Dual-Range Sense Amplifier Circuit for Neural Artifact Rejection

Solution Overview

Problem

Existing implantable neurostimulator devices face challenges in accurately sensing neural responses due to stimulation artifacts, which can saturate the sense amplifier circuitry and make it difficult to resolve small neural signals.

Innovation Solution

The implementation of a differential sensing mechanism and DC offset compensation circuitry to mitigate the effect of stimulation artifacts, allowing for the use of high and low-voltage sense amplifiers based on signal magnitude, and a DC-blocking capacitor to stabilize the common mode voltage, enabling effective neural response sensing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If high-voltage sense amplifiers are used to handle large stimulation artifacts, then the ability to process stimulation artifacts is improved, but the noise performance deteriorates

Engineering Contradiction:

Improvestimulation artifact handlingVSAvoidneural signal detection precision

Core Design Contradiction:

Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The system dynamically switches between high-voltage and low-voltage sense amplifiers based on the magnitude of the common-mode voltage. When stimulation artifacts are detected (high common-mode voltage), the high-voltage amplifier is selected to handle the large signals. When artifacts are absent (low common-mode voltage), the low-voltage amplifier is selected for its superior noise performance and precision in detecting small neural signals.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the operating voltage parameter of the sense amplifier based on the signal conditions. The monitoring circuitry detects the common-mode voltage level and selects the appropriate amplifier voltage range, effectively adapting the electrical parameters of the sensing system to match the current operational requirements.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If low-voltage sense amplifiers are used for better neural signal precision, then measurement precision is improved, but the ability to handle stimulation artifacts deteriorates

Engineering Contradiction:

Improveneural signal detection precisionVSAvoidstimulation artifact handling

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The system dynamically switches between high-voltage and low-voltage sense amplifiers based on the magnitude of the common-mode voltage. When stimulation artifacts are detected (high common-mode voltage), the high-voltage amplifier is selected to handle the large signals. When artifacts are absent (low common-mode voltage), the low-voltage amplifier is selected for its superior noise performance and precision in detecting small neural signals.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the operating voltage parameter of the sense amplifier based on the signal conditions. The monitoring circuitry detects the common-mode voltage level and selects the appropriate amplifier voltage range, effectively adapting the electrical parameters of the sensing system to match the current operational requirements.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If dual amplifier circuitry is implemented to handle both high and low voltage signals, then adaptability is improved, but device complexity increases

Engineering Contradiction:

Improvevoltage range adaptabilityVSAvoidsense amplifier circuitry complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention implements a universal sense amplifier system that can operate in multiple voltage modes (high-voltage and low-voltage) using a single amplifier circuitry with selectable operating ranges. The monitoring circuitry and switching mechanism enable the same physical hardware to adapt its voltage operating range based on the signal conditions, achieving multi-functionality without requiring completely separate amplifier circuits for each voltage range.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentEP4433150B1Circuitry to assist with neural sensing in an implantable stimulator device in the presence of stimulation artifacts

Publication Date: 2026.03.11 BOSTON SCI NEUROMODULATION CORP

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AI summary

Sense amplifier (amp) circuitry for an implantable stimulator device is disclosed useful for sensing neural responses or other voltages in a patient's tissue. The sense amp circuitry comprises a low-voltage and a high-voltage sense amp circuit, either of which may be selected based on an assessment of the magnitude of the voltage at either or both of the inputs connected to selected sensing electrodes. The assessed magnitude, as determined by monitoring circuitry, can be processed by an algorithm to select use of one of the sense amp circuits, selecting the low-voltage sense amp circuit when the magnitude(s) are lower, and the high-voltage sense amp circuit when the magnitude(s) are higher. Furthermore, DC offset compensation circuitry is disclosed to equate the DC levels of the inputs, which may only operate when the high-voltage sense amp is selected.