Implantable medical device having a safety unit

Abstract

An implantable medical device is provided. The medical device comprises an energy consuming part, a receiving unit comprising at least one coil configured for receiving transcutaneously transferred energy and transferring the received energy to the energy consuming part, a switch placed between a first point an a second point for switching off or switching on the electrical connection between the first point and the second point, and a safety unit. The safety unit is configured to control the switch for switching off or switching on the electrical connection between the first point and the second point based on a parameter deviating from a predetermined range. Furthermore, at least one of the following: the first point is the receiving unit and the second point is the energy consuming part: the first point is the energy consuming part and the second point is a ground; the first point is a first end portion of the coil and the second point is a second end potion of the coil: or the receiving unit comprises an impedance electrically connected to the coil, the first switch is arranged at a first end portion of the impedance, and a second switch is arranged at a second end portion of the impedance, such that the impedance can be electrically disconnected from the other portions of the implantable medical device.

Description

[0001]IMPLANTABLE MEDICAL DEVICE HAVING A SAFETY UNIT Technical field The present invention generally relates to an implantable medical device. In particular the present disclosure relatesto an implantable medical device having a safety unit.Background There are many electronic and medical devices designed for implementation within the human body. Examples includediagnostic recorders, treatment controllers, and pacemakers, just to mention a few. These devices play an important role in managingand treating various medical conditions, so as to allow the patient to live a more normal life. Some implantable devices requiresubstantial power for their operation. To minimize the need for invasive procedures while keeping the power source relatively small,some devices can be charged transcutaneously. Challenges are presented when medical devices having wireless charging technology is to be embedded in the bodyof a patient. For the purpose of ensuring minimal invasiveness and increasing patient comfort, the implantable devices may be designedas compactly as possible. Furthermore, these devices may be configured to receive a power transfer at a level sufficient to penetratethe skin and varying depths of body tissue. Additionally, it is of high important that these implantable devices are safe. Safety concernsfor implantable devices include overtemperature, damage to the patient, malfunctioning, and may generate a need for surgery. Despiteadvancements in the field, there remains a significant need for enhanced safety measures in the design and operation of the implantable medical devices. Summary The present disclosure aims to provide improved methods and devices for wirelessly transferring energy to medicalimplants and parts thereof.In particular, according to a first aspect of the present disclosure, there is provided an implantable medical device.The medical device comprises an energy consuming part, a receiving unit comprising at least one coil configured for receivingtranscutaneously transferred energy and transferring the received energy to the energy consuming part, and a switch placed between a first point an a second point for switching off or switching on the electrical connection between the first point and the second point. Themedical device may further comprise a safety unit. The safety unit is configured to control the switch for switching off or switching onthe electrical connection between the first point and the second point based on a parameter deviating from a predetermined range. Theimplantable medical device is configured such that least one of the following: the first point is the receiving unit and the second point is the energy consuming part; the first point is the energy consuming part and the second point is a ground; the first point is a first end portion of the coil and the second point is a second end potion of the coil; or the receiving unit comprises an impedance electrically connected to the coil, the first switch is arranged at a first end portion of the impedance, and a second switch is arranged at a second end portion of the impedance, such that the impedance can be electrically disconnected from the other portions of the implantable medical device.According to a second aspect of the present disclosure, there is provided an implantable medical device. The medicaldevice comprises an energy consuming part, a receiving unit comprising at least one coil configured for receiving transcutaneouslytransferred energy and transferring the received energy to the energy consuming part, and a first switch. The first switch is arrangedbetween the receiving unit and the energy consuming part for switching off the electrical connection between the receiving unit and theenergy consuming part. The medical device may further comprise a safety unit configured to control the first switch for switching offthe electrical connection between the receiving unit and the energy consuming part based on a parameter deviating from a predetermined range. According to a third aspect of the present disclosure, there is provided an implantable medical device. The medicaldevice comprises an energy consuming part, a receiving unit comprising at least one coil configured for receiving transcutaneouslytransferred energy and transferring the received energy to the energy consuming part, and a first switch. The first switch is arrangedbetween the energy consuming part and a ground for switching off the electrical connection between the energy consuming part and theground. The implantable medical device may further comprise a safety unit configured to control the first switch for switching off theelectrical connection between the energy consuming part and the ground based on a parameter deviating from a predetermined range. According to a fourth aspect of the present disclosure, there is provided an implantable medical device. The medicaldevice comprises an energy consuming part, and a receiving unit comprising at least one coil configured for receiving transcutaneouslytransferred energy and transferring the received energy to the energy consuming part. The receiving unit comprises an impedance unitconfigured to be electrically connected to the coil. The medical device may further comprise a first switch arranged at a first endportion of the impedance and a second switch arranged at a second end portion of the impedance unit, such that the impedance unit is electrically disconnected from the other portions of the implantable medical device when the first and / or the second switches are open.The medical unit may further comprise a safety unit configured to control the first switch and the second switch based on a parameterdeviating from a predetermined range. According to an embodiment, the first switch and the second switch are interconnected such that they operate concurrently. According to a fifth aspect of the present disclosure, there is provided an implantable medical device. The medicaldevice comprises an energy consuming part, a receiving unit comprising at least one coil configured for receiving transcutaneouslytransferred energy and transferring the received energy to the energy consuming part, and a first switch. The first switch is connectedto a first end portion of the coil and a second end portion of the coil. The medical device may further comprise a safety unit configuredto control the first switch for switching on the electrical connection between the first end portion of the coil and the second end portion of the coil based on a parameter deviating from a predetermined range. Embodiment according to any one of the first, second, third, fourth or fifth aspects will now be described. According to an embodiment, an initial state of the first switch is on, and / or the initial state of the second switch ison. According to an embodiment, an initial state of the first switch is off.According to an embodiment, the safety unit is configured to reset the first switch and / or the second switch to theinitial state on the condition that the transcutaneously transferred energy received by the safety unit is below a threshold. According to an embodiment, the first switch and / or the second switch is reset to the initial state if the safety unit is disconnected from a power supply. According to an embodiment, the safety unit comprises a fuse or circuit breaker that, if triggered, causes the first switch and / or the second switch to switch off or switch on, so that the switch is no longer in the initial condition. According to an embodiment, the fuse or the circuit breaker is triggered by the parameter exceeding a threshold. According to an embodiment, the parameter is related to at least one of: temperature of the medical device, temperature in the body of a patient, a voltage, a current, a power, an energy, a force, a pressure, or an insulation error. According to an embodiment, the safety unit comprises: a measurement unit configured to measure the parameter; and a controller configured to control the first switch or the second switch in response to the parameter deviating from a predefined allowed range of the parameter. According to an embodiment, the safety unit comprises a first latch circuit configured to control the first switch and / or the second switch. According to an embodiment, the first latch circuit is connected to a voltage limitation device to keep the energy supply of the latch circuitry active. According to an embodiment, the safety unit comprises a second receiving unit comprising at least one coil configured for receiving the transcutaneously transferred energy for powering the safety unit. According to an embodiment, the safety unit is configured to return the first switch and / or the second switch to an initial position on condition that the second receiving unit stops receiving transcutaneously transferred energy. According to an embodiment, the measurement unit is configured to measure a second parameter, different from the parameter. According to an embodiment, the second parameter is related to at least one of: a temperature of the medical device, a temperature in the body of a patient, a voltage, a current, a power, an energy, a force, a pressure, or an insulation error. According to an embodiment, the controller is configured to control the first switch and / or the second switch in response to the second parameter deviating from a predefined allowed range of the parameter. According to an embodiment, the receiving unit is configured to rectify an incoming alternating current. According to an embodiment, the energy consuming part of the implantable medical device is configured for storing energy received by the receiving unit. According to an embodiment, the energy consuming part of the implantable medical device is configured to exert a force on a body portion of the patient. According to an embodiment, the energy consuming part of the implantable medical device comprises an electrical motor and wherein the safety unit is configured for controlling the electrical motor. Afeature described in relation to one aspect may also be incorporated in other aspects, and the advantage of the feature isapplicable to all aspects in which it is incorporated. Other objectives, features and advantages of the present inventive concept will appear from the following detailed disclosure, from the attached claims as well as from the drawings. Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. Further, the use of terms "first", "second", and "third", and the like, herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. All references to "a / an / the [element, device, component, means, step, etc.]" are to be interpreted openly as referring to at least one instance of said element, device, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated. Brief description of the drawings The above, as well as additional objects, features, and advantages of the present inventive concept, will be better understoodthrough the following illustrative and non-limiting detailed description of the present inventive concept, with reference to the appended drawings, wherein: Figure 1 schematically shows an implantable medical device and an external device, for transferring wireless energyto the implantable medical device. Figure 2-5 schematically shows an embodiment of an implantable medical device comprising a safety unit for controlling energy received by the energy consuming part. Figure 6-7 schematically shows an implantable medical device and an external device, wherein the implantablemedical device comprises a safety unit. Figure 8 schematically shows a safety unit and a switch.The figures are not necessarily to scale, and generally only show parts that are necessary in order to elucidate the inventive concept, wherein other parts may be omitted or merely suggested. Detailed description The present disclosure is described in the following by way of a number of illustrative examples. It will be appreciated that these examples are provided for illustration and explanation only and are not intended to be limiting on the scope of the present disclosure. Instead, the scope of the present disclosure is defined by the appended claims. Furthermore, although embodiments be presented individually for the sake of focused discussion of particular features, it will be recognized that the present disclosure also encompasses combinations of the embodiments described herein. An overview of a system 100 comprising an transmitting unit 102 and an implantable medical device 110 will now be describedwith reference to Figure 1. The transmitting unit 102 is adapted to be arranged outside of a body. The implantable medical device 110 is adapted to be implanted into a body of a patient. The transmitting unit 102 comprises a transmitting coil 104 and a transmitting circuit106, wherein the transmitting coil 104 is electrically connected to the transmitting circuit 106. The transmitting unit 102 utilizes thetransmitting coil 104 to induce energy in the implantable medical device 110. The transmitting unit 102 may be a charger adapted tocharge the implantable medical device 110. There may be more than one transmitting unit 102 that transmits energy to the implantable medical device 110, and more than one transmitting unit 102 may transmit at the same time. The implantable medical device 110 is adapted to receive transcutaneously transferred energy. The implantable medical devicecomprises a receiving unit 111. The receiving unit 111 comprises a receiving coil 114. The receiving unit 111 comprises a receiving circuit 116and an impedance unit 118. The implantable medical device 110 further comprises an energy consuming part 112. Electrical connections 120electrically connect the receiving circuit 116, the receiving coil 114, and the impedance unit 118.In Figure 1, the receiving coil 114, the impedance unit 118 and the receiving circuit 116 are connected in parallel. The receivingcoil 114, the impedance unit 118 and the receiving circuit 116 may be connected in respect to each other in series, parallel, partially inseries and partially in parallel, or any other way. The receiving circuit 116 is preferably connected in parallel to at least a part of theimpedance unit 118. The implantable medical device further comprises a safety unit 113. In Figure 1, the safety unit 113 is arranged between thereceiving circuit 116 and the energy consuming device 112. The safety unit 113 may be connected to any component in the implantablemedical device 110. Examples of where the safety unit may be arranged will be discussed with reference to Figs. 2-5 and examples ofcomponents of the safety unit will be discussed with reference to Figs. 6-8. Electrical connections 120 electrically connect the energyconsuming part 112 to the receiving circuit 116. The electrical connections 120 may comprise wires, any electrical conducting material and / or any wireless connections. The implantable medical device 110 is configured to receive transcutaneously transferred energy from the transmitting unit 102 via the receiving coil 114. An electrical coupling 124 illustrates the electrical connection between the external transmitting unit 102and the implantable medical device 110. More specifically, the electrical coupling 124 illustrates the electrical connection between thetransmitting coil 104 and the receiving coil 114. The electrical coupling 124 is between the implantable medical device 110 and the transmitting unit 102, where skin may be if the implantable medical device 110 is implanted into the body of a patient. The transmitting circuit 106 is configured to generate an alternating current in the transmitting coil 104. The alternatingcurrent of the transmitting coil 104 induces a current in a receiving coil 114, such as the receiving coil(s) 114. The receiving coil 114 isadapted to be able to receive transcutaneously transferred energy, and the receiving circuit 116 is configured to transfer energy received by the receiving coil 114 to the energy consuming part 112. In Figure 1, one receiving coil 114 is illustrated. There may be morethan one receiving coil 114 comprised in the implantable medical device 110. If there is more than one receiving coil 114, the more than onereceiving coil 114 may be connected in series, in parallel, or a combination thereof wherein some may be connected in series and somemay be connected in parallel to each other. The energy consuming part 112 may comprise a medical implant. The energy consuming part 112 may comprise an energystoring device such as a battery, a device configured to exerting a force on the body it is implanted in, an electrical motor, a device formonitoring a condition of the body, a device for treating the body, a measuring device, a processor, or any other device suitable for amedical implant, or a combination thereof. The energy consuming part 112 may further comprise voltage stabilization unit, such as, forexample, a capacitor in parallel to other parts of the energy consuming part 112. In Figure 1, the energy consuming part 112 is electrically connected to an electrical ground, also referred to as a ground, 122.The ground 122 is a reference point in the electrical circuit that provides a common return path for electric current. The ground 122 isdesigned to safely manage the flow of electrical current. The energy consuming part 112 may be connected directly to the ground 122 orbe connected to a part of the receiving circuit 116. The receiving circuit 116 may comprise a connection to the ground 122. In Figure 1, an impedance unit 118 is illustrated as a capacitor connected in parallel to the receiving coil 114. The impedance unit118 may be connected in series with the receiving coil 114, in parallel to the receiving coil 114, or a combination thereof wherein someparts of the impedance unit 118 may be connected in series with the receiving coil 114 and other parts of the impedance 118 may beconnected in parallel to the receiving coil 114. The impedance unit 118 may comprise a capacitor, a inductance, a capacitor and resistance,an inductor and resistance, or a combination thereof. The impedance unit 118 may comprise a variable impedance. The impedance unit 118may comprise intrinsic resistance. The impedance unit 118 may be imbedded in the receiving circuit 116.The inductance of the receiving coil 114 and the impedance of the impedance unit 118 may contribute to a resonance frequencyof the implantable medical device 110. More specifically, the inductance of the receiving coil 114 and the impedance of the impedance unit118 may contribute to a resonance frequency of the receiving unit 111. If the frequency of the transcutaneously transferred energy pickedup by the receiving coil 114 is at, or close to, the resonance frequency, the current or the voltage may be at a resonance. At or close to a resonance, the received current and / or the voltage may be at or near a maximum. The receiving circuit 116 may receive an alternating current from the receiving coil 114. The receiving circuit 116 may rectifythe current from the receiving coil 114. The receiving circuit 116 may convert the