission / reception system, 12 radio transmission / reception device, 14 transmission / reception device, 16 antenna, 20 signal processing unit, 22, 52 power supply circuit, 24 smoothing circuit, 26 booster circuit, 28 power supply control circuit, 30 diode, 32 capacitor, 34 Transformer, 36 diode, 38 capacitor, 40 switching element, 42 control signal output circuit, 44 power supply path, 54 control circuit, 56 bandpass filter, 58 diode, 60 capacitor, 62 switching element.

Claims (5)

A transmission processing unit that performs a predetermined process including at least modulation to transmit a transmission signal,
A smoothing circuit for smoothing a burst of a predetermined cycle included in the received signal to generate a pulse-like signal of the cycle,
A booster circuit including a transformer for boosting the pulse signal,
A capacitor for storing the power of the signal boosted by the booster circuit;
With
A wireless transmission / reception device that uses power stored in the capacitor as power supply power of the transmission processing unit. A transmission processing unit that performs a predetermined process including at least modulation to transmit a transmission signal,
A smoothing circuit for smoothing a burst of a predetermined cycle included in a predetermined frequency band of the received signal to generate a pulse-like signal of the cycle,
A booster circuit including a switching element that is turned on / off by the pulse signal and a transformer that is provided in series with the switching element and boosts the reception signal;
A capacitor for storing the power of the signal boosted by the booster circuit;
With
A wireless transmission / reception device that uses power stored in the capacitor as power supply power of the transmission processing unit. A voltage detection unit that detects a voltage between both electrodes of the capacitor,
A second switching element that switches between opening and closing of a power supply line that supplies at least the power stored in the capacitor to the transmission processing unit;
A power supply control unit that controls ON / OFF of the second switching element based on a voltage value detected by the voltage detection unit;
The wireless transmission / reception device according to claim 1 or 2, further comprising: Any one of claims 1-3,
A signal transmitting device that transmits a signal including the burst of the predetermined period toward the wireless transmitting and receiving device,
A communication system including: A signal transmission device for transmitting a signal including the burst of the predetermined period to one of the wireless transmission / reception devices according to claim 1.

Images