Optical Sensor Drive Current Adaptation for Low Power Medical Monitoring
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Solution Overview
Problem
Medical monitoring devices, particularly those with limited power sources like wearable or wireless sensors, face challenges in maintaining reliable operation due to insufficient voltage or current levels, leading to potential system failures during critical medical procedures.
Innovation Solution
A method and system for dynamically testing and confirming sensor operating ranges by measuring available voltage or current, evaluating performance characteristics, and assessing them against minimum quality and safety standards, ensuring compatibility and safe operation in low power environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensor is driven at higher current levels to improve signal quality, then measurement precision is improved, but use of energy increases beyond available power
Solution Approach 1:
The patent applies dynamics by making the drive current variable rather than fixed. The system dynamically adjusts the drive current to the light emitting element based on available power levels, allowing optimal signal quality when power is sufficient and reduced current when power is limited, thus resolving the contradiction between measurement precision and energy consumption
Solution Approach 2:
The system changes the electrical parameters (current and voltage) of the light emitting element based on power availability. By measuring available voltage and current, the system determines appropriate drive parameters that ensure reliable operation within power constraints while maintaining adequate signal quality for physiological measurements
2Use of energy by moving object
If the sensor is driven at lower current levels to reduce power consumption, then use of energy is reduced, but measurement precision deteriorates due to insufficient signal quality
Solution Approach 1:
The system dynamically adapts the drive current to match available power levels. Rather than using a fixed low current, the system adjusts the current in real-time based on measured voltage and current availability, ensuring the lowest possible power consumption while maintaining adequate signal quality for the given power constraints
Solution Approach 2:
The system employs feedback by measuring the available voltage and current, comparing them against required levels, and adjusting the drive current accordingly. This closed-loop control ensures optimal balance between power consumption and signal quality, preventing both power exhaustion and insufficient measurement precision
3Measurement precision
If the sensor components are upgraded to newer generation with different electrical characteristics, then measurement precision and functionality are improved, but adaptability to older power supply systems deteriorates
Solution Approach 1:
The system changes its operating parameters (drive current, voltage levels) to adapt to different power supply characteristics. By measuring available power and adjusting parameters accordingly, the system can operate newer generation sensors with both old and new power supply systems, maintaining measurement precision across different generations of equipment
Solution Approach 2:
The system achieves universality by being capable of operating with multiple types of power supply systems (both older and newer generation). The initialization routine and adaptive drive current control allow the same sensor to function reliably across different power supply architectures, making the system versatile across equipment generations
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 ensures patient safety by rejecting incompatible sensors and maintaining a valid operating range, allowing for effective monitoring even in low power conditions, thereby preventing system failures during medical procedures.
Implementation Method 1
one or more light emitting elements, such as light emitting diodes (LEDs), that are configured to emit light at different wavelengths
Implementation Method 2
a detector, capable of detecting light from a patient
Data Source
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AI summary
Described herein are methods and apparatus monitoring a patient (40). In one example, a sensor (14) that is configured to detect physiological changes in a patient (40) is driven at a first current level and a subsequent sensor voltage is measured. Thereafter the current is varied to a second current level, and a next sensor voltage is measured. A next sensor voltage is projected based on the sensor voltage and the subsequent sensor voltage, and a third current level is identified that could produce the next sensor voltage. The third current level is compared to a threshold, and an alarm is produced in response thereto. The apparatus further includes elements in the sensor (14) that facilitate the method.