Abstract:
A medical device having a battery pack comprising an indicator, wherein the battery pack indicator indicates the status of the battery pack when the battery pack is disassociated from the medical device and indicates the status of the medical device when associated with the medical device.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 12/624,873 entitled “Medical Device Battery Pack,” filed Nov. 24, 2009 (now U.S. Pat. No. 7,855,010) which is a continuation of U.S. patent application Ser. No. 11/185,476 entitled “Medical Device Battery Pack System and Method for Providing Active Status Indication,” filed Jul. 20, 2005 (now U.S. Pat. No. 7,625,662), which is a divisional of U.S. patent application Ser. No. 09/960,204 entitled “Medical Device Battery Pack with Active Status Indication,” filed Sep. 21, 2001 (now U.S. Pat. No. 6,955,864). The complete disclosure of each of the above-identified applications is hereby fully incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to battery packs, and more specifically relates to battery packs for a medical device, where the battery pack includes an active status indicator. 
     BACKGROUND 
     Many known battery-powered medical devices, such as semi-automatic external defibrillator (“AED”) devices, rely on batteries to power electronics of the device, and, in the case of the AED device, to administer electric shocks to patients. For example, AED devices are used to provide electric shocks to treat patients for a variety of heart arrhythmias. The AED provides relatively high-level shocks to a patient, usually through electrodes attached to the patient&#39;s torso, to convert, for example, ventricular fibrillation to a normal sinus rhythm. 
     Studies have demonstrated that survival rates are high when defibrillation treatment is administered within the first few minutes following cardiac arrest. The likelihood of successful resuscitation, however, decreases by approximately 10 percent with each minute following sudden cardiac arrest. After ten minutes, very few resuscitation attempts are successful. Thus, it is advantageous to construct a portable AED to provide an operator with a better chance of responding to a patient in a timely fashion. The portable AED typically includes a portable power supply, such as a battery pack. 
     For a defibrillation pulse to be effective in terminating cardiac arrhythmia sufficient energy should reach the heart, through muscle, bone, organs and other tissues. To be effective, the battery pack should be able to deliver a high dose of energy when needed. Since batteries can lose energy over time, however, some battery packs include an expiration date to help an AED operator determine that the battery pack can deliver the necessary energy needed. The operator cannot tell many things from the expiration date, however, for example, whether the battery pack was previously used or whether the batteries of the battery pack contain sufficient energy to function properly. In other devices, the operator does not know the status of the battery pack until it is inserted into the medical device. 
     Thus, there is a need for an improved battery pack for a medical device such as an AED. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  illustrates a top sectional view of an AED with a battery pack installed. 
         FIG. 1B  illustrates a top sectional view of the AED with the battery pack removed. 
         FIG. 2  illustrates a bottom view of the battery pack. 
         FIG. 3  illustrates a side sectional view of the AED including the battery pack. 
         FIG. 4  illustrates a side sectional view of the battery pack including first and second battery units. 
         FIG. 5  illustrates a block diagram of circuitry contained with the battery pack and AED. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1A  illustrates a top sectional view of the Semi-Automatic External Defibrillator (“AED”)  100  that includes a battery system, for example battery pack  110 . The AED  100  is a device to treat cardiac arrest that is capable of recognizing the presence or absence of ventricular fibrillation or rapid ventricular tachycardia or other shockable cardiac arrhythmias, and is capable of determining, without intervention by an operator, whether defibrillation should be performed. Upon determining that defibrillation should be performed, the AED automatically charges and requests delivery of electrical energy to electrodes that attach to a patient to deliver the energy to the patient&#39;s heart. 
     The battery pack  110  provides power to components such as electronics and a charger located in the AED  100 . The charger charges a capacitor  564  ( FIG. 5 ) of the AED  100  that provides the electrical energy to the electrodes attached to the patient. The AED  100  includes a generally rectangular shaped battery well  120  that is constructed and arranged to house the battery pack  110 . The battery pack  110  is sized to slide in and out of the battery well  120  to releasably connect a power supply of the battery pack  110  to the AED  100 . 
