Implantable medical device and power controlling method thereof

An implantable medical device includes a secondary coil for receiving an RF signal from the external terminal by an induced electromotive force excited by an external terminal primary coil. RF signal includes a power signal for energizing the medical device and data signal generated upon modulation of the power signal for use in controlling the medical device. The implantable medical device further comprises: a power processing block for converting the received power signal into DC for use by the implantable medical device; a data communication circuit activated by the DC supplied from the power processing block for demodulating the modulated data signal from the RF signal; a charge unit for charging a battery with the DC supplied from the power processing block; and a control unit to be operative by a power supply from the battery for controlling the implantable medical device according to the demodulated data signal.

TECHNICAL FIELD

The present disclosure in some embodiments relates to an implantable medical device. More particularly, the present disclosure relates to an implantable medical device which can be awakened to a power signal and a power controlling method thereof.

BACKGROUND

As is known, an implantable pulse generator, a cochlear implant, a deep brain stimulator, and such medical devices that are inserted into the body of human, animal, etc. maintain communication and power transfer with external devices by magnetic coupling for establishing a low-frequency magnetic field by using an inductive link coil. In particular, communication data and electric power are transferred from the external device to the implantable medical device by an induced electromotive force between a primary coil of the external device and a secondary coil of the implantable medical device. The implantable medical device having a secondary coil is configured with dozens of circuit components which respectively need power consumption to perform their assigned functions.

Here, each of the circuit components may be divided into a data communication section and an operative section. Medical devices have a rechargeable internal battery for supplying electric power to the respective circuit components.

In general, the implanting nature of such medical device inevitably limits the overall device size which in turn restricts the maximum allowable dimension of the battery to be employed. The limited battery capacity generally proportional to the small size results in undersized and low-capacity implantable medical devices which suffer from frequent recharging. This is the major factor in diminishing the usability of the implantable medical devices.

Therefore, a low power system for implantable medical devices is needed in practice for reducing the power consumption of the device components to the minimum by securing the most battery capacity available.

DISCLOSURE

Technical Problem

Some embodiments of the present disclosure provide implantable medical devices rechargeable with an RF signal and a power controlling method thereof.

Some embodiments of the present disclosure provide implantable medical devices which can be awakened by RF signal and a power controlling method thereof.

SUMMARY

At least one embodiment of the present disclosure provides an implantable medical device interworking with an external terminal having a primary coil, including a secondary coil configured to receive an RF signal from the external terminal by an induction of an induced electromotive force between the primary coil and the secondary coil, the RF signal including a power signal for energizing the implantable medical device and a data signal generated upon modulation of the power signal for use in controlling the implantable medical device. The implantable medical device further includes a power processing block, a data communication circuit, a charge unit and a control unit. The power processing block is configured to convert the power signal into a DC (direct current) power to be used by the implantable medical device. The data communication circuit is configured to be activated by the DC power supplied from the power processing block and to demodulate the modulated data signal from the RF signal. The charge unit is configured to charge a battery with the DC power supplied from the power processing block. And the control unit is configured to be operated by an operation power supplied from the battery and to control the implantable medical device according to the demodulated data signal.

Another embodiment of the present disclosure provides a power control method for an implantable medical device comprising converting an RF signal induced between a primary coil on an external terminal and a secondary coil on the implantable medical device into a DC power to be used by the implantable medical device; and supplying the converted DC power to a data communication circuit for performing a data communication with the external terminal.

Yet another embodiment of the present disclosure provides an implantable medical device interworking with an external terminal having a primary coil, including; a secondary coil configured to receive an RF signal from the external terminal by an induction of an induced electromotive force between the primary coil and the secondary coil, the RF signal including a power signal for energizing the implantable medical device and a data signal generated upon modulation of the power signal for use in controlling the implantable medical device. The implantable medical device further includes: a power processing block, a charge unit, a communication signal detector, a data communication circuit, and a control unit. The power processing block is configured to convert the received power signal into a DC power to be used by the implantable medical device. The charge unit is configured to charge a battery with the DC power supplied. The communication signal detector is configured to detect the data signal from the power signal. The data communication circuit is configured to be energized by the DC power supplied from the power processing block while the data signal is detected and to demodulate the modulated data signal. And the control unit is configured to be energized by an operation power supplied from the battery, to control the implantable medical device according to the demodulated data signal, and to selectively connect or disconnect the power supply from the battery depending on the presence of the data signal detected by the communication signal detector.

