Electrical circuit arrangement for biomedical interface

Abstract

An electrical circuit arrangement for a biomedical interface is described, the electrical circuit arrangement comprising n electrical contacts used to contact at least one embedded electrode arrangement that can be attached to an organic structure, and at least one electrical functional block electrically connected to at least one of the n electrical contacts. The invention is characterized in that at least one electrical function has a functional element realized by means of SOI technology. The at least one electrical functional block can be operated with a supply voltage that can assign an average potential, the supply voltage corresponding to the potential that can be assigned to the organic structure.

Description

[Technical Field]

[0001] The present invention relates to an electrical circuitry for a biomedical interface, the electrical circuitry having n electrical contacts, where the n electrical contacts are used to contact at least one implantable electrode arrangement that can be attached to an organic structure, and at least one electrical function block electrically connected to at least one of the n electrical contacts. [Background technology]

[0002] Functional electrical stimulation or neurostimulation (FES / FNS) is a method of treating various types of neurological dysfunction through the stimulation of nerves with an electrical charge. Applications range from cardiac pacemakers and retinal implants to peripheral nerve stimulators.

[0003] Implantable electronic devices designed for and used within the body for FES / FNS typically contain multiple functional switching areas known as function blocks (FBs), which are used for, for example, energy management, monitoring and / or control, data storage, charge balancing, voltage conversion (level shifting), and detection and active stimulation of neuronal signals.

[0004] Related circuit concepts for neural stimulator design and operation are described in the paper by A. Taschwer et al., “A Charge Balanced Neural Stimulator with 3.3V to 49V Supply Compliance and Arbitrary Programmable Current Pulse Shapes,” 2018 IEEE Biomedical Circuits and Systems Conference (BioCAS), Cleveland, OH, USA, 2018, pp. 1–4, doi: 10.1109 / BIOCAS.2018.8584755.

[0005] The functional blocks used for detecting neural signals as well as stimuli are electrically connected directly to the organic structure via at least one electrode or electrode array individually adapted to the organic structure. In this regard, a known implantable electrode configuration used for site-selective recording of neuroelectric signals propagating along at least one nerve fiber as well as for selective stimulation of at least one nerve fiber is disclosed in EP 3204105 B1.

[0006] The most important requirement for any neurostimulator is patient safety, i.e., the level of electrical simulation applied to at least one organic structure must be organically tolerable, and measures must be taken to ensure patient protection in the event of a failure within the electrical circuitry inherent in the implanted electronic device.

[0007]

[0005] Document DE19951491A1 discloses a medical device comprising a first digital signal processing system receiving at least one first analog input, the first digital signal processing system having a first digital signal processor processing data at least representative of the first analog input at a first clock frequency to perform at least one first function within a specified time period.

[0006] Furthermore, a second digital signal processing system receiving at least one second analog input, the second digital signal processing system having a second digital signal processor processing data at least representative of the second analog input at a second clock frequency to perform at least one second function within a specified time period. Each of the first and second digital processing systems is constructed from a type of circuit selected from the group consisting of CMOS circuits, CML circuits, SOS circuits, SOI circuits, BICMOS circuits, PMOS circuits, and NMOS circuits.

[0008] U.S. Patent Application Publication No. 2014 / 0200626 discloses an implantable transient neurostimulation device for stimulating target tissue within a patient's body, the device including a substrate configured to communicate wirelessly with a control device located outside the patient's body and configured to stimulate the target tissue, the substrate and circuitry being surrounded by a material configured to degrade within the patient's body.

[0009] EP 2446921B1 describes a circuit for selecting multiple electrodes in an implantable electrode device, which includes a signal interface with multiple electrodes and signal connections, and switching electronics with programmable switches, each designed as a MOS transistor with a charge storage. Summary of the Invention

[0010] The present invention is based on the problem of further developing an electronic circuit arrangement for a biomedical interface having n electrical contacts, where n electrical contacts are used to contact at least one implantable electrode arrangement that can be attached to an organic structure, and having at least one electrical functional block electrically connected to at least one of the n contacts, so that risks to the patient in the event of a possible failure during operation of a medically active implant that includes the electrical circuit arrangement are avoided or at least significantly reduced.

[0011] The solution to the problem forming the basis of the present invention is set out in claim 1. Features that further develop the inventive concept form the subject matter of the dependent claims and can be found in the further description, in particular with reference to the drawings.

[0012] According to this solution, an electrical circuit arrangement for a biomedical interface having the features of the preamble of claim 1 is characterized in that at least one electrical functional block has functional elements implemented by means of SOI technology, i.e. "silicon on insulator", and that at least one electrical functional block is capable of operating with a supply voltage that can assign an average potential, said supply voltage corresponding to the potential that can be assigned to the organic structure.

