Electrode Charge Removal via Global Shorting in Implantable Stimulators
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Solution Overview
Problem
Implantable stimulators face charge imbalances due to inherent imperfections in current sources, leading to excess charge accumulation on electrodes, which can inhibit stimulation and cause device malfunction, with existing solutions like DC-blocking capacitors and bleed resistors being inefficient or undesirable.
Innovation Solution
Applying a plurality of stimulation events to electrodes and globally shorting them during interspersed periods to remove accumulated charge, optimizing charge balance and preventing build-up.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If DC-blocking capacitors are used to block long term DC current, then charge build-up on electrodes is eliminated, but PCB space is consumed and DC bias voltage may form inhibiting stimulation
Solution Approach 1:
The patent extracts the charge accumulation problem from the electrode system by introducing a dedicated discharge path through the test structure. The test structure acts as a separate component that absorbs excess charge, removing it from the electrode system without requiring space-consuming capacitors on the PCB. This extraction approach resolves the contradiction by eliminating charge build-up while preserving PCB space for other functional elements.
2Reliability
If bleed resistors are used to remove built-up charge, then charge accumulation is eliminated, but device size increases and current source accuracy is reduced
Solution Approach 1:
The patent introduces a test structure as an intermediary component between the electrode and ground. This test structure serves as a dedicated charge discharge path that mediates the removal of excess charge without requiring large bleed resistors. The test structure provides a controlled discharge mechanism that eliminates charge accumulation while maintaining compact device size and preserving current source accuracy, thereby resolving the contradiction between charge balance and device complexity.
3Productivity
If charge imbalances occur due to current source imperfections, then stimulation can be maintained, but excess charge accumulates on electrodes causing malfunction
Solution Approach 1:
The patent implements preliminary action by continuously monitoring electrode charge levels and proactively discharging excess charge before it accumulates to problematic levels. The test structure is configured to detect and remove charge imbalances during normal operation, preventing the development of conditions that would lead to device malfunction. This proactive approach maintains stimulation continuity while preventing charge-related failures.
Solution Approach 2:
The patent employs feedback mechanisms where the test structure monitors charge accumulation on electrodes and provides information back to the control system. Based on this feedback, the system adjusts stimulation parameters or activates discharge paths to remove excess charge. This closed-loop feedback system maintains charge balance during operation, preventing device malfunction while ensuring continuous effective stimulation.
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
This method effectively maintains charge balance, prevents electrode charge accumulation, and enhances the overall stimulation experience by ensuring efficient and continuous operation of implantable stimulators.
Implementation Method 1
The electrical stimulation pulses may then be applied directly to auditory nerves within the cochlea via one or more of the electrodes
Implementation Method 2
charge imbalances often occur wherein an unequal amount of positive and negative charge is applied via one or more electrodes. Over time, charge imbalances may result in excess charge accumulating on the electrodes
Data Source
AI summary
Methods of removing accumulated charge from one or more electrodes include applying a plurality of stimulation events to one or more stimulation sites within a patient via the one or more electrodes and globally shorting each of the electrodes during a plurality of global shorting periods interspersed among the plurality of stimulation events. Systems for removing accumulated charge from one or more electrodes include a stimulator electrically coupled to the one or more electrodes and configured to apply a plurality of stimulation events to one or more stimulation sites within a patient via the one or more electrodes. The stimulator is further configured to globally short each of the electrodes during a plurality of global shorting periods interspersed among the plurality of stimulation events.