Implantable Pulse Generator Current Architecture for Multi-Electrode Control
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Solution Overview
Problem
Current implantable pulse generators (IPGs) for spinal cord stimulation systems face challenges in efficiently managing stimulation currents and electrode interactions, leading to suboptimal therapy delivery and potential tissue damage due to limitations in current control and electrode selection.
Innovation Solution
The improved IPG architecture incorporates a microcontroller-integrated ASIC with pulse definition circuits and DACs that allow for precise control of stimulation currents across multiple electrodes, enabling concurrent pulse generation and flexible current distribution between anodes and cathodes, along with passive charge recovery mechanisms to ensure safe and efficient tissue stimulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional IPG architecture with separate microcontroller and ASIC is used, then device functionality is achieved, but current control precision and electrode management efficiency are insufficient
Solution Approach 1:
The patent integrates the microcontroller unit (MCU) directly into the ASIC chip, creating a unified monolithic structure. This merging eliminates the need for separate microcontroller and ASIC components, reducing overall device complexity while enabling more precise current control through dedicated pulse definition circuits and digital-to-analog converters (DACs) that are co-located with the control logic on the same chip.
Solution Approach 2:
The integrated ASIC contains multiple functional blocks including pulse definition circuits, DACs, and electrode management circuits that can handle multiple stimulation electrodes simultaneously. This multi-functional design allows a single chip to perform current generation, modulation, and distribution to multiple electrodes, improving current control precision without requiring additional separate components.
2Reliability
If simple current generation is used, then device simplicity is maintained, but therapy delivery optimization and tissue safety are compromised
Solution Approach 1:
The patent incorporates pulse definition circuits that pre-configure stimulation pulse parameters (amplitude, width, frequency) before current delivery to electrodes. This preliminary configuration ensures that only safe and therapeutically appropriate current parameters are delivered to tissue, preventing harmful current patterns while maintaining controlled and optimized therapy delivery.
Solution Approach 2:
The integrated ASIC includes circuits that monitor and regulate current delivery to electrodes in real-time. This feedback mechanism ensures that current parameters remain within safe limits for tissue stimulation while optimizing therapeutic effect, automatically adjusting current delivery based on measured parameters to prevent tissue damage.
3Adaptability or versatility
If limited electrode control is used, then device simplicity is maintained, but therapy customization and efficacy are reduced
Solution Approach 1:
The patent divides the electrode array into multiple independently controllable groups or channels, each managed by dedicated circuitry within the ASIC. This segmentation allows selective activation and independent control of different electrode subsets, enabling customized stimulation patterns and improved therapy adaptability while maintaining a unified integrated chip architecture that manages the complexity internally.
Data Source
AI summary
Current generation circuitry for an Implantable Pulse Generator (IPG) is disclosed. The IPG comprises a plurality of PDACs and NDACs for souring currents to electrode nodes. The PDACs and NDACs can be configured as pairs to each provide stimulation in independent timing channels, or the PDACs can be combined and the NDACs can be combined to provide stimulation in a single timing channel. Further, the PDAC or NDAC can provide a plurality of source branch currents each of the same amplitude to the electrodes via a switch matrix, and pulse definition circuitry can be configured to always connect each of the source branch currents to one of the first one or more electrode nodes via the switch matrix.