[0013] Each of the n electrical contacts, directly or indirectly connected to the organic structure for purposes such as stimulating and / or detecting neural signals, is also connected to at least one electrical function block of an electrical circuit configuration that is part of an implantable medical device, e.g., in the form of a neural stimulator. Each individual electrical function block, e.g., required for measuring and detecting neural signals, generating stimulation signals, controlling individual or all of the function blocks, etc., is individually configured for a different supply voltage. In conventional circuit configurations, i.e., using bulk CMOS semiconductor technology, the supply voltages are only positive potentials. Combining or linking these individual supply voltages on a joint circuit output or circuit input can result in surges and destructive effects, especially in the event of a fault condition.

[0014] The electrical circuit arrangement according to the present invention utilizes the advantages of SOI technology, in that circuit elements are dielectrically isolated, thereby reducing excess capacitance and enabling faster switching speeds, but with lower power consumption than conventional circuit arrangements. More specifically, SOI technology allows the use of positive and negative supply potentials, so that individual electrical functional blocks can operate with supply voltages whose voltage ranges are limited by a minimum negative voltage value and a maximum positive voltage value, rather than operating only at positive voltages including zero volts as in the past. This allows the selection of the smallest possible voltage value, i.e., an average potential slightly away from or characterized by zero volts. Preferably, the average potentials of all electrical functional blocks in the electrical circuit arrangement are selected to be the same.

[0015] The electrical circuit arrangement is part of a medical and / or functional implant, preferably an active medical implant, whose electrical contacts are connected to the endogenous organic structures by appropriately assembled electrodes, so that the average potential of the supply voltages of all electrical functional blocks is selected according to the organic potential of the body. In this way, it is guaranteed that in the event of a malfunction or a required switching process in the electrical circuit arrangement, no electrical load or stimulation acts on the organic structures.

[0016] A voltage source in the form of a floating voltage source is used to provide the supply voltages for all electrical functional blocks of the electrical circuit arrangement, which is preferably configured as an ASIC circuit. The floating voltage source can be designed as an integral part of the circuit arrangement or as a separate component and connected to the circuit arrangement by at least one electrical contact. Regardless of the location and design of the voltage source relative to the circuit arrangement, the voltage source must be galvanically isolated from all organic structures.

[0017] Depending on the type and function of the medically active implant, the electrical circuit arrangement must be assembled accordingly and fitted with the respectively required electrical functional blocks, whose assignable functions can correspond to one of the following functional possibilities: Generation of voltage or current controlled stimulus signals, Biomarkers, especially electrical biosignal detection, Voltammetry, amperometry, Control of electromechanical components, Energy harvesting by means of piezoelectric, thermoelectric and / or electrochemical transducer elements, Measurement and monitoring of the supply voltages and electrical connections of at least two function blocks; Signal output for external signal processing.

[0018] The individual functional blocks are structured and arranged exclusively using components implemented by means of SOI technology, preferably in the form of CMOS transistors or optical components. [Brief explanation of the drawings]

[0019] The invention will now be described by way of example, without limiting the general inventive concept, by way of example of embodiments, with reference to the drawings, in which: [Figure 1] FIG. 1 shows a block diagram of implantable electrical circuitry for controlling neural stimulation electrodes. [Figure 2] 1 shows the supply voltages of the different electrical function blocks. DETAILED DESCRIPTION OF THE INVENTION

[0020] FIG. 1 shows a schematic block circuit diagram of electrical circuitry 2 designed for an active medical implant 1, used for example for neurostimulation of the vagus nerve.

[0021] The electrical switch device 2 is realized in the form of an application specific integrated circuit (ASIC) on a chip 3, i.e., an ASIC chip, and comprises a number of different electrical functional blocks F1, F2, F3, ..., which have only functional elements implemented by means of SOI technology, preferably in the form of CMOS transistors or optical components. Depending on the type and function of the medical implant, the selection and arrangement of the different electrical functional blocks F1, ..., Fn, as well as their interconnections on the chip 3, must be appropriately coordinated with one another.

[0022] The electrical contacts 4 of the electrical circuit arrangement 2 are used, of which n electrical contacts 4 are used to contact at least one implantable electrode arrangement 6, which can be attached to an organic structure 5. In the example shown in FIG. 1, it is assumed that the electrode arrangement 6 is designed as a wrap sleeve or cuff electrode arrangement and is attached around the vagus nerve as the organic structure 5. This type of electrode device 6, designed as a wrap sleeve, is disclosed, for example, in EP 3204105 B1. The n electrical contacts 4 are connected to the electrode device 6 via a conductor arrangement 7.

[0023] At the same time, the n electrical contacts 4 of the electrical circuit arrangement 2 are connected to at least one of the electrical function blocks F1, F2, . . . , Fn, which are connected to one another according to a predetermined circuit diagram.

