Electronic circuit for magnetic neurostimulation and associated control system

Abstract

Device for generating short current pulses by means of an electronic circuit with at least two electrical switches and with at least one electrical energy storage device, wherein the device comprises at least: an electronic control unit (901, 1001, 1101, 1201, 1301, 1401) configured to send electrical signals to control the at least two electrical switches, which are to be transmitted as coded electrical signals via an electrical signal transmission line (904, 906, 1004, 1006, 1104, 1106, 1107, 1204, 1213, 1214, 1206, 1302, 1306, 1404) to at least one decoder (907, 1005, 1108, 1207, 1307, 1407), which is to be controlled by the at least one decoder (907, 1005, 1108, 1207, 1307, 1407), which is configured to decode the coded electrical signals into respective switch control signals describing a switch state to be set for one of the at least two switches,wherein the respective switch control signals, when implemented at the respective at least two switches, are such that current pulses with a total duration of less than five milliseconds are provided at an output of the electronic circuit for the excitation of at least one stimulation coil (101, 201, 305), so that the at least one stimulation coil, when excited with these current pulses, generates magnetic field pulses with a magnetic flux density of 0.1 to 10 Tesla, which, according to the principle of electromagnetic induction, induce electrical currents in body tissue, which, through stimulation, trigger at least one action potential of nerve and / or muscle cells.

Description

[0001] The invention relates to the generation of stimulation pulses for inductive neuron stimulation, in particular to circuits for generating magnetic stimulation pulses and their control, including for peripheral and transcranial magnetic stimulation (TMS). State of the art

[0002] Magnetic stimulation, in which specific cells in body tissue are stimulated by externally applied electromagnetic fields, primarily neurons (e.g., in nerves) and muscle cells, is considered the only currently available painless, non-invasive method for stimulating neurons in a patient's brain. In recent years, it has also found increasing applications in the periphery of the nervous system, for example, in medical rehabilitation, diagnosis, research into the nervous system, and the often transsynaptic interaction of peripheral and central nervous system signals.

[0003] Magnetic stimulation is typically based on the principle of magnetic induction. A movable or fixed conductor coil, the so-called stimulation coil, is placed near a subject, patient, or animal to be stimulated and a time-varying current flows through it, creating a correspondingly time-varying magnetic field that penetrates the tissue to be stimulated and induces electrical fields within it. These fields, and the currents they generate, in turn stimulate neurons, muscle cells, and other excitable structures. State-of-the-art stimulation coils are designed to particularly well meet specific stimulation requirements, including, for example, penetration depth, a particularly high focality of stimulation through spatial concentration of the induced fields, or targeted stimulation of multiple targets or areas [Z.-D. Deng, SH Lisanby, AV Peterchev (2013).Electric field depth-focality tradeoff in transcranial magnetic stimulation: Simulation comparison of 50 coil designs. Brain Stimulation, 6(1):1-13.]. One advantage of inductive magnetic stimulation is its non-contact nature, as fields can be induced into the target tissue even over a certain spatial distance. Furthermore, unlike electrical stimulation via electrodes, the procedure is almost completely painless, since high current densities are avoided in areas with high nociceptor density, such as the skin. For these reasons, the method is also well-suited for stimulating deep tissue structures, e.g., the cerebral cortex through the skull, as well as for painless muscle stimulation.

[0004] In addition to delivering individual signals to neurons, muscle cells, or other excitable structures in the body, magnetic stimulation also enables neuromodulation. Using specific protocols, usually particular pulse rhythms, the excitability of neural networks can be selectively altered. Neuromodulation is currently one of the most important applications of magnetic stimulation in medicine and research. However, the neuromodulatory effect sizes achievable with conventional devices are very weak. This limited effect size of neuromodulation with magnetic pulses is a key challenge for the medical application of magnetic stimulation.

[0005] Although the potential fluctuations at the neuronal membrane required for stimulation are only a few millivolts, currently available stimulation devices still require pulse power in the megawatt range, generating heat of up to several kilowatts. During pulsed operation, the stimulation coil typically heats up so much that the application time is often limited to just a few minutes.

[0006] A highly effective method for increasing energy efficiency and reducing heat generation is discussed in the scientific literature [SM Goetz, NC Truong, MG Gerhofer, AV Peterchev, H.-G. Herzog, T. Weyh (2012). Optimization of magnetic neurostimulation waveforms for minimum power loss. Proc. IEEE EMBC 2012:4652-4656; SM Goetz, CN Truong, M. Gerhofer, AV Peterchev, H.-G. Herzog, T. Weyh (2013). Analysis and Optimization of Pulse Dynamics for Magnetic Stimulation. PLOS ONE 8(3):e55771.]. In contrast to sinusoidal current waveforms of the pulse in the stimulation coil, so-called pulse waveforms, novel, correspondingly optimized current waveforms are proposed for inducing the stimulating fields.

[0007] Ebenso wurden deutlich stärker neuromodulierende Pulsformen ermittelt und experimentell bestätigt [S. M. Goetz, B. Luber, S. H. Lisanby, C. I. Kozyrkov, W. M. Grill, and A. V. Peterchev (2013). Enhancement of rTMS neuromodulatory effects with novel waveforms demonstrated via controllable pulse parameter TMS (cTMS). 52nd Meeting of the American College of Neuropsychopharmacology, Hollywood, FL; J. Taylor, C. K. Loo (2007). Stimulus waveform influences the efficacy of repetitive transcranial magnetic stimulation. Journal of Affective Disorders, 97(1-3):271-276. S. M. Goetz, B. Luber, S. H. Lisanby, D. L. K. Murphy, I. C. Kozyrkov, W. M. Grill, A. V. Peterchev (2016). Enhancement of Neuromodulation with Novel Pulse Shapes Generated by Controllable Pulse Parameter Transcranial Magnetic Stimulation. Brain Stimulation, 9(1):39-47].

[0008] While pulse shape has been identified as a key parameter for various applications of magnetic stimulation, currently available devices are fundamentally unable to modify the pulse shape. The main reason for the severe limitation of the pulse shape, usually to sinusoidal waveforms, is the high currents and the high spectral components of excitable pulses. A conventional circuit topology for generating controlled, high-intensity magnetic pulses for transcranial magnetic stimulation is described in Fig. Figure 1 shows a resonant circuit consisting of a high-voltage capacitor C, for example a film capacitor, and a stimulation coil L, connected via a switch Q, for example a transistor. A charging circuit charges the capacitor C to a voltage of several thousand volts. The energy content of the capacitor can be several hundred joules. Closing the switch Q then initiates the current flow through the coil L, generating the stimulation field. However, most of the energy is lost as heat through the resistor R.

[0009] One further development that allows for high flexibility is the one in Fig. 2. Schematic circuit topology shown [AV Peterchev, DLK Murphy, SH Lisanby (2011). Repetitive Transcranial Magnetic Stimulator with Controllable Pulse Parameters. Journal of Neural Engineering, 8(3):036016]. In this half-bridge configuration, the stimulation coil L is alternately switched with the high-voltage capacitors C via switches Q1 and Q2. p or C m connected. The first capacitor C p Energy extracted when switch Q1 is closed, which is not converted into the magnetic pulse in coil L, can at least partially be transferred to the second capacitor C. m The energy is fed back. When switch Q2 is subsequently closed, capacitor C is charged. m then conversely, capacitor C p , so that the waste heat losses compared to the switching configuration of the Fig. 1 are lower. Additionally, the use of two independent capacitors C increases p and C mwith separate charging circuits, the flexibility in generating the pulse shapes.

