Abstract:
A rechargeable hearing aid including an internal power unit such as a lithium ion battery having a short recharging time and a portable hearing aid charging and protection system for charging it. The charging system includes a protection system to prevent overheating and overcharging of the battery, an interface apparatus such as a Micro-USB connector, an induction charging device, a wireless induction charging device, or other suitable charging system interface apparatus to uniquely couple a charging power source, the charging and protection system and the internal power unit together. Among other features, the charging system communicates with the hearing aid to protect it by automatically turning off the hearing aid power while charging the hearing aid battery, turning the hearing aid power back on when charging is complete, and stepping the normal output voltage of the power unit down to the much lower operating voltage of the hearing aid.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Patent Application Ser. No. 62/133,063 filed Mar. 13, 2015, the entire disclosure of which is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to a rechargeable hearing aid. More specifically, the present invention relates to a rechargeable hearing aid and a charging and protection system for charging the hearing aid. 
       BACKGROUND OF THE INVENTION 
       [0003]    Over 95% of the hearing aids in the current marketplace use disposable batteries, which require frequent replacement by the hearing aid user. Replacing hearing aid batteries is a time consuming, expensive and frustrating process, not only due to the relatively small size of such batteries (a No. 10 battery is smaller than the end of a pencil, approximately 4 mm in diameter and 2.5 mm thick), but also due to the physical limitations of a typical hearing aid wearer. A person suffering from hearing loss may be in his or her senior years and suffer from failing eyesight, arthritis, tremors, lack of dexterity and other peripheral neuropathic conditions that render handling a small object of hearing aid battery-size difficult, if not impossible. 
         [0004]    Hearing aid battery life is not easily predictable, inasmuch as it may depend upon usage, individual hearing aid power requirements, temperature, environment and other conditions of use. Accordingly, generally a user will not know when the battery in his or her hearing device will require changing. In many instances, a “low battery” alert function may be the first and only indication a wearer will receive that a replacement is needed. This can occur in the most inconvenient of situations, for example, in a business meeting, a restaurant or a theater where not only the wearer&#39;s ability to participate in and enjoy the activity is interrupted, but lighting conditions may be so subdued that the wearer may have to simply remove the hearing device until a more opportune time for changing the battery arises. Loss of the sound amplification and hearing assistance provided by the hearing aid when the battery dies will result if the wearer does not replace the battery in a short period of time following the alert. Moreover, under such circumstances, proper disposal of the exhausted battery will be an issue. It is estimated that over 15 billion disposable hearing aid batteries are consumed world-wide annually. One can only imagine the adverse environmental impact that improper recycling of these materials is having globally. 
         [0005]    Hearing aids employing rechargeable batteries have been known in the art for some time. Some initial versions, nonetheless, still required that the battery be removed for recharging and then be reinstalled in the hearing aid. However, may hearing aids used sealed NiCad batteries, which required that the whole hearing aid be returned for servicing. Thus, the aforementioned problems associated with physical manipulation of the battery were not addressed. Subsequent advances in hearing aid and battery technology led to the development of hearing aids having rechargeable batteries that did not have to be removed for charging. For example, the hearing aid recharging system disclosed in U.S. Pat. No. 4,379,988 issued to Mattatall employs an inductive charging system to recharge a hearing aid battery without having to remove it from the device. More recently, U.S. Patent Application Publication No. US 2014/0153759 A1, published by Cantin on Jun. 5, 2014, discloses an induction recharging system for a rechargeable in-the-ear hearing aid. Cantin&#39;s apparatus eliminates the need to remove the hearing aid battery for recharging. However, the recharging system of Cantin&#39;s design does not address the problems associated with battery memory or overcharging, problems arising from the naturally occurring phenomenon of hysteresis. Hysteresis is the dependence of the output of a system not only on its current input, but also on its history of past inputs. The dependence arises because the history affects the value of an internal state. To predict its future outputs, either its internal state or its history must be known. 
