Switched Capacitor Electrical Stimulation Device for Tissue Safety

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Solution Overview

Problem

Implantable electrical stimulators for medical applications face challenges with high power consumption, heat generation, and potential tissue damage due to inefficient power management and electrode charge accumulation, requiring innovative solutions for safer and more effective stimulation.

Innovation Solution

A switched capacitor-based electrical stimulation device that charges a plurality of capacitors with DC power and controls voltage levels and discharge patterns to minimize energy consumption and prevent tissue damage, utilizing a power module, capacitor module, charging module, and output module to manage and deliver electrical stimulation efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a constant voltage source and constant current source are used in conventional electrical stimulators, then the device can deliver stable electrical stimulation, but electric charges accumulate in the electrodes and tissues causing damage

Engineering Contradiction:

Improvesafe electrical stimulationVSAvoidelectric charge accumulation damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent employs periodic charging and discharging of capacitors in a switched capacitor circuit. The capacitors are charged during non-stimulation periods and discharged during stimulation periods, creating a periodic action that delivers electrical stimulation while allowing charge to be periodically removed from the system, preventing continuous charge accumulation in electrodes and tissues

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The switched capacitor circuit discards accumulated charge by periodically discharging the capacitors through the electrodes during stimulation phases. The charge is then recovered by recharging the capacitors during non-stimulation phases, creating a cyclic process that prevents harmful charge buildup while maintaining stimulation capability

Inventive Principle:

Principle #34Discarding and recovering

2Reliability

If high power is used to achieve effective stimulation, then stimulation efficacy is improved, but heat generation increases causing tissue damage

Engineering Contradiction:

Improvestimulation efficacyVSAvoidheat generation tissue damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The switched capacitor circuit operates in periodic cycles of charging and discharging. During the charging phase, power is drawn from the battery to charge capacitors. During the discharging phase, the stored energy is delivered to the electrodes. This periodic operation allows for efficient energy transfer while minimizing continuous power consumption and associated heat generation

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent changes the operating parameters by using voltage switching rather than continuous current regulation. The switched capacitor circuit switches between different voltage levels (charged and discharged states) to deliver stimulation, which improves power efficiency compared to conventional constant current sources that continuously consume power and generate heat

Inventive Principle:

Principle #35Parameter changes

3Reliability

If conventional DC-DC converter and constant current source are used, then electrical stimulation can be delivered, but power consumption is high reducing battery run time

Engineering Contradiction:

Improveelectrical stimulation deliveryVSAvoidbattery run time

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The switched capacitor circuit uses periodic charging and discharging of capacitors to deliver electrical stimulation. The capacitors are charged during non-stimulation periods and discharged during stimulation periods, creating a periodic action that delivers electrical stimulation while allowing charge to be periodically removed from the system, preventing continuous charge accumulation in electrodes and tissues

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

Inventive Principle:

Principle #34Discarding and recovering

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

The solution enables efficient power management, reduces heat generation, and enhances stimulation efficacy by sequentially charging and discharging capacitors, providing safer and more effective electrical stimulation with improved battery run time and reduced tissue damage.

Implementation Method 1

a capacitor module including a plurality of capacitors which is charged with the DC power

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS20230010500A1Switched capacitor-based electrical stimulation device and method

Publication Date: 2023.01.12 KOREA UNIV RES & BUSINESS FOUND

AI summary

Provided is a switched capacitor-based electrical stimulation device which supplies a direct current (DC) power, detects a charging voltage charged in any one of a plurality of capacitors, controls the DC power supplied to a capacitor module to repeat a charging level and a resting level according to a charging pattern when the charging voltage is lower than a target voltage, and outputs an electric current to electrodes which contact a human body based on an output pattern.