[0010] Further developments of this technology are described in the scientific literature [AV Peterchev (2011). Circuit Topology Comparison and Design Analysis for Controllable Pulse Parameter Transcranial Magnetic Stimulators. Proc IEEE NES, 5:646-649; AV Peterchev, K. D'Ostilio, JC Rothwell, DLKMurphy (2014). Controllable pulse parameter transcranial magnetic stimulator with enhanced circuit topology and pulse shaping. Journal of Neural Engineering, 11(5):056023.] and patent literature US 7,753,836 B2; US 7,946,973 B2. These technologies use coupled switchable oscillators to provide the high electrical power required for a pulse and increase flexibility to section-wise rectangular pulses with more than two phases, but are not capable of generating arbitrary pulse shapes similar to a digital-to-analog converter.However, such flexibility proves indispensable in order to enable pulse shapes that are recognized as particularly advantageous, for example for increased efficiency and reduced coil heating, increased neuromodulation strength or lower acoustic emissions.

[0011] For this reason, technologies capable of generating arbitrary pulse shapes are the subject of active research and development. In EP 0 958 844 A2, Schweighofer et al. describe a technology that uses a semiconductor circuit and pulse-width modulation to generate arbitrary pulse shapes for neuron stimulation. Insulated-gate bipolar transistors (IGBTs) can be used as semiconductors. While these semiconductor switches, unlike most other established high-voltage switches, can be switched off, they suffer from a very low switching speed. The possible switching speed for pulse-width modulation is therefore approximately in the same frequency range as the fundamental frequency of typical TMS pulses, between 3 kHz and 8 kHz. However, for reasonably accurate pulse generation, the switching rate of the semiconductors should be at least an order of magnitude higher than the highest frequency component of the pulse shape.However, as it subsequently turned out, such high switching rates place IGBTs far outside their specifications, switching losses increase disproportionately, and the IGBTs wear out rapidly or, as a rule, suffer permanent damage after only a few pulses. For this reason, not a single device using this technology is known to have functioned reliably over an extended period.

[0012] Fig. 3 represents an alternative technology that generates the high pulse voltage of several thousand volts and the high switching rate required of at least several hundred kilohertz by summing the output voltage of a large number of bridge modules ( Fig. 4) is represented [SM Goetz et al. (2012). Circuit topology and control principle for a first magnetic stimulator with fully controllable waveform. Proc. EMBS. 4700-4703; US 2011 / 0 144 184 A1]. Each bridge module, or module for short, consists of several semiconductor switches, hereinafter referred to as switches, and at least one electrical energy storage element, hereinafter referred to as energy storage, for example, a capacitor. The switches allow a certain number of electrical storage elements to be connected in series with respect to the output to which the stimulation coil is electrically connected, and allow the remaining electrical storage elements to be electrically disconnected at least at one of their respective terminals, so that they neither absorb nor release charge with respect to the stimulation coil.In this way, the voltage at the stimulation coil can be changed very precisely in steps, and intermediate voltage values ​​can also be generated with sub-step accuracy through switching modulation. Each module can therefore assume multiple states, which are determined by the states of the module's individual switches (e.g., conducting or non-conducting). The states of the switches of all modules define the overall state of the system.

[0013] Since this technology can increase or decrease the output voltage in very small steps and also alternately switch the individual semiconductor switches of the modules, thus distributing the switching load across all semiconductors, it can in principle generate even pulses with very high frequency components with low distortion and avoids the crucial problems of high-voltage circuits, as described, for example, by Schweighofer et al. Furthermore, due to their greater availability, the use of a large number of inexpensive low-voltage semiconductors is significantly cheaper than using a few high-voltage semiconductors.

[0014] The technology described above only allows modules to be connected in series, which is why each module must be designed for the maximum expected current. Furthermore, since the highest current typically flows at low voltages due to the almost exclusively inductive load in the form of the stimulation coil, the current is supplied during this time by only a small number of modules and their module capacitors. The internal resistance and available capacitance are therefore very unfavorable. A further development of the above technology enables a dynamic switching between series and parallel connection of the modules, so that at low voltages a large proportion of the modules can be connected in parallel, while at higher voltages more and more modules switch to a series connection [US 2014 / 0 049 230 A1].

[0015] The switching state of a module, or simply state, refers to the way in which the module's switches are activated or deactivated to electrically connect at least one electrical energy storage device of the module to at least one electrical energy storage device of at least another module in a different way, known as connectivity, or explicitly not connect them (i.e., open circuit or disconnected connection), so that several modules together generate an electrical voltage. Examples of possible connectivity of electrical energy storage devices include parallel and series connections, combinations of electrical energy storage devices, and unconnected energy storage devices or those connected only by a contact. Modules are typically capable of representing at least two of the following states or connectivity forms through their electrical switches: (a) The at least one electrical energy storage device of one module is connected in series with the at least one energy storage device of another module by means of electrical switches; (b) the at least one electrical energy storage device of one module is connected in parallel with the at least one energy storage device of another module by means of electrical switches; (c) the at least one electrical energy storage device of a module is bypassed by means of electrical switches, which means that the at least one electrical energy storage device of a module is electrically connected to an electrical energy storage device of another module only by a maximum of one of its at least two electrical contacts and thus there is no closed circuit with an electrical energy storage device of another module.

[0016] Although these technologies fundamentally enable the generation of arbitrary pulse shapes and, unlike alternative approaches, do not unduly stress power semiconductors or deliver poor pulse quality, they have significant drawbacks. Generating typical magnetic stimulation pulses with voltages of several thousand volts and currents of several thousand amperes requires a large number of bridge modules. Each of these modules employs several individual switches, usually between four and eight, which should be independently controllable to generate free pulse shapes. The large number of independently controllable switches results in a large number of control signals that must be provided. Typical microprocessors, microcontrollers, signal processors, and similar components generally provide about 30 to 80 inputs and outputs. Higher numbers of signals are required in few other technical applications.Furthermore, current package types limit the number of inputs and outputs that can be routed from a semiconductor chip to the outside.

[0017] For a setup of, for example, just forty modules, each with a voltage of 75 V and capable of generating an output voltage of 3000 V, the number of required control lines from the control unit implemented in one or more microprocessors increases to between 160 and 320. These control lines must also be operated with high timing accuracy and high data rate. Typical update rates for the control lines are less than 1 ms, preferably less than 1 µs, to ensure low pulse waveform distortion. Due to the high switching speed of the field-effect transistors typically used, usually less than 100 ns, a timing accuracy of the signals significantly below this switching speed is also required. Consequently, highly accurate signal generation for a large number of parallel channels with a high signal rate in real time is necessary. Technically, this is only achievable with very expensive and rare components.The synchronization of multiple processors to generate the multitude of parallel channels, which is common in other technical fields, is very difficult to achieve due to the required high temporal accuracy, which prohibits jitter of typically over 100 ns.

[0018] A second key problem with this state-of-the-art flexible technology is its high susceptibility to electromagnetic interference. The currents controlled by the semiconductor switches typically exceed several thousand amperes and are supplied and discharged in close proximity to the control signals. For this reason, the aforementioned flexible TMS technology suffers from the intolerable problem that the controlled current feeds back into the control line, and the signals it generates in the control lines are orders of magnitude higher than the intended control signals of the device's control unit. A stimulator that is no longer fully controlled by the control unit according to specifications, but rather self-influencing, is not only impractical for many applications, but also poses a safety risk due to the high energies involved and the interaction with the nervous system, such as the brain.

[0019] While comparable semiconductor circuits from the power engineering sector also control high power levels in the megawatt range and above, the semiconductor switches of the aforementioned flexible TMS technology, unlike similar technologies from the power engineering sector which almost exclusively employ extremely slow high-voltage components such as insulated-gate bipolar transistors (IGBTs) and thyristors, possess very short response times and small gate capacitances. The high-voltage components in the power engineering sector require currents of several amperes even at the control input, the gate, to switch between the conducting and blocking states, resulting in a comparatively low ratio of controlled current to current to be controlled during switching.Since electromagnetic interference must also be in the ampere range to have a noticeable effect, the gate of semiconductors in similar power circuits is significantly less sensitive to self-generated electromagnetic interference. In addition to this insensitivity due to the high control currents required, the corresponding semiconductors are several orders of magnitude slower. Consequently, high-frequency or short electromagnetic interference (often referred to as salt-and-pepper noise or interference spikes) has a negligible effect, as the inertia of the components would be insufficient to follow it.

