Segmented Current Output Architecture for Implantable Stimulators

Solution Overview

Problem

Current Spinal Cord Stimulation (SCS) systems face inefficiencies in their output current source/sink architecture, leading to unnecessary power loss and wasteful use of space due to dedicated circuitry for each electrode, with shared nodes between source and sink circuitry potentially acting as both, causing voltage drops and unused circuitry.

Innovation Solution

A current output architecture where source and sink circuitry are divided into stages with switch banks, allowing current sourcing or sinking to any electrode, with no shared nodes prior to electrode connection, enabling scalable current output and global control through a digital-to-analog converter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If dedicated current source and sink circuitry is provided for each electrode, then each electrode can independently source or sink current, but the device consumes more power and occupies more space due to unused circuitry

Engineering Contradiction:

Improveelectrode current control capabilityVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The current source and sink circuitry are divided into multiple stages, with each stage capable of selectively connecting to any electrode through switch banks. This segmentation allows the system to provide dedicated current control capability to each electrode while sharing the underlying circuit stages, thereby reducing power consumption and space occupation compared to having fully dedicated circuitry for each electrode.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each stage of the current source/sink circuitry is designed to be universal, capable of sourcing or sinking current to any electrode through the switch banks. This multi-functionality allows a single stage to serve multiple electrodes at different times, eliminating the need for dedicated circuitry for each electrode and reducing overall power consumption and device size.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If dedicated current source and sink circuitry is provided for each electrode, then each electrode can independently source or sink current, but the device layout becomes less efficient and space is wasted

Engineering Contradiction:

Improveelectrode current control capabilityVSAvoiddevice layout space

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The current source and sink circuitry are divided into multiple stages, with each stage capable of selectively connecting to any electrode through switch banks. This segmentation allows the system to provide dedicated current control capability to each electrode while sharing the underlying circuit stages, thereby reducing power consumption and space occupation compared to having fully dedicated circuitry for each electrode.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple current source/sink stages are merged into a shared architecture that serves all electrodes. Instead of having separate dedicated circuitry for each electrode, the patent combines the circuit stages and uses switch banks to route current to the appropriate electrode, significantly reducing the overall device layout space while maintaining full electrode control capability.

Inventive Principle:

Principle #5Merging (Combining)

3Device complexity

If current source and sink circuitry share common nodes, then circuit complexity is reduced, but voltage drops occur and circuit performance deteriorates

Engineering Contradiction:

Improvecircuit architecture simplicityVSAvoidvoltage stability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The current source and sink circuitry are divided into multiple stages, with each stage capable of selectively connecting to any electrode through switch banks. This segmentation allows the system to provide dedicated current control capability to each electrode while sharing the underlying circuit stages, thereby reducing power consumption and space occupation compared to having fully dedicated circuitry for each electrode.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS8606362B2Current output architecture for an implantable stimulator device

Publication Date: 2013.12.10 BOSTON SCI NEUROMODULATION CORP

AI summary

Disclosed herein are current output architectures for implantable stimulator devices. Current source and sink circuitry is divided into a plurality of stages, each of which is capable via an associated switch bank of sourcing or sinking an amount of current to or from any one of the electrodes of the device. The current source circuitry is distinct from the current sink circuitry, and the two share no common circuit nodes prior to connection to the electrodes. In other words, the current source circuitry and the current sink circuitry do not share a common node other than the electrodes. Each stage is preferably formed of a current mirror for receiving a reference current and outputting a scaled version of current to that stage's switch bank. The scalar at each stage can be set by wiring a desired number of output transistors in parallel. Preferably, the reference current to the current mirrors in the stages is controllable via a digital-to-analog converter (DAC), to globally control the overall magnitude of the current supply to the electrodes.