Sensor Hub Time Calibration for Mobile Power Management
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Solution Overview
Problem
Mobile devices equipped with sensors continuously generate samples, leading to prolonged CPU operation and reduced battery life due to the need for constant data collection and processing.
Innovation Solution
Implementing a microcontroller (MCU) as a sensor hub that fetches samples from sensors in batches, performs initial processing, and stores results, allowing the CPU to sleep longer and wake only when necessary, thereby reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the CPU continuously collects and processes sensor samples, then the processing functionality is maintained, but the battery life is reduced due to prolonged CPU operation
Solution Approach 1:
The patent introduces a sensor hub as an intermediary component between the sensors and the CPU. The sensor hub collects sensor samples, performs initial processing, and manages data buffering, allowing the CPU to operate in low-power states while maintaining processing functionality through periodic data retrieval from the sensor hub.
Solution Approach 2:
The patent divides the processing system into separate functional components: sensors generate data, the sensor hub processes and buffers data, and the CPU performs high-level processing only when needed. This segmentation allows each component to operate independently, enabling the CPU to sleep while the sensor hub continues basic operations.
2Measurement precision
If the CPU operates in full mode to process sensor data constantly, then data processing accuracy is maintained, but power consumption increases
Solution Approach 1:
The patent implements partial processing at the sensor hub level, where basic data collection and initial filtering occur without requiring full CPU operation. The CPU performs complete processing only when necessary, achieving adequate data accuracy while reducing power consumption through intermittent operation.
Solution Approach 2:
The sensor hub performs preliminary data processing, filtering, and buffering before data reaches the CPU. This preliminary action ensures that when the CPU does wake to process data, the information is already prepared and validated, maintaining accuracy while minimizing the duration of high-power CPU operation.
Data Source
AI summary
Methods and devices with sensor time calibration are provided. A representative device incorporates: a motion sensor having sensor circuitry and a first clock, the motion sensor being configured to generate and store sensor data samples at a predefined output data rate according the first clock; and a microcontroller, having circuitry, coupled to the motion sensor and being configured to fetch, during a predefined average time span, a sequence of the sensor data samples from the motion sensor and calculate a total number of the sensor data samples fetched. The microcontroller is further configured to provide a calibrated output data rate based on the total number of sensor data samples fetched and a reference time span, corresponding to a time span during which the sensor data samples were stored at the predefined output data rate, provided by a second clock.