[0020] Using only one signal channel per half-bridge consisting of two switches connected in series, as is common in power engineering, would reduce the number of required wires. However, this is generally not applicable to the flexible TMS technologies mentioned above, since this single binary signal channel would alternately activate the two switches of the bridge, meaning that one switch would always be conducting. For many pulses in magnetic stimulation, however, when the electrical properties of the stimulation coil are unknown or not precisely known, it is also necessary to operate in a state where neither of the two switches is activated by the control unit, but only diodes (freewheeling diodes; see US 13 / 990,463; US 2011 / 0144184A1; S.M. Goetz et al. (2012). Circuit topology and control principle for a first magnetic stimulator with fully controllable waveform. Proc. EMBS. 4700-4703.The rectifier elements conduct the current in its direction of flow. This state is generally referred to as passive, since no targeted activation of switches by the control unit is necessary, and the control unit does not need to know the current at the stimulation coil to determine the commutation time. Instead, the passive state can be used to discharge the energy of the stimulation coil's inductance by selectively deactivating switches.

[0021] Since the semiconductors of the above-mentioned flexible TMS technologies are, in contrast, usually implemented via very sensitive low-voltage semiconductors, especially field-effect transistors (FETs), which require response times in the nanosecond range and very low control currents, typical solutions from power engineering are only applicable to a very limited extent.

[0022] Optical control lines, instead of electrical ones as commonly used in power engineering, would significantly increase the cost of the stimulation device, making it unaffordable for typical medical practices or scientific laboratories. Furthermore, unlike in power engineering, optically controlled semiconductors are not widely used in low-voltage applications.

[0023] The object of the present invention is therefore to address at least some of the disadvantages of the prior art. At the very least, it aims to propose at least one alternative to known solutions. Disclosure of the invention

[0024] This problem is solved by a method and a device with the features of the respective independent claims. Further embodiments are described in the dependent claims and the description.

[0025] A method for generating short current pulses is proposed using an electronic circuit with at least two electrical switches and at least one electrical energy storage device, wherein at least one electronic control unit emits electrical signals for controlling the at least two electrical switches. These signals are encoded based on a predetermined pattern for the switch states to be set for the at least two electrical switches, are transmitted as encoded electrical signals via an electrical signal transmission line to at least one decoder, and are decoded by the at least one decoder into switch control signals describing each switch state to be set for one of the at least two switches. The respective switch control signals are then transmitted to the respective at least two switches and converted accordingly.wherein current pulses with a total duration of less than five milliseconds are provided at an output of the electrical circuit for excitation of at least one stimulation coil, such that the at least one stimulation coil generates magnetic field pulses with a magnetic flux density of 0.1 to 10 Tesla, which, according to the principle of electromagnetic induction, induce electrical currents in body tissue, which, by stimulation, trigger at least one action potential of nerve and / or muscle cells, wherein the at least one stimulation coil is designed such that a magnetic field generated by it can penetrate the body tissue.

[0026] The at least one electrical energy storage device is designed to store some or all of the energy required for the magnetic field pulses.

[0027] The electrical stimulation currents generated by the magnetic field of the simulation coil are at least one-tenth and at most ten times the stimulation currents required to stimulate the cells.

[0028] In a preferred embodiment, the average data rate or the average redundancy of the coded electrical signals is lower than the corresponding average data rate or the average redundancy of the signals decoded to switch control signals by the at least one decoder.

[0029] Furthermore, a device for generating short current pulses is provided by means of an electronic circuit with at least two electrical switches and with at least one electrical power supply, wherein the device comprises at least: an electronic control unit configured to send electrical signals to control the at least two electrical switches, which are to be transmitted as coded electrical signals via an electrical signal transmission line to at least one decoder; the at least one decoder configured to decode the coded electrical signals into respective switch control signals describing a respective switch state to be set of one of the at least two switches, wherein the respective switch control signals are, when converted at the respective at least two switches, such thatthat current pulses with a total duration of less than five milliseconds are provided at an output of the electronic circuit for the excitation of at least one stimulation coil, so that the at least one stimulation coil, when excited with these current pulses, generates magnetic field pulses with a magnetic flux density of 0.1 to 10 Tesla, which, according to the principle of electromagnetic induction, induce electrical currents in body tissue, which, through stimulation, trigger at least one action potential of nerve and / or muscle cells.

[0030] In a possible embodiment, the device according to the invention comprises at least one coding unit which is configured to encode electrical signals to be sent or transmitted by the electronic control unit on the basis of a predetermined pattern for switch states to be set of the at least two electrical switches and to transmit them as encoded electrical signals via an electrical signal transmission line to at least one decoder.

[0031] In one possible embodiment, the at least one coding unit is integrated into the control unit or is part of the control unit. In another embodiment, the at least one coding unit is integrated into at least one electronic circuit subordinate to the at least one electronic control unit. Alternatively, the coding unit can also be provided as a separate unit, for example in the form of an encoder, or comprise an encoder.

[0032] According to one embodiment of the device according to the invention, the average data rate or the average redundancy of the electrical signals is lower than the corresponding average data rate or the average redundancy of the signals decoded to switch control signals by the at least one decoder.

[0033] The present invention presents a novel solution to the problems of the prior art. Primarily, the invention enables a reduction in the number of control lines, allowing the system to be controlled by at least one control unit using conventional microprocessors from the prior art. Furthermore, it reduces the susceptibility to electromagnetic interference, both from external sources and, in particular, from the pulse current generated by the magnetic stimulator itself, including its switching transitions and peaks.

[0034] Although each semiconductor switch must be individually controlled to generate arbitrary pulse shapes, the totality of the control lines is highly patterned. Furthermore, not all combinations of switching states are necessary for the goal of generating arbitrary pulse shapes. While these properties are specifically utilized in the present invention, the prevailing consensus in the magnetic stimulation technical community has been that the large number of control lines is the necessary price to pay for achieving unprecedented flexibility. Usable patterns in the switching states were not considered obvious, as the large number of switches and the interdependence of their switching states lead to a high degree of complexity that obscures the view of simple structures.For this reason, control signals in existing systems are generated exclusively by computer and not manually, so that even after a targeted numerical entropy analysis, only Shannon's redundancy would be known, but no natural compression possibilities would become apparent. The complexity due to the large number of signals is further increased by switching modulation, which causes very rapid changes between different and usually non-recurring switching states.

[0035] To reduce redundancy, the invention uses encoding at at least one point in the transmission of the control signals, so that instead of using a separate signal for each independently controlled switch, the control signal represents states and partial states. For this purpose, purely parallel encoding, purely serial encoding, or a mixture of parallel and serial encoding can be used to reduce redundancy.

[0036] In a purely parallel encoding, the entirety of all encoded signals at a given time uniquely defines the complete state of all switches. In a purely serial encoding, there is only one signal channel, whose signal, as a serial signal, does not define the state of all switches at a specific time, but rather through the sum of successively transmitted signals. The successively transmitted signals determining the state of all switches must be completely transmitted by the time the switches need to assume the corresponding state. However, the successively transmitted signals determining the state of all switches do not have to follow each other without gaps, but can be interrupted or interleaved, as is used, for example, in the Compact Disc (CD), according to the Red Book standard.In a mixture of parallel and serial encoding, the state of each individual switch is defined in more than one signal channel and at more than one time. Consequently, s successively transmitted signals on k parallel channels define the state of each switch.

[0037] Furthermore, a sequence encoding can be used, which can be purely parallel, purely serial, or mixed parallel-serial. Sequence encoding requires the state of each switch at one or more points in the past to uniquely define its state. In its simplest form, sequence encoding is differential encoding, where a signal is represented as the difference to a previous signal. More complex sequence encodings are also possible, which can be implemented, for example, using shift registers. Reed-Solomon or convolutional codes are examples of more complex sequence encodings.

