The present invention is generally directed to chargers for charging implantable battery-powered medical devices and more particularly to chargers which can charge a plurality of such devices.
The present invention relates to implantable medical devices for stimulating body tissue and sensing body parameters (i.e., microstimulators and microsensors) as are known in the art. See, e.g., U.S. Pat. Nos. 5,193,539; 5,193,540; 5,312,439; 5,324,316; 5,358,514; and 5,405,367; each of which is incorporated herein by reference in its entirety. Generally, such implantable devices are referred to herein as microdevices.
Such implantable microdevices are characterized by a sealed housing which contains electronic circuitry for producing small electric currents between spaced electrodes (or sensing body parameters via the spaced electrodes). By precisely implanting the microdevices proximate to targeted tissue, the currents will stimulate the tissue or sense a physiological parameter and thus such devices produce medically beneficial results.
Typically, such microdevices derive operating power from an internal coil that is inductively coupled to an external AC magnetic field produced, for example, by a drive coil placed proximate to the microdevice(s). An AC voltage induced in the internal coil of the microdevice is rectified and filtered to produce a DC operating voltage which is used to power the electronic circuitry or power a battery contained within which in turn powers the electronic circuitry. Such an arrangement requires that the user remain in close proximity to the drive coil to maintain sufficient power transfer to operate the microdevice, e.g., to maintain tissue stimulation.
Alternatively, such microdevices can operate from power received from an internal rechargeable battery. See, e.g., U.S. Pat. Nos. 6,164,284; 6,185,452; 6,208,894; and 6,315,721; each of which is incorporated herein by reference in its entirety. Such battery-powered devices can, dependent upon the treatment regimen, be distributed throughout a patient's body. While such battery-powered devices free the user from always remaining in close proximity to the drive coil (to maintain operation of the device), each such rechargeable device still requires periodic charging.
The present invention is directed to a full-body charger for charging one or more battery-powered devices which are configured for implanting beneath a patient's skin for the purpose of tissue, e.g., nerve or muscle, stimulation and/or parameter monitoring and/or data communication. Devices in accordance with the invention include a support structure, typically chair-shaped or bed-shaped, e.g., mattress-shaped, capable of supporting a patient's body while providing a magnetic field to one or more of the implanted devices using one or more coils mounted within or on the support structure. Consequently, in a preferred embodiment, all of the implanted devices can be charged during a single charging cycle and thus, the present invention minimizes the effort and charge time requirements for a patient and accordingly improves the patient's life style.
In accordance with a preferred embodiment of the present invention, a full-body charger for providing an alternating magnetic field to one or more electrically-powered devices implanted beneath the skin of a patient's body (wherein each of the electrically-powered devices is powered by a rechargeable battery mounted within each device) comprises: (1) a support structure configured to support a patient's body, (2) at least one coil configured for mounting within the support structure, proximate to one or more of the electrically-powered devices, for emitting a magnetic field substantially encompassing one or more of the electrically-powered devices implanted within the patient's body, and (4) a controller for periodically providing an AC signal to energize at least one of the coils, and wherein the controller additionally includes communication circuitry for periodically providing a control signal to the electrically-powered devices to selectively interrogate the status of the rechargeable battery mounted within and for receiving a status signal in response thereto.
In accordance with a significant aspect of the invention, the full-body charger communicates with each of the implanted devices, preferably by modulating the AC signal used to power the coil or otherwise emitting a modulated output signal from a transducer, to determine the status of the rechargeable battery mounted within each implanted device.
In a further aspect of the present invention, a plurality of coils may be located within (or proximate to) the support structure and the coils may be periodically, sequentially energized to charge implanted devices proximate to each coil. Accordingly, the fields emitted from any one coil will not interfere with the charging fields or communication signals of any other coil.
The novel features of the invention are set forth with particularity in the appended claims. The invention will be best understood from the following description when read in conjunction with the accompanying drawings.
The following description is of the best mode presently contemplated for carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of describing the general principles of the invention. The scope of the invention should be determined with reference to the claims.
The present invention is directed to a charging system for devices that are configured for implanting beneath a patient's skin for the purpose of tissue, e.g., nerve or muscle, stimulation and/or parameter monitoring and/or data communication. Devices for use with the present invention are comprised of a sealed housing, preferably having an axial dimension of less than 60 mm and a lateral dimension of less than 6 mm, containing a power source and power consuming circuitry including a controller, an address storage means, a data signal receiver and an input/output transducer. When used as a stimulator, such a device is useful in a wide variety of applications to stimulate nerves, muscles, and/or associated neural pathways, e.g., to decrease or relieve pain, stimulate specific muscles or organs to better carry out a body function (e.g., to exercise weak or unconditioned muscles or to control urinary incontinence), and the like. Preferably such implantable microdevices are individually addressable for control purposes via a magnetic, propagated RF wave, or ultrasonic signal.
