Implantable Pulse Generator Output Architecture for Virtual Electrodes
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Solution Overview
Problem
Existing neurostimulation systems are unable to efficiently create virtual electrodes using both time-multiplexed and simultaneous current delivery with low-overhead current regulators, and lack the ability to manage charge build-up across electrodes and DC blocking caps, affecting patient safety and stimulation efficiency.
Innovation Solution
An output architecture for implantable pulse generators that includes a global source and sink current regulator, branch selectors, and discharge switches, enabling efficient virtual electrode creation and management of electrode potentials through fractionalized current sourcing and sinking, as well as passive discharge of non-active electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If virtual electrodes are created using interleaved stimulation pulses with low-overhead current regulators, then device complexity is reduced, but the ability to create virtual electrodes using both time-multiplexed and simultaneous current delivery is lost
Solution Approach 1:
The current delivery system is segmented into multiple independent current regulators (first current regulator for anodic current, second current regulator for cathodic current). Each regulator operates independently to deliver current through specific electrodes, enabling flexible virtual electrode creation through both time-multiplexed and simultaneous delivery modes while maintaining low overhead complexity
Solution Approach 2:
The system dynamically switches between time-multiplexed current delivery (using one regulator at a time) and simultaneous current delivery (using both regulators concurrently) based on the virtual electrode creation requirements. This dynamic adaptability allows the system to optimize between complexity and versatility depending on the operational mode
2Ease of operation
If a passive discharge current path is included for active electrodes, then electrode discharge capability is improved, but the ability to monitor or discharge non-active electrodes is lost
Solution Approach 1:
The discharge current path is designed with switching circuitry that can route discharge current to any electrode regardless of its active or non-active status. The same discharge path serves multiple functions: discharging active electrodes during normal operation and monitoring/discharging non-active electrodes when needed, eliminating the need for separate discharge paths for different electrode types
3Device complexity
If charge build-up is not managed across DC blocking caps and electrode/tissue interfaces, then device complexity is reduced, but patient safety and electrode reliability are compromised
Solution Approach 1:
Discharge paths and monitoring circuitry are pre-configured in the system architecture to proactively manage charge accumulation before it reaches dangerous levels. The system continuously monitors potentials across DC blocking caps and electrode/tissue interfaces and activates discharge mechanisms when thresholds are approached, preventing safety issues before they occur rather than reacting to them
Data Source
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AI summary
The present disclosure provides systems and methods for an output architecture for an implantable pulse generator of a neurostimulation system. The output architecture includes a power supply, a plurality of outputs, a global source current regulator coupled to the power supply and operable to source current from the power supply to the plurality of outputs through a plurality of source current branches, a global sink current regulator operable to sink current from the plurality of outputs to ground through a plurality of sink current branches, a current source branch selector operable to select, for each of the plurality of outputs, an amount of current sourced from the plurality of source current branches, and a current sink branch selector operable to select, for each of the plurality of outputs, an amount of current sunk to the plurality of sink current branches.