alternating current obtained from the receiving coil into a rectified current provided to the energy consuming part 112. The receiving circuit 116 may comprise any type of rectifier, such as, for example, half-wave rectifier, full-wave rectifier, bridge rectifier, or center-tapped rectifier. The receiving circuit 116 may comprise arectifier that is controlled or uncontrolled. The current from the receiving circuit 116 that is provided to the energy consuming part 112may be, for example, half-way rectified, full-wave rectified, pulsating direct, smoothened, regulated, or direct. The receiving circuit 116may comprise a power transformation circuit, such as, for example, a transformer, or a DC-DC converter. A DC-DC converter maycomprise, for example, a step-down converter (such as a buck converter), a step-up converter (such as a boost converter), or a buck- boost converter. The receiving unit 116 may comprise controllers, switching devices, or controlling circuits for controlling thetransformation circuit. The receiving circuit 116 may comprise, for example, an impedance, wires, diodes, voltage limitation devices,amplifiers, or a combination thereof. The receiving circuit 116 may comprise diodes in parallel or in series to increase the resilience ofthe implantable medical device 200. The safety unit 113 is configured to intentionally control a short or open circuiting of electrical components. The safety unit 113may short the circuit or open the circuit between components of the implantable medical device 100 based on a parameter deviatingfrom a predetermined range. The safety unit 113 may intentionally control a short or open circuit by, for example, controlling a switch forswitching off or switching on the electrical connection between components of the implantable medical device 100. Which componentsthat may be will be discussed in further detailed with reference to Figs. 2-7. Furthermore, as will be discussed in more detail below withreference to Figs. 6 and 7, the safety unit may comprise a fuse or a circuit breaker for actuating the switching, and / or a controller to control the switching. In some examples, a parameter deviating from a predefined range may be sensed by a fuse or circuit breaker comprised in the safety unit being triggered. The safety unit 113 is thus configured to increase the safety of the implantable medical device 110. The safety unit 113 mayincrease the safety of the implantable medical device 110 by, for example, decoupling components of the implantable medical device 110.In some examples, the safety unit 113 may alter the resonance frequency of the implantable medical device 110. Advantages of the safetyunit 113 may include protecting the components of the implantable medical device 122. For example, if the receiving unit 111 provides the energy consuming part 112 with more energy than the energy consuming part 112 is configured to handle, the safety unit 213 may protect the energy consuming part 112. Protecting the energy consuming part 112 can be from, for example, an overvoltage or an overcurrent. The energy consuming part 112 being provided with more energy than it is configured to handle may cause excessive heat in the implantable medical device 200, the energy consuming part 112 may break and / or the energy consuming part 112 may become a safety risk for the user. The energy consuming part 112 being overloaded may result in electrochemical and electrophysical energy storages tobe overcharged, and / or the active circuits within the energy consuming part 112 may no longer be able to utilize the received energy,and / or protection mechanisms of the energy consuming part 112 may fail in effect. The energy consuming part 112 being overloaded may cause the parts of the implantable medical device 200 to, for example, overheat and / or become destroyed. A implantable medical device200 may be destroyed by, for example, overvoltage, overcurrent, high temperatures, thermal runaway, arching, physical destruction(such as explosions), or a combination thereof. Figures 2-5 illustrates embodiments of an implantable medical device having a safety unit arranged at different positions. Figure 2 schematically illustrates an implantable medical device 200 similar to the implantable medical device 110 of Figure 1.The safety unit 213 of figure 2 comprises a switch, and Figure 2 illustrates an alternative arrangement of the receiving coils 114a, 114b, ascompared to the implantable medical device 100 of Figure 1. Figure 2 illustrates an embodiment of receiving coils 114a, 114b. The receiving coils 114a, 114b of Figure 2 is interchangeable to,or may be used in combination with, the receiving coil 114 of Figure 1. The receiving coils 114a, 114b are connected in series, with a centertap in between. The receiving coils 114a, 114b may be two receiving coil parts of a receiving coil 114, with a center tap in between. The center tap of Figure 2 is connected to ground 122. The center tap may be connected to any other part of the implantable medical device200. The center tap may be placed on a receiving coil 114 to create the receiving coils 114a, 114b. The center tap may be placed so that theinductance of the receiving coils 114a, 114b are of the same size as each other. This may be done, for example, by positioning the centertap so that the electromagnetic properties of the receiving coils 114a, 114b are equivalent on either side of the center tap. This may bedone by, for example, positioning the center tap so that the receiving coils, or receiving coil portions, 114a, 114b have the same number ofwindings as each other. However, other electromagnetic properties, such as the material and the cross sectional area, of the receivingcoils 114a, 114b may also have an effect on the size of the inductance of the respective coil 114a, 114b. The receiving coil portions 114a, 114bmay have different electromagnetic properties than each other. Therefore, the receiving coils 114a, 114b may have different number ofwindings, and still have the same inductance as each other. The receiving coil, or receiving coil portions, 114a, 114b may have inductancesof different sizes, which may be due to the center tap being placed so that the parts of the receiving coils 114a, 114b have differentnumber of windings as compared to each other. The receiving coil portions 114a, 114b may have different inductances due to them havingdifferent electromagnetic properties than each other. The receiving circuit 116 may comprise a rectifier, and the type of the possiblerectifier may be decided in relation to the type of receiving coil 114a, 114b, to allow for a combination of rectifier and receiving coils 114a,114b that allows for the most optimum current provided to the energy consuming part 112.The safety unit 213 may initiate conduction or prohibit conduction. The safety unit 213 may comprise a switch 202. The safetyunit 213 may be configured to control the switch 202. The safety unit 213 may initiate conduction or prohibit conduction based on aparameter deviating from a predetermined range. The safety unit 213 may control the switch 202 based on a parameter deviating from apredetermined range, by, for example, switching the switch 202 between a conducting mode and a prohibiting mode. A conducting modeof the switch 202 may be equivalent to the switch 202 being turned on, and a prohibiting mode of the switch 202 may be equivalent tothe switch 202 being turned off. The parameter may be measured by the safety unit 213. The parameter deviating from a predeterminedvalue may comprise the parameter exceeding or falling under a threshold. The switch 202 may be arranged so that it can interrupt or allow a current flow between components of the implantablemedical device 200. Components of the implantable medical device 200 may include the impedance unit 118, the receiving circuit 116, andthe energy consuming part 112, as described above with reference to Figure 1. The switch 202 comprises two connection points. Eachconnection point may be connected to an electrical node of the implantable medical device 200. The switch 202 is configured control theelectrical connection between the two connection points. When the switch 202 is on, it is closed, and an electrical connection between the two connection points is established so that current can flow between the two connection points through the switch 202. When the switch 202 is off, it is open, and the electrical connection between the two connection points are broken so that current cannot flow through the switch 202 between the two connection points. In the embodiment shown in Fig.2, the switch 202 is positioned so that it can interrupt the current flow between the receivingunit 111 and the energy consuming part 112. More specifically, the switch 202 is positioned so that it can interrupt the current flowbetween the receiving circuit 116 and the energy consuming part 112. The switch 202 may switch off or switch on the electrical connection between the receiving unit 111 and the energy consuming part 112. The switch 202 has an initial state, which in the embodimentin Figure 2 is on. The switch 202 may be an active switch or a smart switch. The switch 202 may be controlled by a separate unit thatcontrols when to turn the switch on or off. As discussed above, the switch 202 may be switched if the transcutaneously transferredenergy poses a risk to the implantable medical device 200. The transcutaneously transferred energy may pose a risk if, for example, thefrequency of the transcutaneously transferred energy is at, or near, a resonance frequency of the receiving unit 111, and / or if themagnitude of the transcutaneously transferred energy is too high. Other influences than the transcutaneously transferred energy may cause the switch 202 to switch, such as, for example, parts of the implantable medical device 200 breaking, external heat influence, and / or a force being applied to the implantable medical device 200. Via the safety unit 213 of Figure 2, the energy consuming part 112 is disconnected from the receiving unit 111. Advantages ofdisconnecting the receiving unit and the energy consuming part 112 include that any current in the receiving unit 111 may be isolated fromthe energy consuming part 112. The safety unit 