In contrast,
In a preferred implementation, the power supply 102 comprises a rechargeable battery 104 used in conjunction with a charging circuit 122 to provide sufficient power for prolonged activation of the controller circuitry 106 and the stimulation circuitry 110. See, e.g., U.S. Pat. Nos. 6,164,284; 6,185,452; 6,208,894; and 6,315,721; which are incorporated herein by reference in their entirety.
In operation, a coil 116 receives power in the form of an alternating magnetic field generated from an external power source 118 (see
In a typical application (see
Both the controller circuitry 106 (via power input terminal 127a) and stimulation circuitry 110 (via power input terminal 127b) receive power from the battery 104 power output terminal 128. The power dissipation of circuitry within the implanted device 100 is minimized by the use of CMOS and other low power logic. Accordingly, the required capacity of the battery 104 is minimized.
The controller circuitry 106 controls the operation of the stimulation circuitry 110 using a controller 130 (preferably a state machine or microprocessor) according to configuration data within a configuration data storage 132 coupled to controller 130. The configuration data specifies various programmable parameters that effect the characteristics of the drive pulses generated by stimulation circuitry 110 as controlled by the controller 130. Preferably, each implanted device 100, e.g., microstimulator, can be actuated (enabled/disabled) or have its characteristics altered via communications with one or more devices external to itself. Accordingly, each implanted device 100 uses its address storage circuitry 108, e.g., an EEPROM, PROM, or other nonvolatile storage device programmed during manufacture, to identify itself (e.g., using an ID code comprised of 8 or more bits stored within). Alternatively, the address storage circuitry 108 can be comprised of a portion of an integrated circuit that is mask programmed to form all or a portion of the ID and/or the use of a laser trimming process to designate all or the remaining portion of the ID. In a further alternative implementation, the ID can be designated by a selection of jumpers, e.g., wire bonds, used individually or in combination with the use of a laser trimming process. In operation, an external device (e.g., charger 118) transmits a modulated magnetic, ultrasonic, or propagated RF command signal containing command information that includes an address field. When the implanted device 100 receives and demodulates this command signal to receive the command information within, it first determines whether there is a match to its address within its address storage circuitry 108 before processing the rest of its data. Otherwise, the command information is ignored.
In one configuration, alternating magnetic field 154 is amplitude modulated with this command signal. Receiver circuitry 114a detects and demodulates this command signal by monitoring the signal generated across coil 116 (preferably the same coil used for charging the rechargeable battery 104). The demodulated data is provided to a controller data input 134 via path 136 where its applicability to a particular implanted device 100 is determined. Alternatively, the command signal can modulate a propagated RF signal which can be detected in a similar manner by receiver 114a (configured to demodulate an RF signal) using coil 116 as an antenna or using a separate antenna, e.g., via electrodes 112a, 112b. Various modulation techniques may be used including, but not limited to, amplitude modulation, frequency modulation, quadrature amplitude modulation (QAM), frequency shift keying (FSK), quad phase, etc.
In a next configuration, an ultrasonic signal can be used to deliver this command signal to each implanted device 100. In this configuration, an ultrasonic transducer 138 located within the device 100 generates a signal 140 which is demodulated by ultrasonic demodulator 114b. This demodulated signal is then provided to an ultrasonic data input 142 via path 144 and processed in a manner similar to that described in reference to a magnetic signal. The ultrasonic implementation provides significant advantages in that a patient's body is primarily comprised of fluid and tissue that is conducive to passing an ultrasonic signal. Consequently, a control device located anywhere inside (or external but in contact with) the patient's body can communicate with each device 100 implanted within.