Yet another embodiment of the present disclosure provides a power control method of an implantable medical device, the power controlling method including detecting an RF signal induced from a primary coil provided at an external terminal to a secondary coil provided at the implantable medical device, the RF signal including a power signal for energizing the implantable medical device and a data signal generated upon modulation of the power signal for use in controlling the implantable medical device. The power controlling method further includes supplying a control unit, in response to a detection of the data signal, with an operation power from a battery of the implantable medical device and supplying a data communication circuit for communicating with the external terminal with a DC power from a power processor after a conversion from the RF signal. The power controlling method further includes cutting off a power supply to the control unit and the data communication circuit in the absence of the detection of the data signal.

DETAILED DESCRIPTION

Hereinafter, some embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description, like reference numerals designate like elements although the elements are shown in different drawings.

FIG. 1is a block diagram of an implantable medical system for illustrating an implantable medical device communicating with an external terminal according to at least one embodiment.

As shown inFIG. 1, an external terminal110supplies a power signal to an implantable medical device120in a non-contact manner. The electric power for use in the implantable medical device120includes a charging power for a battery within the implantable medical device and an operation power for a data communication circuit within the implantable medical device.

The external terminal110includes a power signal generator112, a data signal generator114, an amplifier116and a primary coil118.

First, the power signal generator112generates the power signal for energizing the implantable medical device120, for example, a power signal with a rectangular waveform having a frequency on the order of several MHz. The power signal generated by the power signal generator112is provided to the power amplifier116.

The data signal generator114generates a low frequency signal used for the operation of the implantable medical device120, for example, a data signal with a rectangular waveform having a frequency of several dozen to several hundred kHz. The data signal of the low frequency generated by the data signal generator114is provided to the power amplifier116.

The power amplifier116generates a sinusoidal waveform corresponding to the power signal of the rectangular wave provided from the power signal generator112and amplitude-modulates the sinusoidal waveform with the data signal to generate an RF signal to be transferred to the implantable medical device120. In the power amplifier116, the sinusoidal waveform is used as a carrier, which is modulated with the data signal from the data signal generator114. Therefore, a power signal and a data signal are included in the RF signal. In the present embodiment, the power amplifier116is implemented with a Class-E power amplifier.

The primary coil118generates magnetic field in response to the RF signal from the power amplifier116. When the external terminal110and the implantable medical device120approach each other within a proximity distance, the primary coil118produces an induced electromotive force in a secondary coil121provided at the implantable medical device120.

Further, the implantable medical device120according to the present disclosure includes the secondary coil121, a power processing block122, a data communication circuit123, a charge unit124, a voltage regulator125and a control unit126. For example, the implantable medical device120may include, but not limited to, an implantable pulse generator, a cochlear implant and a deep brain stimulator.

The power processing block122generates a charging power or an operation power necessary for the implantable medical device from the induced electromotive force by the induction to the secondary coil121. The power processing block122includes a resonator122aconfigured to generate an RF signal of a particular frequency band from the induced electromotive force excited in the secondary coil121, a rectifier122bconfigured to rectify the generated RF signal of a sinusoidal waveform into a DC electric power, a data communication circuit123configured to demodulate a modulated data signal from the RF signal and provide a demodulated data signal to the control unit126, and a regulator122cconfigured to regulate the rectified DC power and provide the regulated DC power to the data communication circuit123and the charge unit124.

The data communication circuit123operates during a communication with the external terminal110and may be less frequently used than the control unit126. With this point in view, embodiments of the present disclosure are implemented not to supply the DC power from the power processing block122to the data communication circuit123unless magnetic coupling occurs in the secondary coil121, but to supply the DC power straight from the power processing block122for communicating data with the external terminal110only when magnetic coupling occurs between the primary coil118and the secondary coil121. The charge unit124includes a charge circuit124aand a battery124b, and the charge circuit124acharges the battery124bby using a DC power provided from the power processing block122.