         [0006]    U.S. Pat. No. 7,620,195, issued Nov. 17, 2009 to Bradley et al. for a Rechargeable Hearing Aid (the &#39;195 patent), discloses a rechargeable hearing aid and induction recharging system that provides acoustic communication between the hearing aid and the charger to prevent overcharging. However, the hearing aid device and recharging system disclosed in the 195 patent uses a nickel-metal-hydride (NiMH) battery, which requires a relatively long charging time (approximately six or more hours) and a customized charger, which is not convenient to transport while travelling or to replace should one lose it or fail to pack it for travel. 
         [0007]    In view of the foregoing, it will be apparent to those skilled in the art that a need exists for an improved rechargeable hearing aid and charging system that is readily transportable, does not require battery removal from the hearing aid for recharging, provides extended hours of battery usage and a large number of recharging cycles before replacement, and provides programmable control over the charging process to prevent overheating and overcharging of the battery. 
       SUMMARY OF THE INVENTION 
       [0008]    In an embodiment, the hearing aid battery recharging system of the present invention addresses the aforementioned problems associated with the prior art by providing a portable hearing aid charging and protection system for recharging a rechargeable hearing aid using a lithium ion battery having a short recharging time. The recharging system including a protection system to prevent overheating and overcharging of the battery, an interface apparatus for coupling a power source to the charging and protection system such as a Micro-USB connector, an induction interface system, a wireless induction interface system, or other suitable charging system coupling or interface apparatus to uniquely connect a power source to the hearing aid charging and protection system and the battery so that, among other features, the charging system will communicate with the hearing aid to protect it by automatically turning off the hearing aid power while charging and turning the hearing aid power back on when charging is complete. 
         [0009]    These and other features of the present invention will be apparent from the accompanying drawings, detailed description of the invention and the appended claims. As will be realized, the present invention is capable of modifications in various aspects, all without departing from the spirit and scope of the instant disclosure. While various embodiments are disclosed, still other embodiments will become apparent to those skilled in the art from the following detailed description and drawings which are to be regarded as illustrative in nature and not restrictive. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a side perspective view of a rechargeable hearing aid in accordance with an embodiment of the present invention; 
           [0011]      FIG. 2  is an exploded side elevation view of the rechargeable hearing aid of  FIG. 1  which is expanded to show the elements thereof in greater detail; 
           [0012]      FIG. 3  is a side elevation sectional view of the operational components of the rechargeable hearing aid of  FIGS. 1 and 2  having the housing removed to show the internal operational components thereof in greater detail; 
           [0013]      FIG. 4  is a side elevation sectional view a rechargeable hearing aid in accordance with an embodiment; 
           [0014]      FIG. 5  is a side elevation sectional view of a rechargeable hearing aid and a Micro-USB connector in accordance with and embodiment; 
           [0015]      FIG. 6 .A. is a circuit diagram of the common Micro USB charging interface portion of the rechargeable hearing aid charging protection circuit in accordance with an embodiment; 
           [0016]      FIG. 6 .B. is a circuit diagram of the charging control circuit portion of the rechargeable hearing aid charging protection circuit in accordance with an embodiment; 
           [0017]      FIG. 6 .C. is a circuit diagram of the charging protection circuit portion of the rechargeable hearing aid charging protection circuit in accordance with an embodiment; 
           [0018]      FIG. 6 .D. is a circuit diagram of the automatic switch-off circuit portion of the rechargeable hearing aid charging protection circuit in accordance with an embodiment; 
           [0019]      FIG. 6 .E. is a circuit diagram of the voltage transfer circuit portion of the rechargeable hearing aid charging protection circuit in accordance with an embodiment; 
           [0020]      FIG. 7 .A. is an enlarged view of a portion of a battery recharging control circuit in accordance with an embodiment; 
           [0021]      FIG. 7 .B. is a continuation of the enlarged view of the remaining portion of the battery recharging control circuit of  FIG. 7 .A. in accordance with an embodiment. 