       FIG. 1B  illustrates a top sectional view of the AED  100  and the battery well  120  with the battery pack  110  removed. An entrance  210  of the battery well  120  accommodates alignment of the battery pack  110  within the battery well  120 . 
       FIG. 2  illustrates a bottom view of the battery pack  110 . Referring to  FIGS. 1B and 2 , an opposite end of the battery well  120  includes a wedge-shaped feature  230  that corresponds to a wedge-shaped receptacle  235  located in the battery pack  110 . When inserting the removable battery pack  110  to the AED  100 , the battery pack  110  is guided along by the battery well  120  to the wedge-shaped feature  230 . The battery pack  110  is aligned at the end of its travel by the wedge shaped feature  230  in the battery well  120  via the corresponding wedge shaped receptacle  235  in the battery pack  110 . 
     Referring to  FIG. 1A , to maintain the battery pack  110  in a connected position relative to the AED  100 , the battery pack  110  includes a latch  130  that retains the battery pack  110  within the battery well  120  when the battery pack is fully inserted into the battery well  120 . An end of the latch  130  connects with a spring  132  to bias the latch in a normally extended position. In the normally extended position, a latching end  134  of the latch  130  extends to enter a corresponding slot  136  located in the AED  100 . The latch  130  is moveable in a plane parallel to the spring  132  to compress the spring  132  to release the latching end  134  from the slot  136 . When the latching end  134  is released from the slot  136 , an ejection spring  137  located on the AED  100  pushes on the battery pack  110  to eject the battery pack  110  from the battery well  120 . The battery pack  110  includes a slot  138  from which the latch  130  extends. Even in a fully contracted position, the latch  130  extends past the slot  138 . 
     The battery pack  110  also includes a printed circuit board (PCB)  140  including exposed electrical terminals  150  to connect the printed circuit board  140  to electrical circuitry contained in the AED  100 , as described in more detail below. 
     The PCB  140  includes electrical components that connect to circuitry of the AED  100  when the battery pack  110  is installed in the AED  100 . The battery pack  110  includes a window  160  that is located proximate to a visual indicator, such as light emitting diode (LED)  550  ( FIG. 5 ). The window  160  allows an operator to view the LED  550  when the battery pack  110  is removed from the AED  100 . Thus, the operator can determine a status of at least one of the AED  100  and the battery pack  110  independent of the battery pack  110  being connected to the AED  100 . It should be appreciated that the AED  100  could also include a window located proximate to the battery pack window  160  so that an operator can view the LED  550  when the battery pack is inserted in the AED  100 . 
       FIG. 3  illustrates a side sectional view of the AED  100  including the battery pack  110 . The electrical terminals  150  of the PCB  140  contact a connector  310  located within the AED  100 , to electrically connect the battery pack PCB  140  with an AED PCB  320 . 
       FIG. 4  illustrates a side sectional view of the battery pack  110 . The battery pack  110  includes a first power supply, such as battery unit  410 . The battery unit  410  powers essential power needs of the AED during a main operating mode, for example when the AED is powered on. An essential power need includes, for example, the power necessary to charge the capacitor  564  to delivery energy to the patient. The battery unit  410  is preferably not being drained of power when the AED is powered off. 
     The battery unit  410  includes one or more battery cells, or other power supplies, that are electrically connected together. The power supply may include other forms of energy storage, for example based on chemical or kinetic principles, such as a flywheel storage device. The battery cells can include, for example, 2/3 A size batteries and/or C size batteries. The number of batteries used varies depending on a particular application but typically includes five or ten 2/3 A size batteries or four C size batteries. The five 2/3 A size batteries or four C size batteries are connected in series. Also, two sets connected in parallel of five 2/3 A batteries connected in series can be used for the battery unit  410 . The battery unit  410  preferably powers electronics and a charger located in the AED  100 . 
