Patent Publication Number: US-2011062788-A1

Title: Wirless power supply device

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to a power supply device, and more particularly to a wireless power supply device. 
     2. The Related Art 
     Generally speaking, a mobile low-power electronic product such as a mobile phone, a mouse and so on needs a power-storage device such as a battery for providing electric power to the mobile low-power electronic product. When the electric power of the power-storage device is depleted, users must charge the power-storage device by means of a power supply device. A conventional power supply device wirelessly transmits an electromagnetic wave generated by a magnetic induction coil therein, and then transforms the electromagnetic wave into electric power for the power-storage device. However, the power supply device can be only used in a short range because the frequency of the electromagnetic wave is relatively low, so the electromagnetic wave is attenuated rapidly that results in an inconvenience of charging the power-storage device. Therefore, a power supply device capable of overcoming the foregoing problem is required. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a wireless power supply device. The wireless power supply device is adapted for providing electric power to an exterior electronic appliance. The wireless power supply includes a transmitting unit and a receiving unit. The transmitting unit includes a power unit for providing power to a voltage-controlled oscillator circuit and a signal amplification unit, the voltage-controlled oscillator circuit for receiving the power and then generating corresponding radio signals, the signal amplification unit for amplifying the radio signals generated by the voltage-controlled oscillator circuit and a transmitting antenna module for transmitting out the radio signals amplified by the signal amplification unit. The receiving unit includes a receiving antenna for wirelessly receiving the radio signals transmitted by the transmitting antenna module and then transforming the radio signals into electric power for being provided to the exterior electronic appliance. 
     As described above, the wireless power supply device of the present invention utilizes the transmitting unit transmitting out the radio signals, and the receiving unit wirelessly receiving the radio signals and then transforming the radio signals into the electric power so as to provide the electric power to the exterior electronic appliance. The radio signal has a good anti-attenuation ability and can be transmitted in a relatively long range, so it is convenient to provide the electric power to the exterior electronic appliance. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be apparent to those skilled in the art by reading the following description, with reference to the attached drawings, in which: 
         FIG. 1  is a block diagram of a wireless power supply device according to the present invention; 
         FIG. 2  is a circuitry of a voltage-controlled oscillator circuit of the wireless power supply device of  FIG. 1 ; 
         FIG. 3  is a view of a transmitting antenna module of the wireless power supply device of  FIG. 1 ; and 
         FIG. 4  is a circuitry of a rectifying circuit of the wireless power supply device of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIG. 1 , a wireless power supply device  1  according to the present invention includes a transmitting unit  10  and a receiving unit  20 . The wireless power supply device  1  is used for providing electric power to a mouse (not shown) in this embodiment. 
     Referring to  FIG. 1  and  FIG. 2 , the transmitting unit  10  of the wireless power supply device  1  includes a power unit  11 , a voltage-controlled oscillator circuit  12 , a signal amplification unit  13 , an isolator  14  and a transmitting antenna module  15 . The power unit  11  is connected with the voltage-controlled oscillator circuit  12  and the signal amplification unit  13  for providing power to the voltage-controlled oscillator circuit  12  and the signal amplification unit  13 . In this embodiment, the power unit  11  is provided with 6V. The voltage-controlled oscillator circuit  12  includes a voltage-controlled oscillator VCO. The voltage-controlled oscillator VCO has a first pin TUNE, a second pin VCC, a third pin GND and a fourth pin RFout. The second pin VCC is drawn forth as a positive input terminal Vin+connected to the power unit  11 , and the third pin GND is drawn forth as a negative input terminal Vin− connected to ground. The first pin TUNE is on one hand connected to the positive input terminal Vin+ through a second resistor R 2 , and on the other hand connected to the negative input terminal Vin− through a first resistor R 1 . The fourth pin RFout is electrically connected with the signal amplification unit  13 . In this embodiment, the first resistor R 1  is a variable resistor. The voltage-controlled oscillator VCO is used for generating radio signals, and output frequency thereof is variable on account of a variable resistance of the first resistor R 1 . In this embodiment, the voltage-controlled oscillator VCO is able to output a radio signal with a frequency of 2.4 GHz. 