213 may thus protect the energy consuming part 112 from the transcutaneouslytransferred energy by controlling the switch 202. Disconnecting the energy consuming part 112 may decrease the probability of:overtemperatures, the patient being put at risk, and / or failure of the implantable medical device 200 causing the patient to requiringfurther surgery. Advantages of the safety unit 213 of Figure 2 may be similar to the advantages mentioned for the safety unit 113 ofFigure 1. Figure 3 schematically illustrates an implantable medical device 300 similar to the implantable medical device 200 of Figure2, wherein a safety unit 213 is arranged in another place than the safety unit 113 of Figure 1. The safety unit 213 of the implantable medicaldevice 300 of Figure 3 is positioned between the energy consuming part 112 and the ground 122. The initial state of the switch 202 of thesafety unit 213 of Figure 3 is on. Turning the switch 202 off disconnects the energy consuming part 112 from the ground 122.Disconnecting the energy consuming part 112 from the ground 122 decreases the current consumption of the energy consuming part 112.Decoupling may be done when the receiving unit 111 provides the energy consuming part 112 with more energy than the energy consuming part 112 is configured to handle. Decreasing the current consumption of the energy consuming part 112 may protect the energyconsuming part 112 from overvoltage and overcurrent. Further, the advantages for decoupling the energy consuming part 112 with theground 122 may include the advantages mentioned for decoupling the energy consuming part 112 from the receiving unit, presented withreference to Figure 2 above.Instead of decoupling the energy consuming part 112 from the receiving unit 111 and / or the ground 122, safety units 213 may bearranged on other parts of the implantable medical device 300. Examples of this will now be discussed with reference to Figures 4-5. Figure 4 schematically illustrates an implantable medical device 400, which is similar to the implantable medical device 200 ofFigure 2, and the implantable medical device 300 of Figure 3. The differences between the implantable medical device 400 of Figure 4 and the implantable medical device 200 of Figure 2, as well as the differences between the implantable medical device 400 of Figure 4and the implantable medical device 300 of Figure 3, include that the implantable medical device 400 of Figure 4 comprises one receivingcoil 114, comprises different electrical connections of the energy consuming part 112, and comprises a safety unit 413 comprising twoswitches 202a, 202b.The implantable medical device 400 of Figure 4 comprises one receiving coil 114. As described for Figure 1 and Figure 2, the implantable medical device may comprise any number of receiving coils 114 and the one receiving coil 114 of Figure 4 is interchangeable with the receiving coils 114a, 114b of Figure 2. The energy consuming part 112 of Figure 1-3 is connected to the ground 122. The energy consuming part 112 of Figure 4 isconnected to the receiving circuit 116. As described for Figure 1, the energy consuming part 112 may have two end portions connected tothe receiving circuit 116. The receiving circuit 116 may comprise a connection to the ground 122. Connecting two end portions of the energy consuming part 112 with the receiving circuit 116 may be interchangeable with connecting one end portion of the energy consuming part 112 with the receiving circuit and another end portion of the energy consuming part 112 with ground 122. Figure 4 illustrates a implantable medical device 400 comprising a safety unit 413 comprising two switches 202a, 202b. Thesafety unit may be similar to the safety units 113 and 213, as described above in reference to Figures 1, 2 and 3. The switches 202a, 202bmay be configured similarly to the switch 202 of Figure 2. The switches 202a, 202b of Figure 4 are arranged at a respective end portionof the impedance unit 118. The switches 202a, 202b may alternatively be connected over a part of the impedance unit 118. The initial stateof the switches 202a, 202b of Figure 4 are on. The switches 202a, 202b may be configured so that switching off both of the switches202a, 202b electrically disconnects at least parts of the impedance unit 118 from the other portions of the implantable medical device400. The safety unit may be configured to switch both of the switches 202a, 202b simultaneously. That is, the switches 202a, 202b mayboth be switched on and / or off at the same time, so that they are either both on or both off at the same time as each other. Theswitches 202a, 202b may be configured to switch dependently of the other. In this way, by switching off the switches 202a, 202b theimpedance unit 118 is electrically disconnected from the receiving coil 114 and the receiving circuit 116. As discussed above, the inductance of the receiving coil 114 and the impedance of the impedance unit 118 may contribute to a resonance frequency of the implantable medical device 400. Isolating the impedance unit 118 from the receiving coil 114 may cause theresonance frequency of the implantable medical device 400 to change and / or it may cause the resonance effect to decrease. Isolatingthe impedance unit 118 may thus lower the effectivity of the energy pickup. Isolating the impedance unit 118 may thus lower the amount ofenergy that is picked up by the implantable medical device 400. An isolated impedance unit 118 may allow energy to be supplied to theenergy consuming part 112. Isolating the impedance unit 118 may decrease the amount of energy transferred to the energy consumingpart 112. Advantages for decreasing the amount of energy that is received by the energy consuming part 112 may include the advantagesmentioned for decoupling the energy consuming part 112 from the receiving unit, presented with reference to Figure 1 and Figure 2 above.Again, isolating the impedance unit 118 may decrease the amount of energy transferred to the receiving circuit 116, which may protectthe receiving circuit from over energizing, overvoltage, overcurrent, overheating, and / or breaking. Figure 5 illustrates an implantable medical device 500, which is similar to the implantable medical device 200 of Figure 2, theimplantable medical device 300 of Figure 3, and the implantable medical device 400 of Figure 4. The implantable medical device 500 ofFigure 5 comprises receiving coils 114a, 114b similar to the receiving coils 114a, 114b of the implantable medical device 300 of Figure 3. Theenergy consuming part 112 of Figure 5 is connected to the receiving circuit 116 of Figure 5, similar to how the energy consuming part 112of Figure 4 is connected to the receiving circuit 116 of Figure 4. A feature illustrated in the implantable medical device 500, as comparedto the embodiments of the implantable medical devices 200, 300, 400 of Figure 2, 3, 4, respectively, is the positioning of the safety unit113. The safety unit 113 of Figure 5 is positioned between two end nodes of the two receiving coils 114a, 114b connected in series. Thesafety unit 113 may be configured to short circuit the receiving coils 114a, 114b. The initial state of the switch 202 of the safety unit 213 ofFigure 5 is off. Turning the switch 202 of the safety unit 213 short circuits the receiving coils 114a, 114b. Short circuiting the receiving coil114a, 114b decreases the energy transferred to the energy consuming part 112.The center tap may be positioned so that the two receiving coils, or receiving coil portions, 114a, 114b may have inductances ofthe same size as each other, as described in reference to Figure 2. The center tap being connected to ground 122 may allow thereceiving coils 114a, 114b to have antiparallel voltages. The antiparallel voltages of the receiving coils 114a, 114b may have, relative to theother receiving coil 114a, 114b, a voltage that is inverted. Inverted voltages may mean a phase shift of 180 degrees between them, so thatwhen one is positive the other is negative. Connecting these antiparallel voltages by switching on the switch 202 may lead to the voltagescancelling out, and there would then be no current output of the short-circuited receiving coils 114a, 114b. Advantages of short circuitingmay include that it minimizes the magnetic field intake and transformation to current of the receiving coils 114a, 114b. Another advantageof minimizing the magnetic field intake may include that some parts of the implantable medical device 500, such as the impedance unit 118, the receiving circuit 116, and the energy consuming part 112, may have very low or no energy transferred to them. By short circuiting the receiving coil 114a, 114b a minimum of transcutaneous energy may be picked up by of the receiving unit. Preferably, the shortcircuiting of the receiving coil 114a, 114b is configured to have no transcutaneously transferred energy reach the energy consuming part112, thus bringing the implantable medical device 500 to a safe state. A further advantage for decreasing the amount of energy receivedby the energy consuming part 112 may include the advantages mentioned for decoupling the energy consuming part 112 from the receivingunit, presented in Figure 2 above. Furthermore, a lower received energy may decrease the risk of damage to the components, such asthe impedance unit 118, the receiving circuit 116, and the energy consuming part 112. Damage to the components may occur due to, forexample, over energizing, overvoltage, overcurrent, overloading, overheating, or a combination thereof. Thus, the safety unit 113, 213, 413 of Figures 1-5 is configured to decrease the energy received by the energy consuming part116. In order to control the switches 202, 202a, 202b of the safety units 213, 415 of Figure 1-5, a controller for the switch may beimplemented. An example embodiment of this is illustrated in Figure 6.More details of the safety unit will now be described with reference to Figs.6-8. Any feature included in the safety unit described below may be included in any of the safety units in the embodiments described above, with reference to Figs.1-5. Figure 6 illustrates a system 600. The system 600 comprises an transmitting unit 102 similar to the transmitting unit 102 ofthe system 100 