Implantable Neurostimulator with RF Power Saturation Control
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Solution Overview
Problem
Current neurostimulators are bulky and uncomfortable for patients due to their size and weight, requiring surgical implantation and periodic battery replacement or recharging, and lack precise control over energy delivery to bioelectrically excitable tissues.
Innovation Solution
An implantable neurostimulation system powered externally through RF or ultrasonic energy, using a pulse-width modulated excitation signal to limit energy output and ensure consistent stimulation, reducing device size and eliminating the need for batteries, with circuitry that saturates energy delivery to maintain a constant output voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a battery-powered neurostimulator is implanted, then continuous stimulation can be provided, but the device becomes bulky and requires periodic battery replacement or recharging
Solution Approach 1:
The patent extracts the energy source (battery) from the implantable neurostimulator, leaving only the essential stimulation circuitry. The external RF exciter serves as the separate energy source, transmitting power wirelessly through the skin to the implantable device, thereby eliminating the bulky battery component while maintaining continuous stimulation capability.
Solution Approach 2:
The patent replaces the mechanical/battery-based power system with an RF wireless energy transmission system. Instead of using a physical battery that requires replacement, the system uses electromagnetic fields to transmit energy inductively through the skin to power the implantable neurostimulator continuously.
2Power
If traditional neurostimulators are used, then stimulation can be provided, but precise control over energy delivery to tissues is lacking
Solution Approach 1:
The patent implements feedback control where the implantable neurostimulator monitors the actual stimulation output and adjusts its operation accordingly. The system includes circuitry that measures the energy delivered to tissue and provides feedback signals to modify the excitation waveform, ensuring precise and consistent energy delivery despite variations in tissue impedance or coupling conditions.
Solution Approach 2:
The patent employs dynamic adjustment of stimulation parameters in real-time. The neurostimulator continuously adapts its output based on measured tissue conditions, varying pulse width, amplitude, and frequency dynamically to maintain optimal stimulation while preventing over-stimulation or tissue damage.
3Use of energy by moving object
If larger neurostimulators are implanted, then more energy can be stored and delivered, but patient discomfort and surgical trauma increase
Solution Approach 1:
The patent removes the energy storage component (battery) from the implantable device, transferring the energy storage function to an external RF exciter. This extraction allows the implant to be minimized to only the essential stimulation circuitry, dramatically reducing its size and the associated surgical trauma while maintaining adequate energy delivery capability through continuous wireless power transfer.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system achieves precise control over neurostimulation charge delivery, reducing patient discomfort and surgical trauma by minimizing device size and weight, while ensuring safe and consistent energy transfer to tissues, independent of extraneous variables.
Implementation Method 1
An implantable neurostimulation system powered externally through RF or ultrasonic energy
Implementation Method 2
powered externally through RF or ultrasonic energy
Implementation Method 3
circuitry that saturates energy delivery to maintain a constant output voltage
Data Source
AI summary
A system for providing neurostimulation includes an external device (“external exciter”) and an implanted device. The external exciter includes an energy source which inductively powers the implanted device. Examples of such external exciters include devices having at least one of: ultrasonic transducers, Radio Frequency (RF) transmitters, and solar cells. The implanted device includes circuitry that limits its maximum energy output to a predetermined saturation threshold such that excess stimulation from the external exciter does not raise the output of the implanted device beyond the saturation threshold. The output signal of the external exciter is then pulse-width modulated in order to produce a desired amount of output stimulation from the implanted device to stimulate the bioelectrically excitable tissue at a desired level.