[0024] The n electrical contacts 4 connected to both at least one electrical functional block F1,...,Fn and at least one electrode 6' of the electrode configuration 6 are each configured for the maximum supply voltage of the electrical functional blocks F1,...,Fn attached to the chip 2. Each of the n electrical contacts 4 can contact one electrical functional block or multiple electrical functional blocks in the chip 3.

[0025] For example, an electrical energy source, preferably designed as a floating voltage source, as well as a function block configured for voltage monitoring, e.g., F1, can be connected to one and the same electrical contact or contact pair 4, to which a maximum supply voltage of +18 volts is tapped or applied. An electrical function block, e.g., F2, used as a precision measurement circuit operating with a supply voltage of +0.9 volts, can be connected to a further electrical contact 4 or contact pair. Furthermore, different supply voltages, each matched to the function of the electrical function block Fn, can be applied to the corresponding further contact 4. Common to all the different supply voltages is their common reference or average potential M, which in the above example is chosen as 0 V.

[0026] The supply voltages of the electrical functional blocks F1, F2, F3 are shown in the voltage diagram shown in Figure 2. It is clear that the supply voltages of all the electrical functional blocks may be of different magnitudes, but all have the same mean potential M, which preferably corresponds to the organic rest potential.

[0027] This allows various simultaneous combinations and new interconnections to be realized between the individual electrical functional blocks F1, F2, ...; Fn and the electrical contacts 4. In particular, in the rest state of the chip 3, the same reference or average potential (in this case 0 volts) is always applied to the electrical contacts 4 and therefore also to the electrical electrodes 6' in contact with the organic structures 5. Of course, it is also possible to set an average potential M diverging from 0 volts depending on the organic potential to which the electrodes 6' are connected.

[0028] In this way, different potentials on the electrical contacts 4 that would lead to direct currents between the individual contacts 4 are prevented.

[0029] Since different resting potentials do not occur between the electrical contacts, constant DC currents are avoided. Furthermore, even when new functions are interconnected, rapid potential changes do not occur at the electrode contacts. Furthermore, destructive effects at the node points of the various electrical function blocks are reduced and the so-called latch-up effect can be completely eliminated. [Explanation of symbols]

[0030] 1. Medical implants 2 Electrical circuit devices 3 chips 4 Electrical contacts 5 Organic structure 6. Electrode device, cuff electrode 6' electrode 7 Conductor Device

Claims

1. 1. An electrical circuit arrangement for a biomedical interface, comprising: the electrical circuit device has electrical contacts, n of which are used to contact at least one embeddable electrode arrangement that can be attached to an organic structure; the electrical circuit device further includes at least one electrical function block electrically connected to at least one of the n electrical contacts; the at least one electrical functional block has a functional element implemented by SOI technology; the at least one electrical functional block can be operated with a supply voltage that can assign an average potential, the supply voltage corresponding to a potential that can be assigned to the organic structure; Electrical circuit device.

2. 2. The electric circuit arrangement according to claim 1, wherein said electric circuit arrangement is designed in the form of an integrated circuit, more particularly in the form of an ASIC circuit.

3. 3. The electrical circuit arrangement of claim 1 or 2, wherein the electrical circuitry is part of a medical and / or functional implant.

4. The electrical circuit device of claim 3 , wherein the medical implant is an active medical implant.

5. The electrical circuit device of claim 4 , wherein the active medical implant is used for neurostimulation or neuromodulation.

6. 6. An electric circuit arrangement according to claim 1, wherein the supply voltage originates from a voltage source designed in the form of a floating voltage source arranged and configured in galvanic isolation from the organic structure.

7. 7. The electric circuit arrangement according to claim 6, wherein the voltage source is designed and arranged as an integral component of the electric circuit arrangement.

8. 7. The electric circuit arrangement according to claim 6, wherein the voltage source is designed as a separate component from the electric circuit arrangement and is connected to the electric circuit arrangement via at least one of the electrical contacts.

9. - generation of voltage or current controlled stimulus signals; - detection of biomarkers, especially electrical biosignals; Voltammetry, amperometry, - Control of electromechanical components, - Energy harvesting using piezoelectric and thermoelectric - measuring and monitoring supply voltages, - an electrical connection of at least two functional blocks; - signal output for external signal processing, At least one of the following can be assigned to the at least one electrical function block:

9. The electric circuit device according to claim 1.

10. 10. An electric circuit arrangement according to any one of claims 1 to 9, wherein the functional elements implemented by means of SOI technology are at least one of the following: transistors, optical components.

11. the electrode attachable to the organic structure is part of a cuff electrode; the organic structure of the vagus nerve is a living organism; 11. The electric circuit device according to claim 1.

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