of Figure 1, but any transmitting unit described herein may be used. The system 600 further comprises a implantablemedical device 602similar to the implantable medical device 200 of Figure 1-5, described above. The safety unit 610 of the implantable medical device 600 may comprise a switch 202, such as have been discussed abovewith reference to Figs. 1-5. The safety unit 610 may further comprise second receiving coils, 614a, 614b. The second receiving coils 614a,614b are similar to the receiving coils 114a, 114b of Figures 2, 3, 5 and 6, as described above. The second receiving coils 614a, 614b doesnot have to be of the same type as the receiving coils 114a, 114b. For example, the implantable medical device 200 may have a receivingcoil 114, while the safety unit 610 may comprise two second receiving coils 614a, 614b, or the implantable medical device 200 maycomprise two receiving coils 114a, 114b, while the safety unit 600 has one second receiving coil 614. The implantable medical device 200may have a receiving coil 114 while the safety unit 600 has a second receiving coil 614, or the implantable medical device 200 may havetwo receiving coils 114a, 114b, while the safety unit 600 has two second receiving coils 614a, 614b. The second receiving coils 614a, 614b are configured to receive transcutaneously transferred energy. The second receiving coils 614a, 614b receive transcutaneously transferred energy from a transmitting unit 102. The second receiving coils 614a, 614b may be configured to receive transcutaneously transferred energy from the same transmitting unit 102 as the receiving coils 114a, 114b receivetranscutaneously transferred energy from. The safety unit 610 thus receive energy via the coils 114a, 114b.The safety unit 610 may further comprise a safety circuit 618. The safety circuit 618 is electrically connected to the secondreceiving coils 614a, 614b. The safety circuit 618 may comprise a circuit similar to the receiving circuit 116 described above. The safetyunit 610 may rectify current received from the second receiving coils 614a, 614b. The safety circuit 618 may be configured to control the switch 202to switch on or off. If more than one switch 202 iscomprised in the implantable medical device 602 or in the safety unit 610, the safety circuit 618 may control the more than one of theswitches 202. If the safety circuit 618 controls more than one switch 202, it may control the switches 202 independent or dependent on the other switches 202, or a combination wherein some switches 202 are controlled independently and some are controlled dependentlyof the others. The control circuit 618 may comprise an impedance unit, similar to the impedance unit 118 of the implantable medicaldevice 200. The safety unit 610 may comprise component such as, for example, a impedance, a rectifier, a voltage limitation device, avoltage limitation device, divider circuit, a latch circuit, a trigger.The safety circuit 618 may be configured to switch the switch 202 from an initial state. The safety circuit 618 may beconfigured to switch the switch 202 if the implantable medical device 602 is provided with more energy than the components of theimplantable medical device 602 are configured to handle. In some examples, the safety circuit 618 may switch the switch 202 when a parameter deviates from a predefined range. Theparameter may relate to a property of the implantable medical device 602 or the surrounding tissue. The parameter may, for example,relate to at least one of: temperature of the implantable medical device 602, temperature in the body of a patient, a voltage, a current, apower, an energy, a force, a pressure, or an insulation error. A parameter may be measured by a measuring device, and a parameterdeviating from a predefined range may be calculated by the safety circuit 618 by using the parameter obtained from the measuringdevice. The measuring device may be comprised in the implantable medical device 602. Alternatively, the measuring device may be external to the implantable medical device 602, and it may transmit data to the implantable medical device 602. A parameter deviating from a predefined range may be sensed by a fuse or circuit breaker being triggered, wherein the fuse and / or the circuit breaker is comprised in the safety circuit 618. The fuse may be an implantable or resettable fuse. In some examples,the fuse may have an automatic reset. The switch 202 may be switched from the initial state if a fuse or circuit breaker is triggered. Aparameter deviating from a predefined range may typically but not limited to be sensed by a diode or a semiconductor such as, forexample, a transient voltage suppression (TVS) Diode, Schottky diode, or Thyristor. The safety circuit 618 may be configured to switch the switch from an initial state based on multiple parameters. For example,the safety circuit 618 may be configured to switch the switch 202 from an initial state based on a second parameter. The secondparameter may be similar to the parameter, described above. The second parameter may relate to a different measurement than thefirst parameter. For example, the parameter may relate to temperature in the body of a patient, and the second parameter may relate toa current. The second parameter may be measured by the same measurement device that measures the parameter or by anotherdevice. The safety unit 610 may further be configured to reset the switch(es) 202 to the respective initial state. The safety unit 610may be configured to reset the switch(es) to an initial state when the implantable medical device 602 is disconnected from a power supply. In some examples, the safety unit 610 may be configured to reset the switch(es) 202 to the initial state on the condition that the components of the implantable medical device 602, such as the energy consuming part 112, are no longer at risk. The safety unit 610 may be configured to reset the switch(es) 202 on the condition that the transcutaneously transferred energy received by the safety unit 610 is below a threshold. The safety unit 610 may receive a proportional amount of transcutaneously transferred energy as compared to thetranscutaneously transferred energy received by the implantable medical device 200, or the transcutaneously transferred energyreceived by the safety unit 610 may be a fraction of the transcutaneously transferred energy received by the implantable medical device602. In some examples, the safety unit 610 may be configured to only receive sufficient energy for functioning when thetranscutaneously transferred energy is at levels that may pose a risk to the implantable medical device 602. Atransmitting unit 102 may transmit transcutaneously transferred energy to the implantable medical device 602 and thesafety unit 610. If the transcutaneously transferred energy becomes too high, the switch 202 can switch from an initial state in order toprotect the components of the implantable medical device 100. Once a transmitting unit 102 is removed or turned off, the transcutaneously transferred energy received by the implantable medical device 620 may reduce significantly. When thetranscutaneously transferred energy received by the implantable medical device 602 is sufficiently low, and / or zero, the components ofthe implantable medical device 200 may no longer be at a risk of, for example, over energizing, overcurrent, overvoltage, and / or overtemperature. When the transcutaneously transferred energy received by the implantable medical device 602 is low enough, the safety unit 610 may return the switch(es) 202 to an initial state. Low enough received energy could be when the received energy is belowa certain value, and / or when the received energy is zero. The switch 202 is preferably switched back to the initial state as soon as therisk of damaging the components of the implantable medical device 602 is over. Having the safety unit 610 depend on the transcutaneously transferred energy may mean that the safety unit 610 may notneed a separate power source. Using the same power source for both the energy receiver 111 and the second energy receiver 610 maybe a more reliable method of obtaining power when required, rather than utilizing separate power sources. The safety unit 610 may thusbe powered only when it is necessary, which may be when the transcutaneously transferred energy is high enough to risk damaging the components of the implantable medical device 602. The safety circuit 610 may switch the switch 202 to the initial state automatically when the risk of damaging the components is decreased, reducing the need of relying on another mechanism. Figure 7 illustrates a system 700. The system 700 comprises a transmitting unit 102 similar to the transmitting unit 102 of thesystem 100 of Figure 1. The system 700 of Figure 7 further comprises an implantable medical device 702 similar to the implantablemedical device 602 of Figure 6. Differences between the implantable medical device 702 of Figure 7 as compared to the implantable medical device 602 of Figure 6 include that the implantable medical device 700 is similar to the implantable medical device 500 and the implantable medical device 700 comprises an safety unit 710. The implantable medical device 700 of Figure 7 is similar to the implantable medical device 500 of Figure 5. The safety unit 710of Figure 7 is similar to the safety unit 610 of Figure 6. The safety unit 710 of Figure 7 comprises a safety circuit 718. The safety circuit718 of Figure 7 is similar to the safety circuit 618 of Figure 6. The safety circuit 718 of Figure 7 may have the same function as the safety circuit 618 of Figure 6. The safety circuit 718 of Figure 7 is illustrated with components. Components of the safety circuit 718 include arectifier 712, a voltage limitation device 704, and a safety portion 714. The combined functions of the components of the safety circuit 718are similar to the function of the safety circuit 618 of Figure 6. The safety circuit 718 may comprise a rectifier 712. The rectifier 712 may be similar to the receiving circuit 116 of any ofFigures 1-5. The safety circuit 718 may further comprise a safety portion 714, a voltage limitation device 704, and a connection to theground 122. The second receiving coils 614a, 614b is