WIRELESS ELECTRICAL CHARGING SYSTEM

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Patent Application

Number 60/945,572, entitled "Wireless Battery Charging From High

Frequency Waves," filed on June 21 , 2007, the disclosure of which is expressly incorporated herein by reference in its entirety.

[0002] This application also claims the benefit of U.S. Patent

Application Number 60/947,632, entitled "Wireless Battery Charging From

High Frequency Waves ," filed on July 2, 2007, the disclosure of which is expressly incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

[0003] The present invention relates to energy harvesting. More specifically, the present invention relates to attracting RF energy with special ceramics and converting the RF energy in DC power for applications, such as charging re-chargeable batteries.

BACKGROUND

[0004] Typically, consumer electronic devices require frequent charging by plugging an adapter into the wall. It would be desirable to eliminate the requirement for plugging a device into the wall for recharging. Although systems exist for harvesting RF energy, prior art systems typically require multiple antennas and are generally inefficient.

SUMMARY

[0005] A primary object of the present invention is to efficiently harvest electricity from ambient RF energy.

[0006] An apparatus for wirelessly re-charging a rechargeable battery includes a wireless receiver that amplifies received radio waves.

The wireless receiver is a tourmaline and zeolite composite. The apparatus also includes a patch antenna that filters the received radio

waves to usable RF signals; and a multiple circuits that process the usable RF signals to create refined electric power for the rechargeable battery.

[0007] A method for wirelessly re-charging a rechargeable battery includes creating a zeolite and tourmaline ceramic. The method also includes wirelessly receiving and amplifying radio waves with the tourmaline and zeolite ceramic, filtering the received radio waves to usable RF signals, and processing the usable RF signals to create refined electric power for the rechargeable battery.

[0008] Other objects, advantages and novel features, and further scope of applicability of the present invention will be set forth in part in the detailed description to follow, taken in conjunction with the accompanying drawing figures, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The accompanying drawings, which are incorporated into and form a part of the specification, illustrate several embodiments of the present invention and, together with the description, serve to explain the principles of the invention. The drawings are only for the purpose of illustrating embodiments of the invention and are not to be construed as limiting the invention. In the drawings:

Figs. 1 is an electrical schematic, according to an aspect of the present invention;

Figs. 2A and 2B are cross section and end views of components, according to an aspect of the present invention;

Fig. 3 shows a comparison of RF absorption, according to an aspect of the present invention;

Fig. 4 is circuit schematic showing an exemplary battery charging and protecting board, according to an aspect of the present invention; and Fig. 5 shows an exemplary system operation flow chart, according to an aspect of the present invention.

DETAILED DESCRIPTION

[0010] In order to increase efficiency to obtain sufficient DC voltage to charge a re-chargeable battery, tourmaline/zeolite ceramics are provided to improve RF absorption. Due to the increased efficiency, a single antenna can be used, as opposed to prior art systems that typically require multiple antennas. Moreover, no specific transmitting system is required.

[0011] Referring to Fig. 1 , an embodiment of the present invention will now be described. An integrated circuit 100 is shown. The components of the integrated circuit 100 will now be described in detail. [0012] A tourmaline/zeolite ceramic 1 receives RF signals and significantly amplifies the signal. In one embodiment, the signal strength is increased by 5 times compared with a ceramic without the tourmaline/zeolite ceramic 1. The ceramic 1 absorbs RF signals across a wide range of frequencies and can include energy from a variety of sources such as fluorescent lights and cellular signals. [0013] In an exemplary embodiment, the ceramic is a piezoelectric bender part number AB1560B manufactured by Projects Unlimited Inc. The ceramic is supplemented with approximately a 1 mm coating along the exposed tourmaline surface. The coating includes a mixture of about equal parts tourmaline, zeolite, and epoxy. The mixture is added to the ceramic from a dropper, and then heated to 120F to uniformly distribute the coating along the exposed surface, and also extend about 5% beyond the surface of the tourmaline surface. The ceramic 1 receives a very wide range of frequencies. Although a piezoelectric ceramic is described, any zeolite/tourmaline composite 1 on a substrate could perform the signal amplification.

[0014] A patch antenna 2, preferably plated with .5 micro millimeters of platinum is also shown. The patch antenna filters the received RF signals to between 50 Hz and 3.5 GHz. In one embodiment, the patch antenna is a square having rounded corners and 24 turns, as better seen in Fig. 2a. In a preferred embodiment, the patch antenna is 8 mm wide, and 8 mm long, with each coil spaced approximately .5 mm apart.

[0015] In one embodiment, the patch antenna 2 is designed in accordance with the equations below. The design width W of the microstrip patch antenna 1 is given by

(1 )

where f _r is the frequency of operation of the antenna (or the resonant frequency); μ ₀ and ε _o are fundamental physical constants, and, ε _r is a dielectric constant of the substrate.