           [0022]      FIG. 8  is a side perspective view of a rechargeable lithium polymer battery hearing aid power supply in accordance with an embodiment; 
           [0023]      FIG. 9  is a side elevation view of the power supply of  FIGS. 7 .A. and  7 .B.; 
           [0024]      FIG. 10  is a top plan view of the power supply of  FIGS. 7 .A.,  7 .B., and  8 ; 
           [0025]      FIG. 11  is a bottom view of the power supply of  FIGS. 7 .A,  7 .B.,  8 , and  9 ; 
           [0026]      FIG. 12  is a flexible printed circuit board for managing the charging process for charging the power supply illustrated in  FIGS. 8-11  in accordance with an embodiment; 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0027]    It should be noted that the present description is by way of illustration only, and that the concepts and examples presented herein are not limited to use or application with any single rechargeable hearing aid and recharging system. Hence, while the details of the rechargeable hearing aid and the recharging system and its components described herein are for the convenience of illustration and explanation with respect to the exemplary embodiments, the principles disclosed may be applied to other types of hearing aids and recharging systems without departing from the scope of the present invention. 
         [0028]    Referring now to  FIG. 1 , a rechargeable hearing aid in accordance with an embodiment of the instant invention is shown generally at  1 . The hearing aid includes a first housing or upper case cover  3 , a second housing or lower case cover  5 , the first and second case covers being structured and arranged to operatively engage one another to form an enclosure  7  to protect the internal operating components of the hearing aid, which are shown generally at  10  in  FIGS. 2-5 . The covers are retained in position by suitable fasteners such as retention screws or pins (not shown) which each extend through an aperture  8  formed in the upper case cove  3  attach to a respective retainer bracket  9  connected to the lower case cover  5 . The rechargeable hearing aid further includes a front microphone port  12 , a rear microphone port  14 , a volume control  16  extending through an aperture or slot  17  in the upper cover  3  and being operatively connected to a potentiometer  38  for controlling the volume directed into a wearer&#39;s ear, and a push button control  18  to select and activate control buttons  19  and various programs in the hearing aid. A threaded stem  20  is adapted to receive a sound tube (not shown) extending from the hearing aid enclosure  7  into a wearer&#39;s ear canal. 
         [0029]    As more clearly shown in  FIGS. 2-4 , the enclosure  7  contains a support structure or frame  22  mounted internally therein, the enclosure being divided into two chambers or cavities  24  and  26 . Cavity  24  is adapted to receive dual front and rear microphones  28  and  30  respectively, each extending through isolation tubes  32  positioned in the apertures  12  and  14  respectively formed in the upper case cover  3 . A speaker/transducer  34  is mounted in cavity  26  to transform electronic energy into acoustic energy and to direct the acoustic energy via stem  20  to a sound tube extending into a wearer&#39;s ear canal as described above. 
         [0030]    As best shown in  FIG. 2 , circuit board  36  is mounted within case covers  3 ,  5  and includes wiper/potentiometer  38  mounted thereon and adapted to cooperate with volume control  16  to adjust the hearing aid volume. A recharging control system circuit or chip, shown generally at  40 , is mounted on board  36  adjacent the potentiometer and includes the functional components of the battery recharging control circuit, including a digital signal processor (DSP)  41 , all of which will be described in greater detail below, an interface device or apparatus, by way of example, a universal charging cord interface  42  for a Micro-USB connector and attached charging cord (shown as  44  and  45  respectively in  FIG. 5 ) and a rechargeable power unit or battery  46 . It is to be understood, however, that other interface devices such as induction, wireless induction or other suitable interface coupling apparatus may be used without departing from the scope of the present invention. As will be described in greater detail below, by way of illustration and not of limitation, the rechargeable power unit may preferably be in the form of a lithium polymer battery; however, it is to be understood that other suitable power units may be used without departing from the scope of the present invention. 
         [0031]    Micro-USB cables are readily available, may be transported easily, and permit connection to any computer or via an adaptor to a standard electrical outlet, so that a wearer of the novel hearing aid of the present invention may quickly and conveniently recharge its battery or batteries at virtually any location. In a preferred embodiment, the battery is a high strength, lithium ion or lithium polymer battery which may be recharged fully in approximately ninety minutes, much more quickly than conventional prior art rechargeable hearing aids. 