electrically connected to the rectifier 712. The rectifier 712 is electrically connectedto the safety portion 714 and the voltage limitation device 704. The safety portion 714 is electrically connected to the voltage limitationdevice 704. The safety portion 714 is electrically connected to the switch 202. The features of the rectifier 712 is similar to the rectifyingfunctions of the safety circuit 618 of Figure 6. The safety portion 714 of Figure 7 may control the switch 202 of Figure 7 similar to how the safety circuit 618 of figure 6 controls the switch 202 of Figure 6. The current received by the second receiving coils 614a, 614b is alternating, as illustrated by the first graph 720a, and thesecond graph 720b. The alternating current received by the second receiving coils 614a, 614b is transferred to the rectifier 712. Therectifier 712 rectifies the incoming current. The rectifier 712 outputs a rectified current, as illustrated by the third graph 720c. Thecurrent rectified by the rectifier 712 is transferred to the safety portion 714. The potential difference between the node comprising therectified current and the ground 112 creates a voltage difference over the voltage limitation device 704. The voltage limitation device maylimit the voltage level between two nodes, wherein one node may be the ground 122. A voltage limitation device 704 may, for example,limit the voltage across it by conducting when the voltage reaches a specific voltage threshold. The safety portion 714 is connected to thevoltage limitation device 704, so that the voltage limitation device 704 limits the voltage at the safety portion 714. The voltage over thevoltage limitation device 704 may power the safety portion 714. The optimal power for the safety portion 714 may be the voltage over thevoltage limitation device 704. The voltage limitation device 704 may, for example, comprise a Zener diode, a transient voltage suppression (or TVS) Diode, Schottky diode, Thyristor, or metal oxide varistors (MOVs). The voltage limitation device 704 may be a Zener diode that becomes reversebiased at the breakdown voltage of the Zener diode. The safety portion 714 may have the breakdown voltage of the Zener diode as thedriving voltage. The features of the safety portion 714 of Figure 7 is similar to the safety functions of the safety circuit 618 of Figure 6. Thesafety portion 714 may be configured to control the switch 202, similar to how the safety circuit 618 controls the switch 202 of Figure 6.The safety portion 714 of Figure 7 may be configured to switch the switch 202 from an initial state on the condition of one or moreparameters, similar to how the safety circuit 618 may switch the switch 202 of Figure 6 from an initial position on the condition of one ormore parameters. The safety portion 714 may be configured to reset the switch 202 to an initial state, similar to how the safety current618 resets the switch 202 of Figure 6 to an initial state.The safety portion 714 may comprise a latch circuit to control the state of the switch. A latch circuit may initially have theswitch 202 remain in an initial state until there is a risk of damage for the implantable medical device 702 (as may be measure by ameasuring device or as determined by, for example, a fuse or circuit breaker, as discussed above), at which point the latch circuit may cause the switch 202 to switch from an initial state. When the risk of damage for the implantable medical device 702 is alleviated, the latch circuit may cause the switch 202 to return to an initial state. The risk of damage for the implantable medical device 702 may be alleviated when amount of transcutaneously transferred energy is decreased sufficiently. When the amount of transcutaneouslytransferred energy is decreased sufficiently, the voltage over the voltage rectification 704 device may not be sufficient for powering thesafety portion 714. When the power of the safety portion 714 is not sufficient, it may cause the latch circuit comprised in the safety portion 714 to reset. When the latch circuit resets, the switch 202 may be reset to an initial state. The safety portion 714 may preferably switch the switch 202 from an initial state as quickly as possible at the risk of damage for the implantable medical device 702. The safetyportion 714 may preferably switch the switch 202 back to the initial state as quickly as possible when the risk of damage for theimplantable medical device 702 is alleviated. The latch circuit may be an active-high latch or an active low latch. The latch circuit remains in its first state unit an inputtriggers a change. The latch will serve as a memory and retains information as long as the power is on. Insufficient power to the latchcircuit will cause it to return to an first state. An advantages of utilizing a latch circuit is that it requires no power to keep its first state, so that it may not drain the internal energy of the implantable medical device 702. Furthermore, a latch circuit is kept in the state it is in while it has power, and it resets automatically when it loses power. Automatically resetting and keeping its states may contribute to the safety of the implantable medical device 702. It is to be understood that instead of a separate latch circuit and a separate switch 202, a latch switch may comprise the functions similar to the functions of a switch 202, as well as the functions of a latch circuit described herein, and may be used instead of, or in complement to, a latch circuit and / or a switch 202. The functions of the switch 202 may be integrated in the latch circuit. The functions of the switch 202 may be integrated in the safety portion 714. The safety circuit 718 may be configured so that external influences, other than sufficiently reduced amount of transcutaneously transferred energy, should not reset the switch 202 back to an initial state. The safety portion 714 may be configured so that external influences, other than sufficiently reduced amount of transcutaneously transferred energy, should not reset the switch 202 back to an initial state. More precisely, a latch circuit comprised in the safety portion 714 may be configured so that external influences, other than sufficiently reduced amount of transcutaneously transferred energy, should not reset the switch 202 back to an initial state. If only a sufficiently reduced amount of transcutaneously transferred energy may cause the switch 202 to return to the initial state, then the switch 202 may not be able to reset if there is still a risk for the implantable medical device 702 and / or the patient. Being unable to reset the switch 202 until the risk of danger (for the implantable medical device 702 and / or the user) is alleviated may increase the safety of the implantable medical device 702. External influences, other than sufficiently reduced amount of transcutaneously transferred energy, not being able to affect the switch 202 may increase the safety of the implantable medical device 702. Figure 8 illustrates a safety unit 810 for use, for example, in any of the above described embodiments. The safety unit 810 maycomprise a second receiving coil 614 for receiving transcutaneously transferred energy, similar to the second receiving coils 614a, 614bof Figure 6, and similar to the second receiving coils 614a, 614b of Figure 7. As mentioned above, one second receiving coil 614 may beinterchangeable to two second receiving coils 614a, 614b. The safety unit 810 may comprise a switch 202.The safety unit 810 comprises a safety circuit 818. The safety circuit 818 may have similar functions to the safety circuit 618of Figure 6, and / or the safety circuit 718 of Figure 7. The safety circuit 818 may comprise a first safety portion 814 and a second safetyportion 816. The safety circuit 816 may further comprise a connection to the ground 122. In some examples, the safety circuit 816 mayfurther comprise a measurement unit 820.The safety circuit 818 of Figure 8 may comprise a rectifier 812. The second receiving coil 614 is electrically connected to therectifier 812. The rectifier 812 is electrically connected to the first safety portion 814 and the second safety portion 816. The first safetyportion 814 is electrically connected to the second safety portion 816 and electrically connected to the measurement unit 820. The firstsafety portion 814 is electrically connected to the switch 202. The switch 202 may be integrated in the first safety portion 814. The second safety portion 816 is electrically connected to ground 122. The rectifier 812 of Figure 8 may be similar to the rectifier 712 of Figure 7. The rectifier 812 may be configured to receivealternating power, as illustrated by the first graph 720a, and the second graph 720b. The rectifier 812 may rectify an incoming current.The rectifier 812 may be configured for transmitting a rectified current, as illustrated by the third graph 720c. The rectifier may beconfigured to power the first latch circuit 814 and the second latch circuit 816.The measurement unit 820 may be configured to measure a parameter. The parameter may be similar to the parameter or parameters used by the safety circuit 618 of Figure 6, mentioned above.The first safety portion 814 of Figure 8 may be similar to the safety portion 714 of Figure 7. The first safety portion 814 may getpower from the rectifier 812. The first safety portion 814 may be configured to control the switch 202. The first safety portion 814 may be configured to control the switch 202 based on one or more parameters. The first safety portion 814 may obtain the one or moreparameters from the measurement unit 820. The first safety portion 814 may comprise a latch circuit to control the state of the switch202, as described for the safety portion 714 of Figure 7. The first safety portion 814 may switch the switch 202 from an initial state whenthe parameter obtained from the measurement unit 820 is deviating from a predetermined range. The measurement unit 820 maydetermine when a parameter is deviating from a predetermined range and the first safety portion 814 may switch the switch 202 froman initial state based on the data received from the measurement unit 820. Each parameter measured by the measurement unit 820may individually, or in combination, cause