In a preferred embodiment, the implanted device 100 includes means for transmitting status and data to external devices. In an exemplary charging mode, it is preferable that each device 100 can individually communicate with charger 118 so that charger 118 can determine when all of the implanted devices 100 (or at least those within its operational, i.e., charging/communication, range) have been fully charged. Preferably, device 100 includes transmitter means to emit a magnetic signal modulated with this data. This transmitter means comprises modulator circuitry 146 which modulates, e.g., amplitude modulates, an AC voltage and delivers this modulated signal to coil 116 which emits a modulated magnetic signal. While this modulated signal can use a different carrier frequency from that of the AC signal used by the charger 118, it is preferable that the communication channel, e.g., the magnetic field 154 between the devices, be time-shared. In
Depending upon the number of implanted devices 100, their distribution within the patient's body and the magnitude of the magnetic field 154 emitted from the charger 118, the charger 118 may need to be relocated and additional charge cycles instituted to charge all of the devices 100. To simplify this procedure, the present invention is directed to a “full-body” charger that can charge all of the implanted devices 100 within a patient within a single charging cycle. (For the purpose of this application, a charging cycle corresponds to a single use of a charger 118 which may and generally does comprise a plurality of multiple on, off, and inquiry sequences of the charge coil 116 and communication channel.) Generally, the charging fields presented between two nearby coils will interfere with each other (dependent upon their separation). Accordingly, embodiments of the present invention, generally sequentially energize coils to avoid such interference. Advantageously, a single controller 162 with control switches (not shown) can power multiple coils (one at a time). Two exemplary “full-body” embodiments of chargers are shown in
Alternatively, ultrasonic means can be used to communicate status or other data from the implanted device 100 to an external device. In such an embodiment, an ultrasonic transmitter 168 under control of the controller 130 generates a modulated signal on line 170 that is emitted by ultrasonic transducer 138. As previously discussed, an ultrasonic signal efficiently passes through the body fluids and tissues and as such is a preferred communication means for communication between devices implanted within the patient's body, e.g., other microstimulators 100, and suitable for communication with external devices in contact with the patient's skin 12.
The use of magnetic or ultrasonic communication, i.e., transmitter and receiver, means are not mutually exclusive and in fact implanted devices 100 may include both. For example as shown in
Once all of the devices 100 within the operational range of one coil 158 indicate that they are charged, the charger 118 switches over to an essentially identical cycle for the next coil via next cycle path 204. The next cycle then repeats in a similar manner until all devices 100 are charged within the operational range of the next coil 158.
Once this process has been completed for each of the coils and each of the devices 100 within the operational range of each of their respective coils, the charging cycle is completed (see path 208).
Alternatively (see
When multiple communication modes/channels are used, full duplex communication may be achieved such that charging may occur essentially continuously, i.e., without breaks for receiving status communications from the implanted devices 100. Accordingly, while an alternating magnetic field with modulated command contained within may be used to supply power to recharge the batteries 104 in the implanted devices 100, a second communication channel, e.g., ultrasonic, propagated RF, etc., may be time shared by each of the implanted devices 100 to periodically provide status data without providing pauses in the charging field. Accordingly, in such a mode, the charging field may be presented essentially continuously (see the dashed lines 25O1–25ON of
While the invention herein disclosed has been described by means of specific embodiments and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims. For example, while full-body charging algorithms have been described that charge indefinitely until all of the devices within the operational range of the coils are fully charged, the algorithms can be easily modified to have a fail safe or predetermined time out, e.g., to charge for a maximum period of time and to abort independent of the battery status of the implantable devices or to charge for a fixed period time. It is therefore to be understood that within the scope of the claims, the invention may be practiced otherwise than as specifically described herein.
This application is a continuation-in-part of U.S. patent application Ser. No. 09/677,384, filed Sep. 30, 2000, now U.S. Pat. No. 6,564,807. U.S. Pat. No. 6,564,807 is a divisional of U.S. patent application Ser. No. 09/048,827, filed Mar. 25, 1998, now U.S. Pat. No. 6,164,284. U.S. Pat. No. 6,164,284 is a continuation-in-part of U.S. patent application Ser. No. 09/030,106, filed Feb. 25, 1998, now U.S. Pat. No. 6,185,452, and claims the benefit of U.S. Provisional Application No. 60/042,447, filed Mar. 27, 1997. U.S. Pat. No. 6,185,452 claims the benefit of U.S. Provisional Application No. 60/039,164, filed Feb. 26, 1997. Furthermore, the present application claims the benefit of U.S. Provisional Application No. 60/347,902, filed Oct. 18, 2001.
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Number | Date | Country | |
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Parent | 09048827 | Mar 1998 | US |
Child | 09677384 | US |
Number | Date | Country | |
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Parent | 09677384 | Sep 2000 | US |
Child | 10272229 | US | |
Parent | 09030106 | Feb 1998 | US |
Child | 09048827 | US |