Active Discharge Pulses for Implantable Pulse Generator Charge Balance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Implantable pulse generators face issues with charge accumulation during constant current electrical stimulation, leading to pulse skewing and limited frequency due to passive discharge, which can result in inefficient power dissipation and potential hazards from unbalanced charge.
Innovation Solution
Active discharge pulses with opposite polarity and programmable amplitude and duration are implemented, reducing power dissipation by adjusting the driving voltage and load, ensuring efficient capacitive discharge and minimizing residual charge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If balanced pulses are used to prevent charge accumulation, then pulse skewing is prevented, but power consumption doubles
Solution Approach 1:
The pulse train is segmented into stimulation pulses followed by separate active discharge pulses with opposite polarity. This segmentation allows the system to prevent charge accumulation through targeted discharge pulses rather than requiring all pulses to be balanced, thereby reducing overall power consumption while maintaining pulse reliability.
Solution Approach 2:
Active discharge pulses are applied in advance or immediately after stimulation pulses to preemptively discharge accumulated charge on capacitive connections. This preliminary discharge action prevents charge skewing before it can affect subsequent stimulation pulses, eliminating the need for continuous balanced pulse sequences and reducing power consumption.
2Use of energy by moving object
If simple passive discharge is used, then power consumption is reduced, but discharge time increases and frequency is limited
Solution Approach 1:
The discharge process is made dynamic by using active electronic switching to control the discharge path and timing. Instead of relying on fixed passive RC time constants, the system actively manages discharge through controlled current paths, enabling faster discharge speeds while maintaining low power consumption and avoiding frequency limitations.
Solution Approach 2:
Active discharge circuits serve as intermediaries between the capacitive connections and ground, providing controlled discharge paths. These intermediary circuits enable faster discharge than passive methods by actively managing current flow, thereby increasing discharge speed without significantly increasing power consumption and avoiding frequency limitations.
3Device complexity
If simple passive discharge is used, then device complexity is reduced, but significant charge remains accumulated between pulses
Solution Approach 1:
The active discharge circuit automatically discharges accumulated charge on capacitive connections without requiring external intervention or complex control systems. The circuit self-regulates to maintain charge balance by detecting and discharging accumulated charge, thereby improving reliability while keeping the overall device complexity manageable through integrated design.
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 approach maintains efficient pulse delivery while reducing power consumption and preventing pulse skewing, ensuring safe and reliable operation of implantable pulse generators by actively managing capacitive discharge.
Implementation Method 1
power dissipation during active discharge is reduced
Data Source
AI summary
To avoid charge accumulation on capacitive connections to implanted electrodes during delivery of stimulation pulses, stimulation pulses are followed by active discharge pulses having opposite polarity of the stimulation pulses. The active discharge pulses preferably have at least one pulse attribute magnitude (e.g., duration, voltage, and/or current) different than a corresponding stimulation pulse and are preferably programmable. Approximately the same total net current flow is delivered during active discharge pulses as during the stimulation pulses, but in the opposite direction and optionally at a lower amplitude. In addition, by reducing the driving voltage and a variable load within the electrical path for delivery of the pulses, power dissipation during active discharge is preferably reduced.