Time Synchronization for Powered Accessories
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electronic devices often lose accurate time information when their power sources become detached or unavailable, leading to the need for quick and reliable time synchronization upon reconnection or restoration of power.
Innovation Solution
The system includes an electronic device and a powered accessory that communicate using network time protocol packets to update internal clocks, with the electronic device sending requests to both the powered accessory and a network time protocol server to ensure accurate timekeeping, and the powered accessory updates its real-time clock based on received information, while also detecting potential resets to set an uncertainty value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the electronic device uses an internal clock that loses time when power is unavailable, then the device can operate independently without continuous power, but the time information becomes inaccurate after power detachment or discharge
Solution Approach 1:
The system performs preliminary time synchronization actions by storing time information in non-volatile memory before power loss occurs. Upon power restoration, the device retrieves this stored time information to quickly re-synchronize the internal clock without requiring extensive time to reacquire accurate time, thus resolving the contradiction between operating independently and maintaining time accuracy.
2Speed
If the device quickly retrieves time from the powered accessory upon reconnection, then time synchronization speed improves, but the device cannot verify the accuracy of the time information received
Solution Approach 1:
The system implements feedback mechanisms where the electronic device compares time information received from the powered accessory with time information obtained from network time protocol servers. This cross-validation feedback loop allows the device to verify the reliability of time information while maintaining quick synchronization capabilities, resolving the contradiction between speed and reliability.
3Measurement precision
If the device sends time update requests to both the powered accessory and network time protocol server, then time accuracy improves, but the communication overhead and power consumption increase
Solution Approach 1:
The system applies partial action by selectively querying time sources based on availability and reliability conditions. Instead of continuously querying both the powered accessory and NTP server, the device performs partial queries only when necessary - such as when the powered accessory is connected or when network connectivity is available - thereby reducing unnecessary power consumption while maintaining time accuracy through targeted synchronization actions.
Data Source
AI summary
An electronic device can receive power from a powered accessory and can include a first communication system that communicates with the powered accessory; an internal clock; and a first processing system. Upon connection of the electronic device to the powered accessory, the first processing system can send a time update request to the powered accessory and can update the internal clock based on a time update received from the powered accessory. The powered accessory can include an energy storage device that delivers power to the electronic device; a second communication system that communicates with the electronic device; a real time clock; and a second processing system. Upon connection of the electronic device to the powered accessory and receiving the time update request from the electronic device the processing system can send the time update to the electronic device.