[0016] In the general case, the microstrip patch antenna 1 has a length L of half of a wavelength at its center frequency (e.g., 3.5GHz) which is given by

(2)

8 mm

where λ£ - D 4i : h *J— * ~ 0,5mm

Ereff = effective side length; and h = thickness = .01 mm

[0017] A transformer 3,4 is provided to convert the RF energy into voltage. A primary coil 3 receives the RF signal from the patch antenna 2 and outputs AC 0.7V/.05A. A secondary coil 4 increases the AC output to between approximately 2.0V/250 mA and 5.7 V/100 mA. In one embodiment, the transformer is part number 78253/35m, available from C&D Technologies, Inc.

[0018] An RF tuning circuit 5 is also provided. The tuning circuit 5 includes a spectrum analyzer (not shown) and a capacitor. The RF tuning circuit controls the radio frequency being received by the patch antenna 2. In one embodiment, the coil is tuned to receive a frequency zone of 50 Hz to 3.5 GHz. In one embodiment, the RF tuning circuit is implemented with a 2.9 pF capacitor, such as part # 06035J2R9BB, available from AVX Corporation. As is well known, the resonance frequency = 1/2 π λ/LC [0019] A germanium diode 6 rectifies the signal received from the

RF tuning circuit 5, converting AC to DC. An exemplary rectifier is IN45, 1 N4148 - 1/8 watt, available from Fairchild Semiconductor Corporation. [0020] After the signal is converted to DC, signal conditioning occurs. A low pass filter can be provided to filter the noise frequencies from the DC signal and can include capacitors 7, 9 and an inductor 8. An exemplary capacitor 7 is a .00029 μF capacitor, such as part number 06035JJ291 BB available from AVX Corporation. An exemplary inductor 8 is a 68 μH inductor, such as part number HK0603-68NJ, available from Kemet Corporation. An exemplary capacitor 9 is a 1 μF 10V capacitor,

such as part number GRM188F551A105ZA, available from Murata Manufacturing Co. Ltd.

[0021] In one embodiment, further signal conditioning prevents overcharging. An exemplary signal conditioning circuit includes a resistor 10, a transistor 11 , and a Zener diode 12. The resistor 10 can be a 100 Ohm 1/8 watt resistor that operates the transistor 11. An exemplary resistor is part number 06035J102K, available from AVX Corporation. The transistor 11 regulates the voltage and can be a 30V/500mA NPN type transistor, such as part number NTE85, available from NTE Electronics, Inc. In one embodiment, the transistor 11 outputs 4.5V. The Zener diode 12 also regulates voltage. An exemplary Zener diode is part number FLZ4V7B, available from Fairchild Semiconductor Corporation. In one embodiment, the Zener diode 12 converts a 4.7 V signal into a 4.5 V output.

[0022] A primary rechargeable battery 13 can be a back up capacitor, such as an NEC-TOKIN FG series FGOhI 03ZF, available from NEC-TOKIN Corporation.

[0023] An isolator 14 is provided around components 5, 6, 7, 8, 9, preventing RF interference that would impair operation of the tuning circuit 5, rectifier 6, and low pass filter 7, 8, 9. In one embodiment, the isolator is implemented with copper foil 14 mm x 14 mm in a rounded rectangle shape.

[0024] Outside the integrated circuit, other components can be provided to facilitate battery charging. Such components include a voltage detecting and switching circuit 16, a DC/DC converter circuit 18, a battery charging and protecting circuit 20, a battery pack 22, and a rechargeable battery 24. In one embodiment, the voltage detecting and switching circuit 16 is part number S1111 BA45 available from Seiko Instruments Inc., and the DC/DC converter circuit 18 is part number NKE0505, available from C&D Technologies, Inc. The battery charging and protecting circuit 20 is illustrated in more detail in Fig. 4, and can be

part number AAT3681 , available from Advanced Analogic Technologies, Inc.

[0025] Referring now to Figs. 2 and 2a, more explanation will be provided of the integrated circuit 100. A substrate 30 is provided within an integrated circuit (IC) package 32. A printed circuit board 34 connects via lead wires 36 to the outside components 16, 18, 20, 22, 24 (not shown). [0026] Exemplary substrate materials include brass and copper.

On top of the substrate 30 is the ceramic 1. The patch antenna 2 connects the circuit board 34 to the ceramic 1. Isolator 14 is shown separating the substrate 30 and ceramic 1 from surface mounted devices 3 - 13, which are not shown in detail in Fig. 2.

[0027] Fig. 2a shows in detail the portion designated by "a" in Fig.

2, and exemplary dimensions. In one embodiment, the ceramic 1 has a diameter of 12 mm, the patch antenna 2 has a width of 8 mm, the substrate has a diameter of 15 mm, and the IC package 32 has a width of 17 mm.