     Referring to  FIG. 1  and  FIG. 2  again, the signal amplification unit  13  used for amplifying the output radio signal from the voltage-controlled oscillator circuit  12  includes a first amplifier  131  and a second amplifier  132 . In this embodiment, the first amplifier  131  is a signal amplifier with a gain of 17.5 dB in condition that the output frequency of the voltage-controlled oscillator VCO is 2.4 GHz. The second amplifier  132  is a power amplifier and a gain of the second amplifier  132  is 14 dB with an output power of 1 W. One terminal of the first amplifier  131  is connected with the fourth pin RFout of the voltage-controlled oscillator VCO and another terminal of the first amplifier  131  is connected with the second amplifier  132 . One terminal of the isolator  14  is connected with the second amplifier  132  and the other terminal of the isolator  14  is connected with a feeding point K of the transmitting antenna module  15  for preventing the second amplifier  132  from being damaged by the reflection signal of the transmitting antenna module  15 . 
     Referring to  FIG. 1  and  FIG. 3 , the transmitting antenna module  15  includes a plurality of slice antennas  151 ,  152 ,  153 ,  154  arranged at a phased array and connected to the feeding point K respectively. Each of the slice antennas  151 ,  152 ,  153 ,  154  has a substantial rectangular radiation portion  1511 / 1521 / 1531 / 1541  and a connecting portion  1512 / 1522 / 1532 / 1542  connecting the corresponding radiation portion  1511 / 1521 / 1531 / 1541  to the feeding point K. The connecting portions  1512 ,  1522 ,  1532 ,  1542  have substantially equal lengths with one another so as to make the amplified radio signals feed back to the feeding point K by means of a substantial in-phase feed back. In this embodiment, the length of each of the radiation portions  1511 ,  1521 ,  1531 ,  1541  is substantially equal to a half of the wavelength of the radio signal generated by the voltage-controlled oscillator VCO. The transmitting antenna module  15  has a relatively high gain and a relatively large half-power beamwidth. 
     Referring to  FIG. 1  again, the receiving unit  20  is disposed in the mouse and includes a receiving antenna  21 , a rectifying circuit  22  electrically connected with the receiving antenna  21 , and a storage capacitor  23  electrically connected with the rectifying circuit  22 . The rectifying circuit  22  is further directly connected with a circuit of the mouse, and the storage capacitor  23  is also connected with the circuit of the mouse. The receiving antenna  21  is used for wirelessly receiving the radio signals transmitted by the transmitting antenna module  15  and then transforming the radio signals into electric power. In this embodiment, the receiving antenna  21  is a dipole antenna with a feeding portion (not shown) and a grounding portion (not shown). 
     Referring to  FIG. 1  and  FIG. 4 , the rectifying circuit  22  has functions of a voltage multiplier and a full-wave rectifier. The rectifying circuit  22  is used for rectifying the electric power from the receiving antenna  21  and includes a first diode D 1 , a first capacitor C 1 , a second capacitor C 2  and a second diode D 2  successively connected with one another in series to form a unidirectional path. A first input terminal P 1  is drawn forth from the connection location of the first diode D 1  and the second diode D 2 . A second input terminal P 2  is drawn forth from the connection location of the first capacitor C 1  and the second capacitor C 2 . The first input terminal P 1  and the second input terminal P 2  are electrically connected with the feeding portion and the grounding portion of the dipole antenna, respectively. A positive output terminal Vout+ is drawn forth from the connection location of the first diode D 1  and the first capacitor C 1 . A negative output terminal Vout− is drawn forth from the connection location of the second diode D 2  and the second capacitor C 2 . The positive output terminal Vout+ and the negative output terminal Vout− are on one hand directly connected with the circuit of the mouse, and on the other hand connected with the storage capacitor  23 . The rectifying circuit  22  provides the rectified electric power to the mouse directly when the mouse is in the effective transmission range of the radio signals transmitted by the transmitting antenna module  15 , and simultaneously charges the storage capacitor  23  with the rectified electric power. When the mouse is out of the effective transmission range of the radio signals transmitted by the transmitting antenna module  15 , the storage capacitor  23  provides the stored electric power to the mouse. In this embodiment, both the first diode D 1  and the second diode D 2  are schottky diodes for enhancing a switching efficiency of the rectifying circuit  22 . The storage capacitor  23  is an ultra-capacitor so as to store enough electric power for the mouse when the mouse is out of the effective transmission range of the radio signals. 
     As described above, the wireless power supply device  1  of the present invention utilizes the transmitting unit  10  transmitting out the radio signals, and the receiving unit  20  wirelessly receiving the radio signals and then transforming the radio signals into the electric power so as to provide the electric power to the mouse. The radio signal has a good anti-attenuation ability and can be transmitted in a relatively long range, so it is convenient to store the electric power in the storage capacitor  23  and further provide the electric power to the mouse. 
     The forgoing description of the present invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. Such modifications and variations that may be apparent to those skilled in the art are intended to be included within the scope of this invention as defined by the accompanying claims.