[0038] According to a first aspect of the invention, the coding unit is implemented by the at least one control unit or at least one subordinate electronic circuit; that is, the at least one control unit or at least one subordinate electronic circuit generates a code that requires fewer signal lines and / or a lower data rate than the prior art method of controlling each switch with one line each. Due to the reduced number of lines, the control signals for the entire system can be generated in a single control unit and electronically output by it, despite the typically small number of inputs and outputs it has.

[0039] One or more electronic circuits are considered to be subordinate to one or more control units if these one or more electronic circuits receive and process electrical control signals from the one or more control units.

[0040] Furthermore, optionally one or more separate encoders can be implemented, which perform the encoding based on control signals from the at least one control unit or at least one subordinate electronic circuit in such a way that its at least one output signal requires a lower data rate than controlling each switch with one line each according to the state of the art.

[0041] At least one decoder determines the required state of at least one electrical switch from the at least one coded signal. A decoder according to the invention can receive only a portion of the at least one signal; for example, in the case of signals transmitted via parallel channels, only some channels; in the case of serially transmitted signals, for example, by evaluating only a few transmission symbols or bits from the entire data stream of the at least one channel; and in the case of, for example, channel multiplexing according to the code-division multiplex access (CDMA) method, only one or a few of the channels can be extracted from the at least one signal. It is further advantageous according to the invention if the at least one decoder is located spatially close to the at least one switch whose state the corresponding decoder determines.This spatial proximity can be further enhanced by a suitable circuit layout to reduce electromagnetic interference.

[0042] In one embodiment, the device according to the invention comprises at least one decoder per module, wherein each decoder of a module is designed to receive only a subset of the totality of coded electrical signals received by the decoders, and / or at least one decoder per inter-module connection, wherein each decoder of an inter-module connection is designed to receive only a subset of the totality of coded electrical signals received by decoders, and / or at least one decoder per inter-module connection unit, wherein each decoder of an inter-module connection unit is designed to receive only a subset of the totality of coded electrical signals received by decoders.

[0043] In one possible configuration, the subsets of the total set of signals received by decoders are not identical.

[0044] In a further refinement, the subsets of the total set of signals received by decoders are pairwise disjoint.

[0045] In a further embodiment, the device according to the invention also comprises at least one channel encoder.

[0046] The at least one channel encoder is designed to receive electronic signals from the at least one encoder.

[0047] The at least one channel encoder can be integrated with the at least one electronic control unit or at least one electronic circuit subordinate to the at least one electronic control unit.

[0048] In a possible embodiment, the electronic circuit has at least two modules, each comprising at least one electrical energy storage device and at least one electrical switch, wherein the at least two modules can assume at least two of the following switching states: The at least one electrical energy storage device of a module is connected in series with the at least one energy storage device of another module using the electrical switches; The at least one electrical energy storage device of a module is connected in parallel with the at least one energy storage device of another module using the electrical switches; The at least one electrical energy storage device of a module is bypassed using electrical switches, meaning that the at least one electrical energy storage device of a module is only electrically connected to an electrical energy storage device of another module with at most half of its at least two electrical contacts, and thus there is no closed circuit with an electrical energy storage device of another module.

[0049] Advantageously, the invention uses a so-called code book that assigns a code or entry to each required state of the system or parts of the system, for example modules, inter-module connections (comprising the switches of a module and its immediate neighbors, i.e., a module that is electrically directly connected to the former, which can establish the direct electrical connections between the electrical energy storage devices of the two modules).The inventor has recognized that, furthermore, certain systems contain states that are not only rarely or never used, but whose use is even detrimental for various reasons, such as an unfavorable energy balance, the risk of a short circuit in one or more energy storage devices due to the simultaneous activation of two or more switches, which would create a direct closed circuit between the terminals of said energy storage device(s), or, in the case of use in a sequence, due to the generation of problematic transition states. According to this advantageous aspect of the invention, the codebook preferably contains only those states that are absolutely necessary to provide the desired flexibility of the pulse shape.So-called forbidden states, for example, those in which two or more switches, when activated simultaneously or overlapping, would short-circuit an energy storage device, are not included in the codebook and are therefore, in principle, not representable. If necessary, forbidden states can be specifically identified and removed from the codebook. The minimum data rate of the signals that the at least one control unit, or at least one subordinate electronic circuit, must transmit to the modules is determined by the number of entries in the codebook. This signal transmission can be purely parallel, purely serial, or mixed parallel / serial, as described above. The codebook can be implemented minimally, meaning that the minimum, usually binary, word length required to uniquely represent all entries in the codebook, and thus all necessary states, is determined.Without limiting the generality, a word can be transmitted electronically in purely parallel, purely serial, or mixed parallel-serial fashion as described above. Alternatively, additional redundancy can be added to facilitate simple error detection or correction. To enable simple implementation, parity codes and convolutional codes are preferred in accordance with the invention.

[0050] For example, if in the case of a binary transmission the number of entries in the codebook, and consequently the number of all required states, does not correspond to a power of two, such redundancy arises automatically.

[0051] Using a codebook with a fixed maximum number of entries has the advantage that the maximum expected data rate of the coded signal(s) is known and, in accordance with the invention, is lower than the maximum data rate of the decoded switch control signals. Switch control signals describe the states of the associated switches. For example, they can include an on / off state bit for each associated switch.

[0052] In accordance with the invention, other source coding methods can also be used to reduce the average data rate and / or the average redundancy of the coded signals [see J. Proakis (2001). Digital Communications. 4th edition, McGraw Hill, Boston.]. Source coding methods that can guarantee a maximum data rate are particularly advantageous in the context of the invention.

