Implantable Stimulator Voltage Monitoring for Compliance Control

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Solution Overview

Problem

Implantable nerve stimulation devices face challenges in managing battery power consumption, as insufficient supply voltage can hinder circuit operation, while excessive voltage wastes battery life, necessitating efficient voltage regulation to ensure optimal performance.

Innovation Solution

Incorporating a voltage monitoring circuit and programmable voltage regulator within the implantable device, controlled by a processor, to adjust the supply voltage to the current-generating circuit, ensuring it delivers the requested current while minimizing unnecessary power drain, using a current mirror circuit and comparator to detect and respond to voltage compliance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the supply voltage is increased to ensure proper circuit operation, then the reliability of circuit operation is improved, but the battery power consumption increases

Engineering Contradiction:
Improvecircuit operation reliabilityVSAvoidbattery power consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements dynamic voltage regulation by continuously monitoring the compliance voltage across the current-generating circuit and adjusting the supply voltage in real-time. The voltage regulator transitions from a static high-voltage supply to a dynamic system that adapts voltage levels based on actual circuit needs, thereby ensuring reliable operation while minimizing power consumption.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs a feedback mechanism where the compliance voltage is monitored and used to control the voltage regulator. This closed-loop feedback ensures that the supply voltage is maintained at the minimum level necessary for proper circuit operation, preventing both under-voltage conditions (which would compromise reliability) and over-voltage conditions (which would waste battery power).

Inventive Principle:
Principle #23Feedback

2Duration of action of moving object

If the supply voltage is decreased to conserve battery power, then the battery life is extended, but the circuit operation may become unreliable

Engineering Contradiction:
Improvebattery lifeVSAvoidcircuit operation reliability
Core Design Contradiction:
Duration of action of moving objectVSReliability

Solution Approach 1:

The system dynamically adjusts the supply voltage based on the actual compliance voltage requirements of the current-generating circuit. Rather than using a fixed low voltage that might compromise circuit operation, the voltage is continuously adapted to maintain the minimum necessary level for reliable circuit function while extending battery life through optimized power delivery.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The feedback loop monitors the compliance voltage across the current-generating circuit and adjusts the supply voltage accordingly. This ensures that the circuit receives sufficient voltage for reliable operation while avoiding excessive voltage that would deplete the battery unnecessarily, thus extending battery life without compromising reliability.

Inventive Principle:
Principle #23Feedback

3Ease of operation

If a fixed high voltage is supplied to the current-generating circuit, then the circuit operation is simplified, but unnecessary battery power is wasted

Engineering Contradiction:
Improvecircuit operation simplicityVSAvoidbattery power waste
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The patent replaces the static fixed high-voltage supply with a dynamic voltage regulation system that adapts the supply voltage to the actual needs of the current-generating circuit. This dynamic approach maintains circuit operation simplicity while eliminating the energy waste associated with providing consistently high voltage when lower levels would suffice.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the voltage parameter dynamically based on the compliance voltage conditions. Instead of maintaining a constant high voltage, the supply voltage is adjusted to match the actual requirements of the circuit, thereby reducing energy loss while keeping the circuit operation straightforward through automated voltage adaptation.

Inventive Principle:
Principle #35Parameter changes

4Use of energy by moving object

If voltage monitoring circuitry is added to regulate supply voltage, then battery power management is improved, but the device complexity increases

Engineering Contradiction:
Improvebattery power managementVSAvoiddevice complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The voltage monitoring and regulation functionality is integrated into the existing implantable device architecture, allowing the same circuitry to serve multiple functions. The compliance voltage monitoring is incorporated into the existing control system, and the voltage regulator works in conjunction with existing circuit components, thereby improving battery power management while minimizing the increase in device complexity through multi-functional integration.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent introduces a voltage regulator as an intermediary component between the battery and the current-generating circuit. This intermediary element manages the voltage delivery, providing precise power control without requiring complex monitoring systems throughout the entire device. The regulator acts as a dedicated component that simplifies the overall system architecture while achieving improved battery power management.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 effectively manages battery power by maintaining sufficient voltage for circuit operation while preventing unnecessary battery depletion, ensuring consistent and efficient therapeutic current delivery to the electrodes.

Implementation Method 1

a comparator that compares the compliance voltage to a reference voltage and that generates an output signal when the compliance voltage is not sufficient to allow the current mirror circuit to produce the requested current

Methodology Applied
Scientific EffectVoltage comparison: Ohm's Law

Implementation Method 2

a current mirror circuit that produces a requested current

Methodology Applied
Scientific EffectCurrent mirroring: Ohm's Law

Implementation Method 3

a voltage regulator that adjusts the compliance voltage supplied to the current-generating circuit

Methodology Applied
Scientific EffectVoltage regulation: Ohm's Law

Data Source

PatentEP3374019B1Controller for nerve stimulation circuit and associated systems and methods
Publication Date: 2021.12.22 NEVRO CORP
  • EP3374019B1 patent drawingFigure 1
  • EP3374019B1 patent drawingFigure 2
  • EP3374019B1 patent drawingFigure 3

AI summary

Disclosed is a voltage monitoring circuit for use in detecting if a voltage supplied to current-generating circuit is sufficient to allow the current-generating circuit to produce a desired current. In one embodiment the circuit is designed for use in an implantable device that is configured to deliver therapeutic pulses to a patient. The voltage monitoring circuit is configured to produce a signal if a supplied voltage is insufficient to allow a current-generating circuit to deliver a requested current to a set of electrodes. In one embodiment, the voltage monitoring circuit detects a change in a difference between the voltage at a node in the current- generating circuit and the supplied voltage.