Versatile Neural Stimulation Control via Digital Feedback

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Solution Overview

Problem

Current neural stimulation devices lack flexibility and efficiency, as they typically implement only one stimulation mode (constant voltage or constant current) and suffer from power inefficiency, stability issues due to large HV transistors, and limited applicability to various electrodes, restricting their use in implantable biomedical applications.

Innovation Solution

A control device for neural stimulation that reconfigures a conventional current-controlled stimulator into a versatile mode capable of both constant voltage and constant current stimulation using a digitally controlled feedback loop, eliminating static biasing currents and allowing class B operation, thereby reducing power and area consumption, and incorporating an ADC unit to digitize electrode voltage relative to a preset reference for real-time control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional current-controlled stimulator architecture is used, then the device structure is simple, but the device lacks flexibility and cannot switch between voltage and current modes

Engineering Contradiction:
Improvestimulation mode flexibilityVSAvoidcontrol circuit complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements a universal control device that can operate in both constant voltage and constant current stimulation modes by integrating a voltage measurement unit, ADC unit, and digital control unit that dynamically switches between control modes based on feedback signals, allowing a single device to perform multiple stimulation functions

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent employs feedback mechanisms where the voltage measurement unit continuously monitors electrode voltage and feeds it to the ADC unit, which converts it to digital signals for the digital control unit to process, enabling real-time adjustment of stimulation parameters to maintain desired voltage or current levels dynamically

Inventive Principle:
Principle #23Feedback

2Reliability

If static biasing currents are used in HV domain, then the circuit operates reliably, but power consumption increases

Engineering Contradiction:
Improvecircuit stabilityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent eliminates static biasing currents by implementing periodic sampling action where the voltage measurement unit and ADC unit periodically measure and update electrode voltage, allowing the system to maintain reliability through intermittent monitoring rather than continuous current flow, thereby reducing power consumption

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system uses the existing electrode voltage signals to self-regulate by converting them to digital signals and using them for control decisions, eliminating the need for external biasing currents that would otherwise be required to maintain circuit operation

Inventive Principle:
Principle #25Self-service

3Stability of the object's composition

If large HV transistors are used for stability, then the circuit is stable, but the area consumption increases

Engineering Contradiction:
Improvecircuit stabilityVSAvoidchip area
Core Design Contradiction:
Stability of the object's compositionVSArea of moving object

Solution Approach 1:

The patent replaces large analog HV transistors with a digital control system consisting of ADC unit and digital control unit that process voltage signals digitally, substituting mechanical/analog components with digital logic that achieves similar stability functions with smaller area footprint

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Adaptability or versatility

If only one stimulation mode is implemented, then the device is simple, but the applicability to various electrodes is limited

Engineering Contradiction:
Improveelectrode compatibilityVSAvoidcontrol mechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic mode switching capability where the control device can transition between constant voltage and constant current modes based on real-time feedback from the voltage measurement unit and control decisions from the digital control unit, adapting to different electrode requirements dynamically rather than being fixed to a single mode

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3539609B1Versatile control for a neural stimulation device
Publication Date: 2021.04.28 UNIV ULM
  • EP3539609B1 patent drawingFigure 1~2
  • EP3539609B1 patent drawingFigure 3~4

AI summary

The invention relates to a control device (1) for a neural stimulation device (2) comprising an electrode voltage connector (3) configured to be connected to the neural stimulation device (2) for obtaining an electrode voltage (VEL)of the neural stimulation device (2); a current control signal connector (4, 4') configured to be connected to the neural stimulation device (2) for providing a current control signal (b[5:0], b[5], b[4:0]) to the neural stimulation device (2), where an electrode current of the neural stimulation device (2) is controlled by the current control signal (b[5:0], b[5], b[4:0]); a analog-to-digital converter unit (5) configured to digitize an input voltage, which is the electrode voltage (VEL) obtained via the electrode voltage connector (3) or a converted voltage corresponding to the electrode voltage (VEL) obtained via the electrode voltage connector (3) subtracted from a preset reference voltage (Vref), and to provide a digital output signal as a result of the digitization; and a digital control unit (6) configured to generate the current control signal (b[5:0], b[5], b[4:0]) in dependence upon the digital output signal provided by the analog-to-digital converter unit (5) and provide the current control signal (b[5:0], b[5], b[4:0]) to the current control signal connector (4, 4'), in order to provide a power-efficient control for a versatile and reliable use of a neural simulation device (2).