[0053] Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings. The invention is schematically illustrated with reference to embodiments in the drawings and is described schematically and in detail with reference to the accompanying drawings. Fig. Figure 1 shows a state-of-the-art magnetic stimulation technology that, for the first time, enables low flexibility in pulse shape. Fig. Figure 2 shows a further development of magnetic stimulation technology from Fig. 1, in which commutation is possible between two high-voltage oscillators, but arbitrary pulses cannot be generated. Fig. Figure 3 shows a prior art magnetic stimulation technology that can, in principle, generate any desired pulse shape. For this purpose, N modules 301-304 are connected to a stimulation coil 305 such that the modules can generate any desired voltage and / or current waveform at the terminals of the stimulation coil 305 by dynamically changing the interconnection of their energy storage devices, including electrically in series and / or electrically in parallel. The switches in the modules are controlled by at least one control unit via at least one electrical control bus 306. Fig. Figure 4 presents two exemplary module circuits 401 and 402 of the technology. Fig. Figure 3. The modules contain at least one energy storage device 403, 404 and at least two semiconductor switches, referred to as switches 405-416, which can be implemented with any typical switching element; field-effect transistors are preferably used. The switches are generally supplemented by freewheeling diodes and also by protective circuitry (so-called snubbers). The switches 405, 406, 409-412 to the left of the energy storage device 403, 404, as well as their freewheeling diodes and protective circuitry, are referred to as side A without limitation of generality. The switches 407, 408, 413-416 to the right of the energy storage device 403, 404, as well as their freewheeling diodes and protective circuitry, are referred to as side B without limitation of generality. Fig. Figure 5 shows two exemplary adjacent modules according to the invention. The switches, which can directly connect the electrical energy storage devices 502, 503 of the two modules electrically, together with their optional protective circuitry 504, form the intermodule connection 501. Instead of the half-bridge arrangement of two switches that each module contributes to the intermodule connection, according to US 2014 / 0 049 230 A1, four switches per module in two half-bridges can form the module's contribution to the intermodule connection in order to enable parallel connection of energy storage devices from different modules. An intermodule connection 501 in turn consists of at least two intermodule connection subunits, wherein the intermodule connection subunits each represent the intersection of the intermodule connection with the respective modules involved.Consequently, the intermodule connection subunit with respect to a module is in each case the share of the corresponding module in the intermodule connection 501. Fig. Figure 6 shows five advantageous states of a particular embodiment in which the states are coded for each intermodule connection. The left column shows the switches of the intermodule connection of two adjacent modules and their at least one energy storage device each. The right column shows the equivalent electrical connections generated by the switches in the corresponding states of the intermodule connection. Specifically, the states shown are serial-positive 601, serial-negative 602, bypass 603, passive 604, parallel 605, and a state 606, defined here as impermissible, in which at least one energy storage device is short-circuited via two or more switches by appropriate activation of switches. This state primarily describes how the electrical energy storage devices of the system are electrically interconnected. This interconnection is dynamically modifiable according to the invention. Fig. Figure 7 shows four typical states of a particular embodiment, in which the states are coded for each intermodule connection subunit. The left column shows the switches of the intermodule connection subunit of a module and its at least one energy storage device. The right column shows the equivalent electrical connections generated by the switches in the corresponding states of the intermodule connection unit. Specifically, the states shown are positive 701, negative 702, passive 703, parallel 704, and a generally prohibited state 705, in which at least one energy storage device is short-circuited via two or more switches by appropriate activation of switches. Fig. Figure 8 shows two exemplary encodings of particular embodiments of the invention, in which the states are encoded for each intermodule connection. Using a suitable partially independent encoding 801, three bits, which are sufficient for the state of an intermodule connection with five different states, can be divided such that two of the three bits, for example the first and the second bit, encode the state of one intermodule connection subunit involved in the intermodule connection (see “for module 1”), while the third bit and one of the two aforementioned bits, for example the second and the third bit, together encode the state of the other intermodule connection subunit involved in the intermodule connection (see “for module 2”).Thus, the partially independent coding 801 is a clever hybrid solution between one coding per intermodule connection and one coding per intermodule connection subunit as defined in the invention, in which each intermodule connection subunit only needs to receive and decode two bits instead of the three bits that would be required for the unambiguous definition of the intermodule connection with five different states in the codebook. For this purpose, bits a and c can be symmetrically configured as in the . Fig. The modules are arranged in row 8 with the reference numeral 801, so that each intermodule connection subunit can use a decoder of the same type. Since the signals generally need to be transmitted to the modules with galvanic isolation (for example, using optocouplers, capacitive, inductive, or other galvanically isolated signal transformers), such a reduction in the amount of data, which leads to a reduction in the number of parallel lines and / or a reduction in the bit rate per line, is extremely advantageous. Alternatively, the third bit of each signal can also be evaluated by the respective decoder to serve as a check bit for detecting transmission errors.

[0054] If, however, the "bypass" state for the intermodule connection is omitted, as in Example 801, the codebook contains four states per intermodule connection, each requiring two binary bits for unambiguous representation. While the code words for the unambiguous description of the intermodule connection's state are shorter than in the semi-independent coding 801, each of the at least two intermodule connection subunits—if decoding is performed by at least two independent decoders, at least one for each intermodule connection subunit—requires both bits for unambiguous decoding and determination of which switches of the respective intermodule connection subunit are to be activated. Thus, the same number of bits per intermodule connection subunit results as in the embodiment shown in Table 801.Such decoding with at least two decoders can be very advantageous, since the decoding can be carried out before the galvanic isolation by galvanic transformers, and thus a smaller amount of data has to be transmitted with galvanic isolation.

[0055] The order of the bits can be arbitrarily swapped without loss of generality. Likewise, the code can be inverted, which means that 0 and 1 are swapped.

[0056] Fig. Figure 9 shows a particular embodiment of the invention comprising at least one control unit 901, at least one galvanically isolating signal transmitter 905, at least one decoder 907 and at least two modules 910, each comprising at least one electronic switch and at least one energy storage device.The modules are designed, in accordance with, for example, US 7 269 037 B2, DE 101 03 031 A1, WO 2012 / 072 197 A2, DE 10 2010 052 934 A1, WO 2012 / 072 168 A2, WO 2013 / 017 186 A2, DE 10 2011 108 920 A1, DE 10 2016 112 250 A1 and DE 10 2015 112 512 A1, such that, by means of at least one switch per module of the aforementioned at least two modules, the electrical connection between at least two energy storage devices can be dynamically switched between at least two of the following states: (a) electrical connection of the energy storage devices in series; (b) electrical connection of the energy storage devices in parallel to each other; (c) Bridging at least one energy storage device in such a way that no charge can flow into or out of the corresponding energy storage device.

[0057] This control unit sends electrical signals 902, for example via an electrical bus, to at least one optional encoder 903, which encodes the signals such that the average data volume and / or the average redundancy of the encoded signals 904 is lower than the corresponding average data volume and / or the average redundancy of the uncoded or decoded switch control signals 909, and / or the average entropy of the encoded signals 904 is higher than that of the uncoded or decoded switch control signals 909. Under special conditions, the maximum data volume of the encoded signals 904 is also lower than the corresponding maximum data volume of the uncoded or decoded switch control signals 909.The switch control signals 909 can, for example, be designed such that for each switch in a group of switches assigned to, for example, decoder 907, at least one separate bit is provided that describes the state (electrically conductive closed vs. electrically non-conductive open) of the corresponding switch. The switch control signals 909 thus describe the switch states of the individual switches.

[0058] As in all embodiments of the invention, the electrical signal connections and buses 902, 904, 906, 908, 909 can transmit data serially, in parallel or mixed serial / parallel without restriction.

[0059] At least one galvanically isolating signal transmitter 905 isolates the electrical voltage level of the signals from the voltage level of the electrical control unit and / or other electronic components.

[0060] Optionally, an electronic circuit subordinate to the at least one control unit 901 and the optional at least one encoder or coder 903 may be included, which receives electrical signals from the at least one control unit 901 or at least one of the latter subordinate electronic circuits and itself sends signals 902 to the at least one encoder or coder 903.

[0061] The order of the optional at least one encoder 903, the at least one galvanically isolated signal transformer 905, and the decoder 907 can be interchanged and / or partially integrated into the modules and / or divided into several parallel units, each processing either all or only a subset of all signals, for example, only for one module at a time. Preferably, the decoding by the at least one decoder 907 always takes place after the optional encoding by the optional at least one encoder 903.

[0062] The electrical power connection 911 between two modules 910 serves for the electrical energy transmission and the electrical interconnection between the energy storage elements of the associated modules and is generally adapted in its design to the module type (for example, M2C four-quadrant modules, see for example US 7 269 037 B2; M2C two-quadrant modules, see for example DE 101 03 031 A1; M2SPC four-quadrant modules, see for example WO 2012 / 072 197 A2, DE 10 2010 052 934 A1, DE 10 2011 108 920 A1, WO 2013 / 017 186 A2; or M2SPC two-quadrant modules, see for example WO 2012 / 072 168 A2, US 2014 / 049 230 A1). adapted and enables, with the help of at least one switch per module, the electrical interconnection of at least one energy storage device of at least two modules 910 to be dynamically changed.For example, the electrical power connection 911 for M2SPC modules is typically implemented with at least two electrical connections to enable parallel connection of modules 910 or electrical energy storage devices. Two modules 910 directly connected electrically via an electrical power connection 911 are generally referred to as neighbors.

[0063] Fig. 10 represents a particular embodiment of the invention in which the coded control signals 1004 are first decoded by at least one decoder 1007 before the decoded signals 1006 are isolated from the voltage level of at least one control unit 1001 by at least one galvanically isolating transformer 1007.

[0064] Fig. Figure 11 shows a particular embodiment of the invention in which at least one decoder 1108 is integrated into at least one module 1109.

[0065] Fig. Figure 12 shows a particular embodiment which further comprises at least one channel encoder 1212 and at least one channel decoder 1215. The at least one channel encoder 1212 selectively adds redundancy to the signal at a specific code rate for error detection and / or error correction [see J. Proakis (2001). Digital Communications. 4th edition, McGraw Hill, Boston.]. The at least one channel decoder 1215 performs error detection and / or error correction and extracts the signal. While coding by at least one optional encoder 1203 reduces the redundancy and prevents impermissible states, such as typically short circuits in an energy storage device, channel decoding reduces the selectively added redundancy.