the switch 202 to switch. The second safety portion 816 may comprise a voltage divider circuit. The second safety portion 816 may comprise a voltage limitation device, such as the voltage limitation device 704 of Figure 7. The second safety portion 816 may comprise a second latchcircuit. A second latch circuit may prevent a latch circuit of the first safety portion 814 from switching back the switch 202 to an initialstate after the switch 202 have switched from the initial state. A second latch circuit may return to a first state when it does not receivesufficient power. If a second latch circuit returns to a first state, it may stop preventing the latch circuit of the first safety portion 814 toswitch the switch 202 to an initial state. A first latch circuit and a second latch circuit may return to their respective first states whenthey receive insufficient amounts of transcutaneously transferred energy. A second latch circuit may prevent the first latch circuit fromreturning to a first state unless the transcutaneously transferred energy is below a threshold. A second latch circuit may act as abackup for the first latch circuit. Having a second latch circuit act as a backup to the first latch circuit may increase the safety of theimplantable medical device. While the present disclosure is susceptible to various modifications and alternative forms, specific embodiments are shownand described above by way of example in relation to the drawings, with a view to clearly explaining the various advantageous aspects ofthe present disclosure. It should be understood, however, that the detailed description herein and the drawings attached hereto are not intended to limit the disclosure to the particular form disclosed. Rather, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the following claims. Itemized list of examples 1. An implantable medical device comprising: an energy consuming part; a receiving unit comprising at least one coil configured for receiving transcutaneously transferred energy and transferring the received energy to the energy consuming part; a switch placed between a first point an a second point for switching off or switching on the electrical connection between the first point and the second point; and a safety unit, wherein: the safety unit is configured to control the switch for switching off or switching on the electrical connection between the first point and the second point based on a parameter deviating from a predetermined range, wherein at least one of the following: the first point is the receiving unit and the second point is the energy consuming part; the first point is the energy consuming part and the second point is a ground; the first point is a first end portion of the coil and the second point is a second end potion of the coil; or the receiving unit comprises an impedance electrically connected to the coil, the first switch is arranged at a first end portion of the impedance, and a second switch is arranged at a second end portion of the impedance, such that the impedance can be electrically disconnected from the other portions of the implantable medical device. 2. An implantable medical device comprising: an energy consuming part; a receiving unit comprising at least one coil configured for receiving transcutaneously transferred energy and transferring the received energy to the energy consuming part; afirst switch arranged between the receiving unit and the energy consuming part for switching off the electricalconnection between the receiving unit and the energy consuming part; and a safety unit configured to control the first switch for switching off the electrical connection between the receiving unit and the energy consuming part based on a parameter deviating from a predetermined range. 3. An implantable medical device comprising: an energy consuming part; a receiving unit comprising at least one coil configured for receiving transcutaneously transferred energy and transferring the received energy to the energy consuming part; afirst switch arranged between the energy consuming part and a ground for switching off the electrical connectionbetween the energy consuming part and the ground; and a safety unit configured to control the first switch for switching off the electrical connection between the energyconsuming part and the ground based on a parameter deviating from a predetermined range.4. An implantable medical device comprising: an energy consuming part; a receiving unit comprising at least one coil configured for receiving transcutaneously transferred energy and transferring the received energy to the energy consuming part, the receiving unit comprising an impedance unit configured to be electrically connected to the coil; a first switch arranged at a first end portion of the impedance and a second switch arranged at a second end portion of the impedance unit, such that the impedance unit is electrically disconnected from the other portions of the implantable medical device when the first and / or the second switches are open; and a safety unit configured to control the first switch and the second switch based on a parameter deviating from a predetermined range.5. The implantable medical device according to example 4, wherein the first switch and the second switch are interconnected such thatthey operate concurrently. 6. An implantable medical device comprising: an energy consuming part; a receiving unit comprising at least one coil configured for receiving transcutaneously transferred energy and transferring the received energy to the energy consuming part; a first switch connected to a first end portion of the coil and a second end portion of the coil; and a safety unit configured to control the first switch for switching on the electrical connection between the first end portion of the coil and the second end portion of the coil based on a parameter deviating from a predetermined range.7. The implantable medical device according to any one of example 1-5, wherein an initial state of the first switch is on, and / or the initialstate of the second switch is on.8. The implantable medical device according to any one of example 1 or 6, wherein an initial state of the first switch is off.9. The implantable medical device according to any one of example 7-8, wherein the safety unit is configured to reset the first switchand / or the second switch to the initial state on the condition that the transcutaneously transferred energy received by the safety unit is below a threshold.10. An implantable medical device according to any one of example 7-9, wherein the first switch and / or the second switch is reset to theinitial state if the safety unit is disconnected from a power supply.11. The implantable medical device according to any one of example 7-10, wherein the safety unit comprises a fuse or circuit breaker that,if triggered, causes the first switch and / or the second switch to switch off or switch on, so that the switch is no longer in the initial condition.12. The implantable medical device according to example 11, wherein the fuse or the circuit breaker is triggered by the parameterexceeding a threshold. 13. The implantable medical device according to any one of the preceding examples, wherein the parameter is related to at least one of: temperature of the medical device, temperature in the body of a patient, a voltage, a current, a power, an energy, a force, a pressure, or an insulation error. 14. The implantable medical device according to any one of the preceding examples, wherein the safety unit comprises: a measurement unit configured to measure the parameter; and a controller configured to control the first switch or the second switch in response to the parameter deviating from a predefined allowed range of the parameter. 15. The implantable medical device according to any of the preceding examples, wherein the safety unit comprises a first latch circuit configured to control the first switch and / or the second switch.16. The implantable medical device according to example 15, wherein the first latch circuit is connected to a voltage limitation device tokeep the energy supply of the latch circuitry active. 17. The implantable medical device according to any one of the preceding examples, wherein the safety unit comprises a second receiving unit comprising at least one coil configured for receiving the transcutaneously transferred energy for powering the safety unit.18. The implantable medical device according to example 17, wherein the safety unit is configured to return the first switch and / or thesecond switch to an initial position on condition that the second receiving unit stops receiving transcutaneously transferred energy.19. The implantable medical device according to example 14, wherein the measurement unit is configured to measure a secondparameter, different from the parameter.20. The implantable medical device according to example 19, wherein the second parameter is related to at least one of: a temperatureof the medical device, a temperature in the body of a patient, a voltage, a current, a power, an energy, a force, a pressure, or aninsulation error.21. The implantable medical device according to example 19 or 20, wherein the controller is configured to control the first switch and / orthe second switch in response to the second parameter deviating from a predefined allowed range of the parameter. 22. The implantable medical device according to any one of the preceding examples, wherein the receiving unit is configured to rectify an incoming alternating current. 23. The implantable medical device according to any one of the preceding examples, wherein the energy consuming part of the implantable medical device is configured for storing energy received by the receiving unit. 24. The implantable medical device according to any one of the preceding examples, wherein the energy consuming part of the implantable medical device is configured to exert a force on a body portion of the patient. 25. The implantable medical device according to any one of the preceding examples, wherein the energy consuming part of the implantable medical device comprises an electrical motor and wherein the safety unit is configured for controlling the electrical motor.