The regulator125is disposed between the charge unit124and the control unit126to regulate the operation power provided by the battery124band provide the regulated operation power to the control unit126.

The control unit126is provided with energy by the operation power from the battery124bto perform main functions, such as a heart stimulating operation of an implantable pulse generator, a nerve stimulating operation of a cochlear implant, and a brain stimulating operation of a deep brain stimulator, according to a data signal provided by the data communication circuit123.

FIG. 2is a block diagram of an implantable medical system for illustrating an implantable medical device communicating with an external terminal according to another embodiment.

As shown inFIG. 2, an external terminal210supplies a power signal used for generating an electric power to an implantable medical device220in a non-contact manner. The source of the electric power used by the implantable medical device220includes the source of a charging power for a battery within the implantable medical device and that of an operation power for a data communication circuit within the implantable medical device, as described below.

The external terminal210includes a power signal generator212, a data signal generator214, a power amplifier216, and a primary coil218.

The power signal generator212generates a power signal for energizing the implantable medical device220, for example, a power signal with a rectangular waveform having a frequency of several MHz. The power signal generated by the power signal generator212is provided to the power amplifier216.

The data signal generator214generates a low frequency signal required for the operation of the implantable medical device220, for example, a data signal having a frequency of several dozens to several hundreds of kHz, and the generated low frequency signal is provided to the power amplifier216.

The power amplifier216generates a sinusoidal waveform corresponding to the power signal of the rectangular wave provided from the power signal generator212and amplitude-modulates the data signal of the sinusoidal waveform generated by the data signal generator214to generate an RF signal. In the power amplifier216, the sinusoidal wave is used as a carrier which is amplitude-modulated with the data signal. Therefore, a power signal and a data signal are carried by the RF signal. In the present embodiment, the power amplifier216may be implemented with a Class-E power amplifier.

The primary coil218generates a magnetic field in response to the RF signal from the power amplifier216. When the external terminal210and the implantable medical device220approach each other within a proximity distance, the primary coil218induces an induced electromotive force on a secondary coil221provided at the implantable medical device220.

Further, the implantable medical device220includes the secondary coil221, a power processing block222, a charge unit223, a communication signal detector224, a control unit225, a first regulator226for regulating voltage, a switch227, a second regulator228and a data communication circuit229. The implantable medical device220may include, but is not limited to, an implantable pulse generator, a cochlear implant and a deep brain stimulator. The power processing block222generates a charging power or an operation power necessary for the implantable medical device220from the induced electromotive force by the excitation by the secondary coil221. The power processing block222includes a resonator222aconfigured to generate an RF signal of a particular frequency band from the induced electromotive force, a rectifier222bconfigured to rectify the sinusoidal waveform of the generated RF signal into a DC electric power, a data communication circuit229configured to demodulate a modulated data signal from the RF signal to provide a demodulated data signal to the control unit225, and a regulator222cconfigured to regulate the rectified DC power and provide the regulated DC power to the charge unit223and the second regulator228.

The charge unit223includes a charge circuit223aand a battery223b. The charge circuit223acharges the battery223bwith the DC power provided from the power processing block222.

The control unit225is powered by the operation power supplied from the battery223band performs main functions, such as a heart stimulating operation of an implantable pulse generator, a nerve stimulating operation of a cochlear implant, and a brain stimulating operation of a deep brain stimulator, according to a data signal provided by the data communication circuit229. Further, when the control unit225receives a shutdown mode entry command included in a data signal and no data signal is detected by the communication signal detector224, it performs control to interrupt the supply of the operation power to the related elements including the control unit225itself. In embodiments of the present disclosure, this state is referred to as a shutdown mode in which all the elements in the implantable medical device maintain turnoff state.

The implantable medical device220further includes the first regulator226and the switch227arranged between the control unit225and the charge unit223.

The first regulator226regulates the operation power provided by the battery223band provides the regulated operation power to the control unit225.