[0066] Fig. Figure 13 shows an exemplary embodiment that does without the at least one optional encoder.

[0067] Fig. Figure 14 shows a particular embodiment in which at least one galvanically isolating transformer 1405 is present per module, per inter-module connection or per inter-module connection sub-unit, for example also being integrated into the respective module. Detailed description and special designs

[0068] A device for generating stimulation pulses for inductive neuron stimulation according to a first embodiment of the invention comprises at least one stimulation coil and at least three similar modules, the terminals of which are electrically connected to the stimulation coil and which can each assume several switching states.

[0069] In a particular embodiment of the invention, the passive state in the code is represented in such a way that it corresponds to the state that would be determined by the decoder(s) if the at least one control unit or the at least one subordinate electronic circuit performing the encoding is not operational. The at least one control unit or the at least one subordinate electronic circuit performing the encoding is particularly not operational if it is not supplied with the specified voltage, if it is in reset mode, or if it has detected a fault and initiated an emergency shutdown.

[0070] In the case of a control bus with a so-called pull-down resistor, this would be, for example, a permanent low signal on all available channels. In the case of a control bus with a so-called pull-up resistor, this would be, for example, a permanent high signal on all available channels. The inventor recognized that this is particularly advantageous. If a fault shutdown occurs during a pulse, the bypass state of all or several modules represents the fastest way to discharge the magnetic field energy from the coil, since the rectifier diodes typically implemented in the modules dissipate the current at the maximum possible voltage and transfer the energy to the energy storage devices.At the same time, during the initialization of the system, if the modules are ready for use before the at least one control unit or the at least one subordinate electronic circuit performing the coding is only ready after the modules or their decoder(s), no energy is supplied by the system.

[0071] Alternatively, in a particular embodiment, the bypass state, in which a voltage of 0 V is enforced at the terminals of the stimulation coil, is represented in the code in such a way that it corresponds to the state that would be detected by the decoder(s) if the at least one control unit or the at least one subordinate electronic circuit performing the coding were not functioning. In the event of a fault, any remaining current flowing due to magnetic energy stored in the stimulation coil is dissipated at the internal resistance of the coil and the rest of the circuit. The inventor has recognized that this state has the advantage of minimizing the voltage at the terminals of the coil, which, in the event of a fault, could potentially be damaged at the insulation and therefore touched by a user. Furthermore, the coil energy is converted into heat and is thus no longer present in electrical form.For safety reasons, this can be advantageous compared to storage in electrical storage devices in potentially defective modules or modules controlled by a defective control unit.

[0072] In a particular embodiment, at least some signals are not binary, i.e., they use two different electrical symbols, for example. <high>and <low>or <positiv>and <negativ>or <niederohmig>and <hochohmig>, depicted, but higher-level modulation techniques with more than two symbols are used, for example several different voltage levels or other known transmission techniques such as phase-shift keying, quadrature amplitude modulation or the like.

[0073] In a particular embodiment, encoders and decoders are implemented in the at least one control unit or in at least one of those subordinate electronic circuits.

[0074] In a particular embodiment, the respective functions of the at least one encoder and / or at least one decoder are represented in the at least one control unit or in at least one electronic circuit subordinate to that control unit, wherein the at least one control unit or the electronic circuit subordinate to that control unit is a programmable controller, consequently, for example, a microprocessor, a programmable logic controller, a signal processor, a field-programmable gate array (FPGA), a complex programmable logic device (CPLD), a programmable array logic device (PGA), or a comparable circuit.

[0075] In a particularly preferred embodiment, in comparison to the aforementioned particular embodiment, the respective functions of both an encoder and a decoder are represented in the at least one control unit or in at least one of the latter subordinate electronic circuits, wherein the at least one control unit or the at least one of the latter subordinate electronic circuits is a programmable controller.

[0076] In a particular embodiment, the invention does not include an encoder, although coded signals are used for control; consequently, signals that exhibit, for example, lower redundancy or a shorter data length than the state signals of the set of switches, such as the gate signals in the case of transistors. In this particular embodiment, at least one control unit or at least one subordinate electronic circuit directly generates coded signals, which are converted by at least one decoder into control signals for at least one switch of the modules.

[0077] The inventor recognized that control based on coded states is possible. An algebra can be developed with the states of modules, inter-module connections, inter-module connection subunits, and other groupings of multiple switches, which, for example, allows pulse-width modulators and other switching modulators to directly generate coded signals without using a dedicated encoder. The direct generation of coded signals, as described in the invention, without the use of separate encoders, does not limit the invention. An important feature of this aspect of the invention is not the encoding itself, but rather the use of at least one coded signal to control at least one switch of at least one module.

[0078] In a particular embodiment of the invention, at least one switch of at least one module is not controlled by a coded signal from at least one control unit or at least one of the latter's subordinate electronic circuits, but by an electronic signal directly reflecting the state of the switch - for example, a binary signal with a symbol representing the blocking state and a symbol representing the conducting state - from at least one control unit or at least one of the latter's subordinate electronic circuits, while at least one other switch of at least one module is controlled by a signal coded in accordance with the invention from at least one control unit or at least one of the latter's subordinate electronic circuits.

[0079] In a particular embodiment of the invention, the redundancy of the coded control signals 904, 1004, 1104, 1204 is equal to or greater than the redundancy of all the uncoded or decoded switch control signals 1209, 909, for example, in the form of the respective gate signal or a respective binary switch state description of the form on vs. off, of all individual switches of the modules combined. This is particularly in line with the present invention if the average redundancy of the coded control signals is equal to or greater than the said average redundancy of all the uncoded or decoded switch control signals 1209, 909, for example, in the form of the respective gate signal or a respective binary switch state description of the form on vs. off, solely due to channel coding or an error detection / correction code, for example, parity bits or convolutional codes.decoded switch control signals, for example the gate signals of field-effect transistors, IGBTs or the like, and the average redundancy of the coded control signals minus the channel code rate of the coded control signals [see J. Proakis (2001). Digital Communications. 4th edition, McGraw Hill, Boston.] is lower than the average redundancy of the uncoded or decoded switch control signals 1209, 909.

[0080] In a particular embodiment of the invention, the coded signals have a known finite maximum data rate, which is furthermore lower than the maximum data rate of the uncoded or decoded switch control signals.

[0081] In one embodiment of the invention, the at least one decoder comprises at least one programmable logic device, for example a programmable array logic device (PGA), a complex programmable logic device (CPLD), a field programmable gate array (FPGA) or a comparable circuit capable of implementing at least single-channel electronic logic functions.

[0082] In another embodiment, at least one encoder comprises at least one programmable logic module.

[0083] In a particular embodiment, the aforementioned at least one programmable logic block is designed such that the state of at least one electronic input signal of the at least one programmable logic block at a certain time generally fully defines all electronic output signals of the at least one programmable logic block.

[0084] In a particular embodiment, the aforementioned at least one programmable logic block is designed such that the state of at least one electronic output signal of the at least one programmable logic block is not fully defined by its electronic input signals at a specific time, but is fully defined by its electronic input signals at at least two specific times.

[0085] In a particular embodiment, the aforementioned at least one programmable logic block is designed such that the state of at least one electronic output signal of the at least one programmable logic block is influenced, in addition to the state of at least one input signal, at at least one time by at least one state of at least one electronic output signal from the past.

[0086] In a particular embodiment, at least one of the aforementioned, possibly several, programmable logic blocks is programmable exactly once, i.e., it can be modified so that it permanently assumes the logic function necessary or advantageous for its operation, which describes the relationship between the at least one output signal and the at least one input signal.