Claims

CLAIMS 1. An implantable medical device comprising: an energy consuming part;a receiving unit comprising at least one coil configured for receiving transcutaneously transferred energy and transferring the received energy to the energy consuming part; a switch placed between a first point an a second point for switching off or switching on the electrical connection between the first point and the second point; and a safety unit, wherein: the safety unit is configured to control the switch for switching off or switching on the electrical connection between the first point and the second point based on a parameter deviating from a predetermined range, wherein at least one of the following: the first point is the receiving unit and the second point is the energy consuming part; the first point is the energy consuming part and the second point is a ground; the first point is a first end portion of the coil and the second point is a second end potion of the coil; or the receiving unit comprises an impedance electrically connected to the coil, the first switch is arranged at a first end portion of the impedance, and a second switch is arranged at a second end portion of the impedance, such that the impedance can be electrically disconnected from the other portions of the implantable medical device.

2. The implantable medical device according claim 1, wherein an initial state of the first switch is on, and / or the initial state of the second switch is on.

3. The implantable medical device according to any one of claims 1 or 2, wherein an initial state of the first switch is off.

4. The implantable medical device according to any one of claims 2-3, wherein the safety unit is configured to reset the first switch and / or the second switch to the initial state on the condition that the transcutaneously transferred energy received by the safety unit is below a threshold.

5. An implantable medical device according to any one of claims 2-4, wherein the first switch and / or the second switch is reset to the initial state if the safety unit is disconnected from a power supply.

6. The implantable medical device according to any one of claims 2-5, wherein the safety unit comprises a fuse or circuit breaker that, if triggered, causes the first switch and / or the second switch to switch off or switch on, so that the switch is no longer in the initial condition.

7. The implantable medical device according to claim 6, wherein the fuse or the circuit breaker is triggered by the parameter exceeding a threshold.

8. The implantable medical device according to any one of the preceding claims, wherein the parameter is related to at least one of:temperature of the medical device, temperature in the body of a patient, a voltage, a current, a power, an energy, a force, a pressure, oran insulation error.

9. The implantable medical device according to any one of the preceding claims, wherein the safety unit comprises: a measurement unitconfigured to measure the parameter; and a controller configured to control the first switch or the second switch in response to theparameter deviating from a predefined allowed range of the parameter.

10. The implantable medical device according to any of the preceding claims, wherein the safety unit comprises a first latch circuit configured to control the first switch and / or the second switch.

11. The implantable medical device according to claim 10, wherein the first latch circuit is connected to a voltage limitation device to keep the energy supply of the latch circuitry active.

12. The implantable medical device according to any one of the preceding claims, wherein the safety unit comprises a second receivingunit comprising at least one coil configured for receiving the transcutaneously transferred energy for powering the safety unit.

13. The implantable medical device according to claim 12, wherein the safety unit is configured to return the first switch and / or thesecond switch to an initial position on condition that the second receiving unit stops receiving transcutaneously transferred energy.

14. The implantable medical device according to claim 9, wherein the measurement unit is configured to measure a second parameter, different from the parameter.

15. The implantable medical device according to claim 14, wherein the second parameter is related to at least one of: a temperature of the medical device, a temperature in the body of a patient, a voltage, a current, a power, an energy, a force, a pressure, or an insulation error.

16. The implantable medical device according to claim 14 or 15, wherein the controller is configured to control the first switch and / or thesecond switch in response to the second parameter deviating from a predefined allowed range of the parameter.

17. The implantable medical device according to any one of the preceding claims, wherein the receiving unit is configured to rectify an incoming alternating current.

18. The implantable medical device according to any one of the preceding claims, wherein the energy consuming part of the implantable medical device is configured for storing energy received by the receiving unit.

19. The implantable medical device according to any one of the preceding claims, wherein the energy consuming part of the implantable medical device is configured to exert a force on a body portion of the patient.

20. The implantable medical device according to any one of the preceding claims, wherein the energy consuming part of the implantablemedical device comprises an electrical motor and wherein the safety unit is configured for controlling the electrical motor.

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