The switch227is selectively turned on/off pursuant to the control by the control unit225. Such a selective on/off operation of the switch227may either supply or shut off the operation power of the battery223bprovided to the control unit225. The second regulator228regulates the DC power provided by the regulator222cand supplies or interrupts the regulated DC power as an operation power to the data communication circuit229. For example, when a data signal is detected by the communication signal detector224, the second regulator228is enabled under the control of the control unit225to allow the DC power from the regulator222cto energize the communication circuit229. In contrast, when a data signal is not detected by the communication signal detector224, the second regulator228may be disabled under the control of the control unit225to interrupt the supply of the DC power from the regulator222c.

The reason why the embodiment shown inFIG. 2employs a separate second regulator228is that it is different from the embodiment shown inFIG. 1in which an electric power signal having an AC waveform enables supply of an electric power to a data communication circuit even without a data signal. The operation scheme of shutting off power supply to the data communication circuit229when the AC waveform of power signal is used only for charging purpose and in the absence of detected data signal as the embodiment shown inFIG. 2. The data communication circuit229operates during a communication with the external terminal210and may be thus less frequently used than the control unit225. Therefore, in the present embodiment reflecting this point, the operation power from the regulator222cis not continuously supplied. Instead, the data communication circuit229is powered by the operation power provided by the regulator222cwhile a data signal is detected, so as to enable the data communication circuit229to selectively perform the data communication with the external device210by the secondary coil221only when data exists for communication.

Further, the communication signal detector224, when it gets out of the shutdown mode, detects a communication signal as well as the induction of an induced electromotive force in the secondary coil221and rectifies a sinusoidal waveform of power signal from the resonator222ato temporarily supply the electric power to the control unit225. The temporary supply of the electric power by the communication signal detector224to the control unit225indicates the occurrence of communication with the external device210by magnetic coupling and it causes the control unit225to awake from the shutdown state.

In response to the temporary power supply, the control unit225turns on the switch227to allow the supply of electric power of the battery223bto the control unit225and related elements. In this way, with the assistance of the communication signal detector224, the control unit225turns on the switch227in response to an occurrence of a data communication while no electric power is provided from the battery223b.

When a data communication is performed between the external device210and the implantable medical device220by the resonator222a, the communication signal detector224detects a data signal which has been demodulated by the data communication circuit229. Upon detecting the data signal, the communication signal detector224notifies to the control unit225that a data communication between the external device210and the implantable medical device220is being performed. In response to the notification, the control unit225enables the second regulator228. Then, the electric power from the regulator222ccan be supplied to the data communication circuit229by the second regulator228.

While a data signal is not detected by the communication signal detector224, the second regulator228is disabled by the control unit225and the data communication circuit229is unable to receive electric power by the second regulator228.

Meanwhile, when a data signal provided by the data communication circuit229during the communication with the external device210includes a data transmission termination signal indicating that the external device210terminates its data transmission, the control unit225disables the second regulator228as the control unit225identifies that the communication data signal includes no more data.

When the data signal provided during the communication with the external device includes a shutdown command for the medical device, the control unit225may shut down the entire medical device by disabling the second regulator228and then turning off the switch227.

According to the present disclosure, the implantable medical device shuts off the power supply dedicated to a data communication circuit responsible for the data communication when detecting no data communication with an external terminal, and responsive to an electric power signal induced between the primary coil in the external terminal and the secondary coil in the implantable medical device for converting and supplying the same signal into a DC power for operating the data communication circuit, to thereby implement a low power consumption design of the implantable medical device.

In order to implement an even lower power consumption design of the implantable medical device in the present disclosure, while detecting no data communication with an external terminal, the implantable medical device shuts off the power supply dedicated to the data communication circuit and to the control unit and is responsive to a detection of a communication signal induced from a primary coil in the external terminal to a secondary coil in the implantable medical device for supplying the control unit and data communication circuit with an operative battery power in the implantable medical device and responsive to no detection of such communication signal for interrupting the operative battery power to the control unit and data communication circuit.

Although exemplary embodiments of the present disclosure have been described for illustrative purposes, those skilled in the art will appreciate that various substitutions, modifications and variations are possible, without departing from the technical ideas of the disclosure.