[0028] As seen in Fig. 3, RF absorption with tourmaline/zeolite ceramics is much better than without tourmaline/zeolite ceramics. [0029] Referring to Fig. 5, an exemplary system operation process flow will now be described. Initially, at step S10 the zeolite/tourmaline ceramic amplifies a wide range of received RF signals. At step S12 the patch antenna absorbs the appropriate RF signals. At step S14 the primary coil transforms the RF signal into voltage, and at step S16, the secondary coil amplifies the received RF signal. At step S18, the RF tuning circuit tunes the coil to receive signals having a frequency of less than 3.5 GHz. Next, at step S20, the alternating current is demodulated to direct current. At step S22 noise and low pass filtration occurs, and at step S24 the voltage is regulated for 4.5 volts.

[0030] It is then determined whether the voltage is 4.5 volts, at step

S26. If not, the process returns to step S24. Otherwise, at step S28 voltage switching occurs, and at step S30 DC/DC converting for protection occurs. Next, it is determined whether the system is enabled at

step S32. In one embodiment, the system is enabled when the voltage is greater than 4 volts. If enabled, at step S34 it is determined whether the power input voltage is greater than the under voltage lockout. If the input voltage is greater than the under voltage lockout, then at step S36 fault conditions are monitored to determine if the voltage is over voltage. If YES at step S36 or the system is not enabled (Step S32: NO), or the power input voltage is less or equal to the under voltage lockout (S34: NO), then the system shuts down at step S38. [0031] If not over voltage, at step S40 a preconditioning test occurs, determining if a minimum voltage is greater than a battery voltage. If not, at step S42 a current phase test occurs at step S42. The current phase test compares a battery current with a charge termination threshold current. If the battery current is less than or equal to the charge termination threshold current, then a voltage phase test occurs at step S44 The voltage phase test determines whether an battery voltage for end of charge is greater than a battery voltage. If the battery end of charge voltage is greater, at step S46 the charge is completed. [0032] After charge completion, at step S48 a recharge test repeats until a recharge voltage is greater than the battery voltage, at which time the process returns to step S42.

[0033] If the preconditioning test determines that minimum voltage is greater than the battery voltage, at step S50 preconditioning (i.e., trickle charging) occurs. Charge control then occurs at step S52 and the process returns to step S36.

[0034] If the current phase test indicates that the battery current is greater than the charge termination threshold current, at step S54 a constant charge mode is entered and the logic returns to step S52. [0035] If the voltage phase test determines that the end of charge battery voltage is greater than the battery voltage, at step S56 a constant voltage charge mode is entered. Subsequently, the logic returns to step S52.

[0036] The illustrations of the embodiments described herein are intended to provide a general understanding of the structure of the various embodiments. The illustrations are not intended to serve as a complete description of all of the elements and features of apparatus and systems that utilize the structures or methods described herein. Many other embodiments may be apparent to those of skill in the art upon reviewing the disclosure. Other embodiments may be utilized and derived from the disclosure, such that structural and logical substitutions and changes may be made without departing from the scope of the disclosure. Additionally, the illustrations are merely representational and may not be drawn to scale. Certain proportions within the illustrations may be exaggerated, while other proportions may be minimized. Accordingly, the disclosure and the figures are to be regarded as illustrative rather than restrictive. [0037] One or more embodiments of the disclosure may be referred to herein, individually and/or collectively, by the term "invention" merely for convenience and without intending to voluntarily limit the scope of this application to any particular invention or inventive concept. Moreover, although specific embodiments have been illustrated and described herein, it should be appreciated that any subsequent arrangement designed to achieve the same or similar purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all subsequent adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the description.

[0038] The Abstract of the Disclosure is provided to comply with 37

C. F. R. §1.72(b) and is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, various features may be grouped together or described in a single embodiment for the purpose of streamlining the disclosure. This disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more

features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter may be directed to less than all of the features of any of the disclosed embodiments. Thus, the following claims are incorporated into the Detailed Description, with each claim standing on its own as defining separately claimed subject matter. [0039] The above disclosed subject matter is to be considered illustrative, and not restrictive, and the appended claims are intended to cover all such modifications, enhancements, and other embodiments which fall within the true spirit and scope of the present invention. Thus, to the maximum extent allowed by law, the scope of the present invention is to be determined by the broadest permissible interpretation of the following claims and their equivalents, and shall not be restricted or limited by the foregoing detailed description.

[0040] Although the invention has been described with reference to several exemplary embodiments, it is understood that the words that have been used are words of description and illustration, rather than words of limitation. Changes may be made within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the invention in its aspects. Although the invention has been described with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed; rather, the invention extends to all functionally equivalent structures, methods, and uses such as are within the scope of the appended claims.