     The battery pack  110  also includes a secondary power supply, such as secondary battery  420 . The secondary battery  420  powers at least a portion of at least one of the AED and the battery pack  110  in an alternate mode, such as when at least a portion of the AED is powered off. Those skilled in the art will appreciate that the secondary battery  420  could also be used to power the AED during other modes, such as a sleep mode or when the AED is powered on. The secondary battery  420  typically includes a single 9 Volt battery, but other power supplies could be used, such as other sized batteries or other forms of energy storage. In a preferred embodiment, the battery pack  110  accommodates replacement of the secondary battery  420 . The secondary battery  420  can be sized smaller than the battery unit  410  and contain energy sufficient to power, for example, electric circuitry of the AED  100  and the battery PCB  140 . 
     The secondary battery  420  can be used to power circuitry exclusive of a state of the battery unit  410  and without draining power from the battery unit. Diodes  502  ( FIG. 5 ) electrically isolate the battery unit  410  from the secondary battery  420 . Electric circuitry of the battery pack PCB  140  is described in more detail below with regard to  FIG. 5 . Such circuitry includes a socket to removably receive a memory device ( FIG. 4 ), such as a memory card  430  or a multi-media card (MMC). 
     When the AED  100  is powered on and attached to the patient, the memory card  430  records the patient&#39;s electrocardiogram (ECG) signals, audio signals received from a microphone located on the AED  100 , and other operational information such as results of an analysis done on the patient by software of the AED  100 . The memory card  430  may also hold files that may be used to upgrade the software of the AED  100  or to provide user training mode software for the AED. 
       FIG. 5  shows a block diagram illustrating battery pack circuitry  500  contained with the battery pack  110 , for example, on the battery pack PCB  140 , and main unit circuitry  505 . The circuitry  500  includes a main power switch  510 . The main power switch  510  connects with a digital logic, such as micro-controller  520 , that turns the main power switch  510  on and off and controls other circuitry  500  of the battery pack PCB  140 . In addition to or in place of the micro-controller  520 , the digital logic can also include a microprocessor, a programmable logic device (PLD), a gate array and a custom integrated circuit. Other digital logic could also be used such as a Programmable Interface Controller (PIC) manufactured by Microchip Technologies, located in Chandler, Ariz. 
     The micro-controller  520  connects with a main AED connector  530  that connects circuitry of the battery pack PCB  140  to circuitry of the AED  100 . When the operator engages a power switch  592  located on the AED  100 , the micro-controller  520  receives a signal from the main unit connector  530  indicating that the power switch has been engaged. Thereafter, the micro-controller  520  enables the main power switch  510  to provide an electrical power between the battery unit  410  of battery pack  110  and the electronics of the AED  100 . The battery pack PCB  140  also includes a main battery connector  540  to connect the battery unit  410  to the main unit connector  530  and other circuitry of the battery pack PCB  140 . 
     The micro-controller  520  also controls a visual indicator, such as LED  550  and an audio indicator, such as sounder  560  that are used to automatically communicate information to the operator. For example, when the AED  100  fails a self-test, the operator is notified by a chirping sound from the sounder  560 . Moreover, the LED  550  flashes green to indicate that a status of components of the AED  100  is within an acceptable operating range. Those skilled in the art can appreciate the opposite could be true, i.e., that a flashing light indicates a fault condition. According to a preferred embodiment, if the LED  550  is not flashing an error exists, for example, in the circuitry  500 , or the battery unit  410  or secondary battery  420  are depleted. The micro-controller  520  monitors a signal of a comparator connected to secondary battery  420  to monitor a status of the secondary battery  420 , for example, to determine whether or not power of the secondary battery  420  is low or depleted. 
     Regarding the main unit circuitry  505 , a digital signal processor (DSP)  562  processes instructions and data of the AED  100 . The DSP  562  connects with a charger circuit  563  and discharger circuit  565  to control the charging and discharging of main unit capacitor  564 . The capacitor charger  563  connects the battery unit  410  to the capacitor  564 . The capacitor  564  connects to a discharge circuit  565  that connects to patient interface  566  to deliver shocks to the patient. 