[0087] In a particular embodiment, at least one of the aforementioned, or possibly several, programmable logic modules can be programmed multiple times. This embodiment is particularly advantageous because the encoding and communication with at least one control unit of devices in the field can be modified, for example, to equip them with a more advantageous encoding or decoding, to increase their flexibility, to change their control behavior, or to modify the codebook. Furthermore, the components can thus be very easily adapted and used for a second purpose (so-called second life) in a different product or product type, for example, in an energy technology, medical technology, or automotive application, simply by reprogramming them.

[0088] In a particularly preferred embodiment, at least two of the modules necessarily have, in addition to a series state in which the electrical energy storage devices of two or more modules can be temporarily connected electrically in series, a parallel state in which the electrical energy storage devices of two or more modules can be temporarily connected electrically in parallel with each other. Module-based coding

[0089] In a particular embodiment of the invention, the signals of at least three modules are encoded independently of one another. This means that decoding the encoded control signals, and consequently determining which switches of the module are to be activated, requires no information about the state of other modules. Therefore, the signals can be physically separated from other modules, for example, by transmitting them via independent parallel data lines assigned to the respective modules.

[0090] Preferably, each module has at least one dedicated data line assigned to it, originating from the at least one control unit or from the at least one subordinate electrical circuit performing the encoding, via which the coded signals controlling the module are transmitted to said module.

[0091] In a particularly preferred embodiment, the codebook of the aforementioned embodiment contains a maximum of four states {bypass, serial positive, serial negative, passive}; in the bypass state at least one energy storage device of the module is not electrically connected to any of the neighboring modules; wherein in the serial-positive state at least one energy storage device of the module is electrically connected with the two neighboring modules with a predetermined polarity such that one contact of the energy storage device is electrically connected to one neighboring module and the other contact of the energy storage device is electrically connected to the other neighboring module; wherein in the serial-negative state the energy storage of the module is electrically connected to the two neighboring modules with polarity reversed compared to the serial-positive state, such that one contact of the energy storage is electrically connected to one neighboring module and the other contact of the energy storage is electrically connected to the other neighboring module; In the passive state, the module's switches are either deactivated and only freewheeling diodes conduct current, or alternatively, the switches are operated as rectifiers (so-called synchronous rectifier).

[0092] In a further particularly preferred embodiment, the codebook of the aforementioned embodiment additionally contains the following states: {parallel side A and serial positive side B, parallel side A and serial negative side B, parallel side A and parallel side B, serial positive side A and parallel side B, serial negative side A and parallel side B}; where in the state<parallel Seite X und seriell positiv Seite Y> The switches on side X of the module are activated in such a way that at least one energy storage device of the module is connected in parallel with the energy storage device of the module immediately adjacent to side X. The duls is electrically connected and a predefined contact of the aforementioned energy storage device, for example the positive one, is electrically connected to the module immediately adjacent to side Y; where in the state<parallel Seite X und seriell negativ Seite Y> the switches on side X of the module are activated in such a way that at least one energy storage device of the module is electrically connected in parallel with the energy storage device of the module immediately adjacent to side X, and the other contact of said energy storage device, for example the negative one, is electrically connected with the module immediately adjacent to side Y; where in the state<parallel Seite X und parallel Seite Y> The switches of the module are activated such that at least one energy storage device of the module is electrically connected in parallel with at least one energy storage device of each of the two adjacent modules, and where X and Y can each be either A or B.

[0093] Another particularly preferred embodiment of the invention differs from the one mentioned immediately preceding in that the codebook necessarily does not contain a bypass state. As a result, the number of states corresponds to a power of two and can be transmitted with very low data usage on binary channels or data buses. The inventor recognized that the bypass state is not necessary to achieve flexibility with regard to the pulse shape and that its function can be represented by other module states.

[0094] Another particularly preferred embodiment uses at least two bypass states, wherein a second bypass state, which is here referred to as the bypass inverse state without loss of generality, differs from a first bypass state by inverting at least two electronic switches, whereby in this second bypass state at least one energy storage device of the module is also not electrically connected to one of the neighboring modules, although the current flows through other electronic switches. Intermodule connection coding

[0095] The coding described above for each module is particularly well-suited when only serial, bypass, and passive states are used for control, but no parallel states. This may be because they are not required for the application or because they are not implemented by the module type used (see, for example, module type 401 in...). Fig. 4) The inventor recognized that different encodings are highly advantageous when using parallel states. When encoding the states for each module, it is easy to represent module state combinations in which one module can short-circuit the energy storage of another. Such combinations indicate, on the one hand, potential for data compression, and on the other hand, that such combinations must not be included in the code book. An initially unconventional possibility, because it contradicts the module circuit structures, is the independent encoding of inter-module connections, i.e., the switches of two immediately adjacent modules that enable the direct electrical connection of the energy storage of the two modules through appropriate activation.While up to nine important states should be considered in the codebook at the module level for flexible operation, analyses show that the number of states at the level of inter-module connections can be reduced to five or fewer without limiting the flexibility of the overall system.

[0096] In a particular embodiment of the invention, the signals of each intermodule connection are encoded independently of one another. This means that decoding the encoded control signals, and consequently determining which switches of the module are to be activated, requires no information about the state of other intermodule connections. An intermodule connection comprises only those switches of the two modules connected by the intermodule connection that are necessary to represent all electrical connection states of the energy storage devices of the two modules. Due to their independence from other intermodule connections, the control signals of the individual intermodule connections can be physically separated, for example, by independent parallel data lines assigned to the respective intermodule connections.

[0097] Preferably, each intermodule connection receives at least one dedicated data line from the at least one control unit or from the at least one subordinate electrical circuit performing the encoding, via which the coded signals controlling the module are transmitted to said module. Particularly preferably, each intermodule connection receives at least two dedicated data lines, at least one of which supplies signals only to the part of the intermodule connection belonging to one of the two modules (so-called intermodule connection subunit).

[0098] In a particularly preferred embodiment, the codebook of the aforementioned embodiment for an intermodule connection contains a maximum of four states {bypass, serial positive, serial negative, passive}; wherein in the bypass state only one of the two electrical terminals of at least one energy storage device of at least one of the modules connected by the intermodule connection is electrically connected to the equivalent electrical terminal of at least one energy storage device of at least one other module connected by the intermodule connection, for example only the negative terminals of the energy storage devices are electrically connected, while the positive terminals remain electrically unconnected; wherein in the serial positive state a previously defined electrical connection (for example the positive one) of at least one energy storage device of one of the modules connected by the intermodule connection is electrically connected to the non-equivalent (in the above example consequently now the negative) electrical connection of at least one other of the modules connected by the intermodule connection; wherein the serial negative state is the inverse of the serial positive state and consequently a predetermined electrical connection (for example the negative) of at least one energy storage device of one of the modules connected by the intermodule connection is electrically connected to the non-equivalent (in the above example consequently now the positive) electrical connection of at least one other of the modules connected by the intermodule connection and the electrically connected electrical connections of the connected energy storage devices do not correspond to those of the serial positive state; In the passive state, the switches of the intermodule connection are either deactivated and only freewheeling diodes conduct current, or alternatively, the switches are operated as rectifiers (so-called synchronous rectifier).

[0099] In a further particularly preferred embodiment, the codebook of the aforementioned embodiment additionally includes at least one parallel state for the intermodule connection; wherein the parallel state activates the switches of the intermodule connection such that at least one energy storage device of one of the modules connected by the intermodule connection is electrically connected in parallel with at least one energy storage device of another of the modules connected by the intermodule connection.

[0100] Another particularly preferred embodiment differs from the aforementioned embodiment in that the codebook does not contain a bypass state. The inventor recognized that this bypass state can be replaced by other states, in particular the parallel state, without significantly impairing the flexibility of the overall system. This allows the number of states to be reduced very easily to a power of two, so that the states can be encoded into binary signals with minimal redundancy. Intermodule connection subunit coding

[0101] In a particular embodiment, the state of each intermodule connection subunit is coded separately. The codebook of this particular embodiment contains at least three states (positive, see Fig. 7 701, negative 702, passive 703); wherein in the positive state one of the two electrical connections of at least one energy storage device of the module belonging to the intermodule connection subunit is electrically connected to at least one module connection of the intermodule connection subunit; wherein in the negative state one of the two electrical connections of at least one energy storage device of the module belonging to the intermodule connection subunit is electrically connected to at least one module connection of the intermodule connection subunit; In the passive state, the switches of the intermodule connection are either deactivated and only freewheeling diodes conduct current, or alternatively, the switches are operated as rectifiers (so-called synchronous rectifier).