         [0032]    Referring now to  FIGS. 6 .A.- 6 .E., the circuit diagrams of the elements of the recharging control system are illustrated in greater detail.  FIG. 6 .A. outlines the specifics of the universal Micro-USB interface  42  located inside the hearing aid housing, which permits the hearing aid wearer to recharge its battery as easily as he or she would recharge a cell phone. Interface  42  is a conventional Micro-USB interface found on most computers and laptops which is adapted to receive the standard Micro-USB connector attached to one end of the charging cord  45 . The other end of the charging cord may have either a second Micro-USB connector attached thereto for charging the hearing aid from the user&#39;s computer or a portable recharging device. Alternatively, the cord may include a standard two-prong wall plug attachment for charging from an electrical wall outlet, thereby making the hearing aid as easy for the user to recharge as his or her mobile telephone. 
         [0033]      FIG. 6 .B. depicts the circuit elements of a charging control circuit module  50 , which is operatively connected to USB interface  42  via input line  52 . Charging control module  50  includes microprocessor or digital signal processor (“DSP”)  54  which monitors and controls the charging current so that the battery recharging cycle is fast and stable without generating excessive heat. This circuit permits a full battery recharge within ninety (90) to one hundred twenty (120) minutes, a significant improvement over prior art recharging cycles of six hours or longer. 
         [0034]    A charging protection circuit module  60  is shown in  FIG. 6 .C. The protection circuit module includes microprocessor  62  which monitors the charging process, the charging current magnitude and the level of battery charge from moment to moment during the charging process to protect the battery against over-charging, over-current surges and short circuiting in the system. 
         [0035]      FIG. 6 .D. is a circuit diagram of an automatic power switch off circuit module  70 . Comprising at least one each of a conventional electronic sensing element and a switching element as known in the art, such as transistors  72 ,  74 , this module senses or detects the initiation of the charging process and automatically switches off the power of the hearing aid system so that, for example, the hearing aid will not emit any sound or noise during the charging process. This feature is particularly attractive to a user who recharges the hearing aid battery at night during normal sleeping hours. 
         [0036]    Referring to  FIG. 6 .E., the specifics of a voltage stabilizing circuit are shown in the circuit diagram. Effectively a transformer, this circuit module steps down the operating voltage of the power supply (the battery) from its conventional operating voltage of approximately 3.3 volts to a stable 1.4 volts, which is typically the maximum conventional operating voltage for the hearing aid system 
         [0037]      FIGS. 7 .A. and  7 .B. illustrate an enlarged circuit diagram of the elements of a recharging control system of the present invention in accordance with an embodiment  148  thereof. The control system  148  described below in accordance with an embodiment corresponds to the recharging control system or chip  39  mounted on board  36  shown in  FIG. 2 . The system includes module  150  which illustrates the specifics of the exemplary universal Micro-USB interface  42  located inside the hearing aid housing. As described above with respect to the embodiment of  FIG. 6 , interface  42  is a conventional Micro-USB interface found on most computers and laptops which is adapted to receive the standard Micro-USB connector attached to one end of the charging cord  45 . The other end of the charging cord may have either a second Micro-USB connector attached thereto for charging the hearing aid from the user&#39;s computer or a portable recharging device. 
         [0038]    A charging manager element  152  is electrically coupled to the Miro USB interface  150  via connector  154 . Charging control module  50  includes microprocessor or digital signal processor (“DSP”)  156  which monitors and controls the charging current so that the battery recharging cycle is fast and stable without generating excessive heat. 