     The micro-controller  520  also controls a red and green LED  567 , or a red LED and a green LED, located on the AED  100 . The micro-controller  520  connects to the red and green LED  567 , for example, via pins of the main unit connector  530 . The micro-controller  520  causes the LED  567  to flash green when the AED  100  is operating properly and causes the LED  567  to flash red when components of the AED are not within the acceptable operating range, for example, a component of the AED  100  failed during a self-test procedure. If the LED  567  is not flashing when the battery pack  110  is installed into the AED  100 , components of the AED  100  and the battery pack  110  should be checked. The battery pack LED  550  is preferably disabled when the battery pack  110  is installed. 
     The secondary battery  420  powers the micro-controller  520 , the LED  550  and the LED  567 , which helps to maintain the integrity of the battery unit  410  that provides power to electronics and the capacitor charger located in the AED  100 . A secondary battery connector  570  connects the secondary battery  420  to the circuitry of the battery pack PCB  140 . 
     Continuing with  FIG. 5 , the two diodes  502  connected and oriented as illustrated, define an OR gate between the main power  410  and the secondary power  420 . An OR gate as used herein means a circuit configuration having two inputs and one output wherein the circuit elements make the inputs independent. The illustrative OR gate uses diodes  502  having the necessary orientation one to the other to make the inputs independent, such that one input is not affected by the other. Additionally, a switch  510  is located in series with the main power  410  before the OR gate. As stated above, the main power  410  has a voltage greater than the voltage of the secondary power  420 . As a result, the OR gate controls which power source, main power  410  or secondary power  420 , is powering the circuitry  500  in the battery pack  110 . More precisely, when the main power switch  510  is open, no power flows from the main power  410  to the circuitry  500 . Thus, the circuitry is powered by the secondary power  420  as the diode of the OR gate in series with the secondary power has an orientation that permits the power to flow. However, when the main power switch  510  is closed, power flows from the main power  410  into the OR gate. As the voltage of the main power  410  exceeds that of the secondary power  420 , the diode connected in series with the secondary power acts as a switch effectively “turning off” the flow of power from the secondary power. As those skilled in the art will appreciate, over time the main power  410  and the secondary power  420 , which are batteries, will be depleted differently. As a result, the power source having a “higher” voltage at any given time may change. The OR gate will still function as described; however, if the secondary power  420  has a higher voltage than the main power  410 , the main power  410 , when the switch  510  is closed, will be blocked from powering the circuitry  500 , due to the diode in series with the main power  410 . 
     The battery pack circuitry  500  also includes an electrically erasable programmable read only memory (EEPROM)  580  connected to the micro-controller  520  and the main unit connector  530 . The EEPROM  580  stores information that may be relevant to an owner, service person or operator of the AED  100 . The EEPROM  580  stores information regarding, for example, the number of shocks the battery unit  410  has been used for, that the AED  100  has been activated, the date of manufacture of the battery pack  110  and status information regarding a status of components of the battery pack  110  and the AED  100 . The DSP  562  of the AED  100  connects to a bus that connects to a real time clock (RTC)  590 , the EEPROM  580  and the micro-controller  520 . Typically once per power up of the AED  100 , the DSP accesses the RTC  590  to set a main unit clock of the AED  100  that is located in the DSP. 
     The main unit circuitry  505  also includes a switch  592 , such as an ON/OFF switch, that connects to the micro-controller  520  via the main unit connector  530 . A shock switch  594  connects to the DSP  562  to allow an operator to administer a shock to the patient. A speaker  596  and indicator LEDs  598  connect to the DSP  562  to supply instructions or other information to the operator. Front end circuitry  599  connects between the DSP  562  and the patient interface  566  to process and/or provide the DSP  562  with information from the patient. 
     While the invention has been described above by reference to various embodiments, it will be understood that many changes and modifications can be made without departing from the scope of the invention. It is therefore intended that the foregoing detailed description be understood as an illustration of the presently preferred embodiments of the invention, and not as a definition of the invention. It is only the following claims, including all equivalents, which are intended to define the scope of this invention.