EMG Amplifier Charging During Irrelevant Segments
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Solution Overview
Problem
Existing measurement signal amplifiers for EMG sensors face issues with common-mode rejection during charging, leading to measurement inaccuracies and increased space and manufacturing costs due to the need for multiple modules or inefficient DC-DC converters, which also cause heat generation and discomfort for patients.
Innovation Solution
A measurement signal amplifier with a sensor interface, device interface, and computing unit that charges the energy store during diagnostically irrelevant segments of the EMG sensor signal, using a size-optimized capacitor and intermittent energy supply to minimize interference and reduce parasitic capacitance, ensuring accurate signal amplification without galvanic connection during charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If an energy storage device is charged continuously to ensure sufficient power supply, then the power availability is improved, but the common-mode rejection ratio deteriorates during charging
Solution Approach 1:
The patent implements periodic charging cycles where the energy storage device is charged during ECG-related time intervals (when measurement precision requirements are lower) and remains available during other periods. This periodic action allows the system to maintain both adequate power availability and acceptable common-mode rejection ratio by timing charging operations to coincide with periods when measurement precision is less critical.
2Measurement precision
If multiple modules with separate energy storage devices are used to maintain common-mode rejection during charging, then the common-mode rejection ratio is improved, but the device complexity and manufacturing costs increase
Solution Approach 1:
The patent segments the time intervals into different types (ECG-related vs. non-ECG-related) and applies different charging strategies to each segment. By temporal segmentation rather than spatial segmentation (multiple modules), the system maintains common-mode rejection ratio while avoiding the complexity and cost of multiple parallel modules with separate energy storage devices.
3Adaptability or versatility
If a DC-DC converter is used to provide power to the amplifier, then the power supply flexibility is improved, but the heat generation increases causing patient discomfort
Solution Approach 1:
The patent extracts the DC-DC converter from the immediate vicinity of the patient by placing it in an external device rather than integrating it directly into the amplifier positioned near the patient. This extraction maintains power supply flexibility while removing the heat-generating component from the patient contact area, thereby eliminating the harmful thermal effect.
4Use of energy by moving object
If the energy storage device is charged during relevant EMG signal segments, then the power availability is improved, but the measurement precision deteriorates due to charging interference
Solution Approach 1:
The patent converts the potentially harmful effect of charging interference by strategically timing charging operations to occur during ECG-related time intervals where measurement precision is already less critical. What would normally be a harmful interference (charging during signal acquisition) is transformed into a beneficial strategy by aligning charging with periods of lower measurement requirements, thus maintaining both power availability and signal accuracy.
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 provides improved common-mode rejection, reduced space requirements, lower manufacturing costs, and enhanced signal accuracy by charging the energy store during irrelevant signal segments, preventing interference with relevant EMG signals and minimizing heat generation.
Implementation Method 1
a measurement signal amplifier for amplifying an EMG sensor signal, comprising a sensor interface for receiving the EMG sensor signal, at least one device interface for receiving an electrical energy signal and for transmitting a processing signal, an electrically rechargeable energy storage device
Data Source
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Figure 3~4
AI summary
The invention relates to a measurement signal amplifier (1) for amplifying an EMG sensor signal (E), comprising a sensor interface (2) for receiving said EMG sensor signal (E), at least one device interface (3) for receiving an electrical energy signal and transmitting a processing signal (V), an electrically-rechargeable energy store (4), and at least one computing unit (5). Said computing unit (5) is designed to derive a processing signal (V) from the EMG sensor signal (E) and, depending on the EMG sensor signal (E) that is received by the sensor interface (2), to control charging of the energy store (4) by means of the electrical energy signal.