PPG Light-Emission Control for Accurate, Low-Power Wearable Sensing
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Solution Overview
Problem
Existing wearable devices face challenges in balancing power consumption and measurement accuracy of photoplethysmography (PPG) modules, particularly in varying environments and measurement targets like heart rate and blood oxygen detection.
Innovation Solution
A PPG control method that adapts light emitting modes and sampling rates based on current measurement environments and targets, using multiple LEDs and PDs to optimize power usage while ensuring accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the PPG module uses higher sampling frequency and luminous power to improve measurement accuracy, then measurement accuracy is improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic adjustment of sampling frequency and luminous power based on real-time motion state detection. The processor determines whether the device is in motion or rest state using motion sensors, and dynamically switches between high-power mode (higher sampling frequency and luminous power for motion states) and low-power mode (lower sampling frequency and luminous power for rest states), resolving the contradiction between measurement accuracy and power consumption
Solution Approach 2:
The patent changes key operating parameters (sampling frequency and luminous power) based on measured conditions. Specifically, it adjusts the sampling frequency of the PPG sensor and the luminous power of the LED according to the detected motion state, allowing the system to optimize measurement accuracy while minimizing power consumption by using appropriate parameter levels only when necessary
2Measurement precision
If the PPG module operates in high-power consumption mode to ensure measurement accuracy in all conditions, then measurement accuracy is maintained, but battery duration decreases
Solution Approach 1:
The patent implements periodic motion state detection and mode switching. The system periodically checks the motion state using motion sensors and alternates between high-power and low-power measurement modes based on the detected state, ensuring measurement accuracy is maintained during motion while extending battery duration during rest periods
Solution Approach 2:
The system automatically detects motion state and self-adjusts its operating mode without user intervention. The processor monitors motion sensors and autonomously switches between measurement modes, allowing the device to serve itself in optimizing the balance between measurement accuracy and battery duration
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
Reduces power consumption of PPG modules by adjusting light emitting devices and sampling rates according to user states, enhancing measurement accuracy and user experience.
Implementation Method 1
The PPG module includes a light-emitting diode (light-emitting diode, LED) and a photodiode (Photo-Diode, PD). Light emitted by the LED irradiates skin and then is reflected, and the reflected light is collected by the PD
Data Source
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AI summary
Embodiments of this application provide a PPG control method and apparatus, and an electronic device. The method is applied to an electronic device, the electronic device includes a PPG module, and the PPG module includes a light emitting module. The method includes: determining a current measurement environment and/or measurement target, where the measurement environment includes motion, rest, and sleep, and the measurement target includes a heart rate and blood oxygen; and determining a light emitting mode of the light emitting module based on the current measurement environment and/or measurement target. The method according to this embodiment of this application can reduce power consumption of the PPG module while ensuring measurement accuracy of the PPG module.