Implantable Pulse Generator Current Control Architecture
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Solution Overview
Problem
Current implantable pulse generators (IPGs) for spinal cord stimulation systems face challenges in efficiently managing stimulation currents across multiple electrodes, leading to potential inefficiencies and discomfort due to the limitations in current resolution and distribution.
Innovation Solution
The improved IPG architecture incorporates a microcontroller-integrated ASIC with pulse definition circuits and Digital-to-Analog Converter (DAC) pairs, allowing for precise control of stimulation currents across electrodes, enabling flexible current distribution and higher resolution modes to optimize therapy delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional separate microcontroller and ASIC architecture is used, then device functionality is achieved, but current resolution and control precision are insufficient
Solution Approach 1:
The patent merges the microcontroller and ASIC into a single integrated circuit device. The microcontroller includes an ASIC module embedded within it, allowing shared resources such as memory, processing units, and communication interfaces. This integration reduces the number of separate components while maintaining enhanced current resolution capabilities through the combined architecture.
Solution Approach 2:
The integrated microcontroller-ASIC architecture provides multi-functionality by combining general-purpose microcontroller capabilities with specialized ASIC functions for precise current control. The system can perform both high-level control operations and low-level stimulation signal generation within a single device, improving current resolution without requiring multiple separate components.
2Adaptability or versatility
If multiple separate ICs are used for current control, then current distribution flexibility is improved, but device size and power consumption increase
Solution Approach 1:
The patent combines multiple separate ICs into a single integrated microcontroller-ASIC device. The ASIC module within the microcontroller handles specialized current control functions while sharing common infrastructure such as power supply, memory, and processing resources. This reduces the total number of active components and interconnections, thereby lowering overall power consumption while maintaining current distribution flexibility.
Solution Approach 2:
The integrated architecture provides universal functionality for current control through the ASIC module embedded in the microcontroller. The system can dynamically allocate current to multiple electrodes with flexible distribution patterns while using a single power-efficient device, eliminating the need for multiple separate power-consuming ICs.
3Manufacturing precision
If higher resolution DAC pairs are implemented, then stimulation precision is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent integrates high-resolution DAC pairs within the ASIC module of the microcontroller rather than using separate external DAC components. This integration allows for optimized manufacturing processes where the DAC circuits are fabricated using standard semiconductor manufacturing techniques as part of the ASIC fabrication process, reducing overall manufacturing complexity despite the high precision requirements.
Solution Approach 2:
The patent replaces potential mechanical adjustment mechanisms for current control with integrated electronic DAC circuits fabricated in the ASIC. This substitution of electronic control for mechanical adjustment simplifies manufacturing while achieving high stimulation precision through digital-to-analog conversion within the integrated circuit.
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 solution enhances the precision and efficiency of current delivery, allowing for more nuanced and comfortable treatment of conditions like chronic pain by enabling finer control over stimulation parameters, thereby improving patient outcomes.
Implementation Method 1
The improved IPG architecture incorporates a microcontroller-integrated ASIC with pulse definition circuits and Digital-to-Analog Converter (DAC) pairs, allowing for precise control of stimulation currents across electrodes
Data Source
AI summary
An implantable pulse generator (IPG) is disclosed having a plurality of electrode nodes, each electrode node configured to be coupled to an electrode to provide stimulation pulses to a patient's tissue. The IPG includes a digital-to-analog converter configured to amplify a reference current to a first current specified by first control signals; a first resistance configured to receive the first current, wherein a voltage across the first resistance is held to a reference voltage at a first node; a plurality of branches each comprising a second resistance and configured to produce a branch current, wherein a voltage across each second resistance is held to the reference voltage at second nodes; and a switch matrix configurable to selectively couple any branch current to any of the electrode nodes via the second nodes.