[0102] In a particularly preferred embodiment, the code book additionally includes a parallel state (704) compared to the aforementioned particular embodiment; wherein in the parallel state each of the two electrical connections of at least one energy storage device of the associated module is electrically connected to another module connection of the intermodulation connection unit by appropriate activation of the switches of the intermodulation connection subunit.

[0103] Another particularly preferred embodiment differs from the aforementioned embodiment in that the codebook does not contain a bypass state. As already described, the bypass state can be replaced by other states, in particular the parallel state, without any significant loss of flexibility in the overall system. This allows the number of states to be significantly reduced, thus decreasing the bit width of the signals. Interlinking several separate coding units to form a semi-independent coding system

[0104] In one embodiment of the invention, the states of at least two different, disjoint subunits of the system, for example modules, module groups, intermodule connections and intermodule connection subunits, can be encoded in such a way that the encoding of each of these subunits of the system becomes partially independent, that is, that at least a part of the common signal is required for each of the at least two different disjoint subunits to uniquely determine the respective state. Fig. As shown in Figure 8, codes can be used that jointly encode the states of at least two different, disjoint subunits, such as an intermodule connection, in such a way that not the entire codeword, but only a part of it, is needed to uniquely determine the respective state of each of these at least two different, disjoint subunits. However, usually a part of the codeword is required for the unique decoding of the state of several of these at least two different, disjoint subunits.

[0105] This embodiment has the advantage over separate coding for each intermodule connection subunit that only a small number of signal channels need to be galvanically isolated. Signals can be galvanically isolated using galvanically isolating signal transmitters, also known as isolating signal transmitters, such as optocouplers, capacitive signal transmitters, or similar electrical components.

[0106] Furthermore, each subunit can use the signal of at least one subunit with which its signals are partially independent for error detection and / or error correction.

[0107] In a particular embodiment of the invention, the encoding is implemented in such a way that at least two decoders receive at least one signal that is the same for the at least two decoders, as at least one so-called common bit, as an input signal.

[0108] In a particularly preferred embodiment, this at least one common bit is transmitted on a separate electronic signal line from the at least one control unit or at least one electronic circuit subordinate to this control unit. Advantageously, the signal for this separate electronic signal line can be generated with only one output pin of the at least one control unit or at least one electronic circuit subordinate to this control unit, and furthermore, can be transmitted in only a single signal line and only branched or looped through in the form of a bus close to the at least two decoders. This allows for savings in technical resources.

[0109] In a particularly preferred embodiment, this at least one common bit determines the sign of the voltage, and consequently the polarity of each otherwise independently coded unit. This particularly preferred embodiment has the advantage that, in many applications, the modules, inter-module connections, and the like can use the same polarity at any given time without any significant loss of flexibility in the generated current and voltage waveforms.

[0110] In a particular embodiment, the state of each half-bridge, which consists of at least two electrical switches connected in series, is coded separately. The codebook of this particular embodiment contains at least three states (positive, negative, passive); wherein in the positive state one of the two electrical connections of at least one energy storage device of the module belonging to the intermodule connection subunit is electrically connected to at least one module connection of the intermodule connection subunit; wherein in the negative state one of the two electrical connections of at least one energy storage device of the module belonging to the intermodule connection subunit is electrically connected to at least one module connection of the intermodule connection subunit; In the passive state, the switches of the intermodule connection are either deactivated and only freewheeling diodes conduct current, or alternatively, the switches are operated as rectifiers (so-called synchronous rectifier).

[0111] The description of the preferred embodiments and the figures serve only as an exemplary explanation and illustration of the invention and the advantages achieved with it, but are not intended to limit the invention.< / hochohmig> < / niederohmig> < / negativ> < / positiv> < / low> < / high>

Claims

[1] Device for generating short current pulses by means of an electronic circuit with at least two electrical switches and with at least one electrical energy storage device, the device comprising at least: an electronic control unit (901, 1001, 1101, 1201, 1301, 1401) configured to send electrical signals to control the at least two electrical switches, which are to be transmitted as coded electrical signals via an electrical signal transmission line (904, 906, 1004, 1006, 1104, 1106, 1107, 1204, 1213, 1214, 1206, 1302, 1306, 1404) to at least one decoder (907, 1005, 1108, 1207, 1307, 1407), which the at least one decoder (907, 1005, 1108, 1207, 1307, 1407), which is configured to decode the coded electrical signals into respective switch control signals describing a switch state to be set for one of the at least two switches,wherein the respective switch control signals, when implemented at the respective at least two switches, are such that current pulses with a total duration of less than five milliseconds are provided at an output of the electronic circuit for the excitation of at least one stimulation coil (101, 201, 305), so that the at least one stimulation coil, when excited with these current pulses, generates magnetic field pulses with a magnetic flux density of 0.1 to 10 Tesla, which, according to the principle of electromagnetic induction, induce electrical currents in body tissue, which, through stimulation, trigger at least one action potential of nerve and / or muscle cells. [2] Device according to claim 1, wherein the average data rate or the average redundancy of the coded electrical signals is lower than the corresponding average data rate or the average redundancy of the signals decoded to switch control signals by the at least one decoder. [3] Device according to claim 1 or 2, comprising at least one coding unit configured to encode electrical signals to be sent or transmitted by the electronic control unit on the basis of a predetermined pattern for switch states to be set of the at least two electrical switches. [4] Device according to claim 3, wherein the at least one coding unit is integrated into the control unit (901, 1001, 1101, 1201, 1301, 1401) or into at least one electronic circuit subordinate to the at least one electronic control unit. [5] Device according to claim 3, wherein the at least one coding unit is a unit separate from the control unit and comprises at least one encoder (903, 1003, 1103, 1203, 1403). [6] Device according to any one of claims 1 to 5, wherein the electronic circuit comprises at least two modules, each comprising at least one electrical energy storage device and at least two electrical switches, wherein the at least two modules can assume at least two of the following switching states: - the at least one electrical energy storage device of a module is connected in series with the at least one energy storage device of another module using the electrical switches; - the at least one electrical energy storage device of a module is connected in parallel with the at least one energy storage device of another module using the electrical switches; - The at least one electrical energy storage device of a module is bypassed using electrical switches, meaning that the at least one electrical energy storage device of a module is only electrically connected to an electrical energy storage device of another module with at most half of its at least two electrical contacts, and thus there is no closed circuit with an electrical energy storage device of another module. [7] Device according to claim 6, wherein the device further comprises at least one galvanically isolating signal transmission unit. [8] Device according to claim 7, wherein the galvanically isolated signal transmission unit is configured to transmit at least some of the coded electrical signals. [9] Device according to any one of claims 6 to 8, wherein the device comprises at least one decoder per module, wherein each decoder of a module is designed to receive only a subset of the totality of coded electrical signals received by the decoders, and / or wherein the device comprises at least one decoder per inter-module connection, wherein each decoder of an inter-module connection is designed to receive only a subset of the totality of coded electrical signals received by decoders, and / or wherein the device comprises at least one decoder per inter-module connection unit, wherein each decoder of an inter-module connection unit is designed to receive only a subset of the totality of coded electrical signals received by decoders. [10] Device according to claim 9, wherein the respective subsets of coded electrical signals received by different decoders are not identical, in particular pairwise disjoint. [11] Device according to any one of claims 1 to 10, wherein the device further comprises at least one channel encoder (1212). [12] Device according to claim 11, wherein the at least one channel encoder is integrated into the at least one electronic control unit or into at least one electronic circuit subordinate to the at least one electronic control unit.

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