         [0039]    The charging control system of the embodiment of  FIGS. 7 .A. and  7 .B. further includes a battery protection circuit module  160 , which, like the charging protect circuit module  60  of the embodiment of  FIG. 6 , includes a microprocessor  162  which monitors the charging process, the charging current magnitude and the level of battery charge from moment to moment during the charging process to protect the battery against over-charging, over-current surges and short circuiting in the system. The battery protection module is connected directly to an On-Off switch  170  and is structured and arranged to selectively turn the recharging control system on or off, the On-Off switch  170  being electrically connected to a voltage stabilizing module  175 . The voltage stabilizing module steps down the operating voltage of the power supply (the battery) from its conventional operating voltage of approximately 3.3 volts to a stable 1.4 volts, which is typically the maximum conventional operating voltage for the hearing aid system. 
         [0040]    Microcontroller or MCU controller  180  is mounted on board  36  and comprises electronic circuit control elements known in the art that are structured and arranged to monitor and control the recharging control system  148  via the hearing aid digital signal processor  41  (also shown in  FIG. 2 ), and module  190  illustrates the elements of the push button control  18  and control buttons  19  shown in  FIG. 2  and LED on-off and charging indicators (not shown) of the system. 
         [0041]    The rechargeable lithium ion battery hearing aid power supply  46  of the present invention is shown in greater detail in  FIGS. 8-11 . As best shown in  FIG. 8 , the power supply or battery  46  includes a housing  90  having an extension or tongue portion  92  extending laterally outwardly therefrom and adapted to be received in releasable engagement in a mating receptacle portion (not shown) in the hearing aid housing to facilitate replacement when the battery has exhausted its useful life. 
         [0042]    A flexible printed circuit board (“PCB”)  94  (illustrated in an extended view in  FIG. 12 ) having the elements of the circuitry of the recharging control system embodiment shown in  FIGS. 6 .A.- 6 .E., or, alternatively, the embodiment of  FIGS. 7 .A. and  7 .B., is shown in position on and extending around the battery  46  as it would be during charging mode. The circuit board includes a terminal or connector  96  secured to an upper portion  97  of a first or exterior side  98  of the PCB  94  and adapted to be connected to a positive terminal or pole of the battery via connector  96  on an opposite or interior side  100  of the circuit board  94 . For purposes of simplicity, each of the plurality of terminals or connectors will be described below in connection with a corresponding terminal or connector having the same number and positioned on the interior side of the PCB as shown in  FIG. 12 . Similarly located, connector  102  operatively connects to a negative terminal or pole pf the battery via connector  102 ′; connector  104  operatively connects to a charging indicator, for example a red LED light, via terminal  104 ′; connector  106  operatively connects to a charging complete indicator, for example, a green LED light, via terminal or connector  106 ′; connector  108  operatively connects to a negative terminal in the universal Micro-USB interface  42  located inside the hearing aid housing via connector  108 ′; and terminal or connector  110  operatively connects to a positive terminal in the universal Micro-USB interface via connector  110 ′. 
         [0043]    Referring now to both  FIGS. 11 and 12 , a plurality of terminals or connectors positioned on a lower portion  111  of the exterior side  98  of the PCB  94  is shown. The plurality of terminals includes terminal  112  operatively connected to a ground terminal on the microprocessor  54  via terminal  112 ′ positioned on the interior side  100  of the circuit board  94 ; terminal  114  operatively connected to a voltage; control circuit component of the microprocessor via terminal  114 ′; a power terminal  116  electrically coupled via terminal  116 ′ to a power control actuator (not shown) to turn the system on and off; an automatic temperature control/temperature switch terminal  118  connected via terminal  118 ′ to the automatic temperature control portion of the microprocessor; switch connector  120  which connects to the switch pin of the microprocessor via terminal  120 ′; and terminal  122  which is electrically connected to the direct audio input terminal (DAI terminal, an optional hearing aid feature), of the microprocessor via terminal  122 ′. 
         [0044]    Changes may be made in the above methods, devices and structures without departing from the scope hereof. It should thus be noted that the matter contained in the above description and/or shown in the accompanying drawings should be interpreted as illustrative and not in a limiting sense. The following claims are intended to cover all generic and specific features described herein, as well as all statements of the scope of the present method, device and structure, which, as a matter of language, might be said to fall there between.