Capacitor-Based Time Tracking Without Backup Battery
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Solution Overview
Problem
Devices relying on real-time clocks often fail to maintain accurate timekeeping when the main power source is unavailable, as they typically require an oscillator that stops functioning without power, leading to device degradation or failure, and incorporating backup batteries can be expensive and difficult.
Innovation Solution
A system utilizing a capacitor as a time component to track elapsed time without an oscillator, allowing the real-time clock to resume operation when power is restored, eliminating the need for a backup battery by using the capacitor to store and discharge energy, and a controller to determine elapsed time through calibration and restart modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a backup battery is provided to maintain real-time clock operation during power loss, then timekeeping reliability is improved, but device cost and complexity increase
Solution Approach 1:
The patent extracts the time measurement function from the oscillator circuit and implements it using only the RTC capacitor and controller. By removing the oscillator component and using purely capacitive discharge characteristics to measure time, the system eliminates the need for a backup battery while maintaining timekeeping reliability during power loss events.
Solution Approach 2:
The patent replaces the mechanical/electronic oscillator system with an electrical capacitive discharge system. Instead of using an oscillator that requires power to maintain frequency, the system uses the natural discharge characteristics of the RTC capacitor through a resistor, measuring time based on voltage decay over time. This substitution eliminates moving parts and complex power management requirements.
2Reliability
If a backup battery is provided to maintain real-time clock operation during power loss, then timekeeping reliability is improved, but manufacturing difficulty increases
Solution Approach 1:
The patent extracts the time measurement function from the oscillator circuit and implements it using only the RTC capacitor and controller. By removing the oscillator component and using purely capacitive discharge characteristics to measure time, the system eliminates the need for a backup battery while maintaining timekeeping reliability during power loss events.
Solution Approach 2:
The patent uses the RTC capacitor, which is a standard, inexpensive component already present in most RTC circuits, to perform the time measurement function. The capacitor naturally discharges when power is removed, and this discharge characteristic is used to measure elapsed time. This approach uses a cheap, readily available component instead of requiring an expensive backup battery.
3Measurement precision
If an oscillator is used to track time, then time measurement precision is improved, but energy consumption increases causing failure during power loss
Solution Approach 1:
The patent uses the periodic discharge characteristic of the capacitor through a resistor to measure time. The voltage across the capacitor decreases in a predictable periodic manner according to the RC time constant, allowing the controller to measure elapsed time by sampling the voltage at known intervals or by measuring the time to reach specific voltage thresholds.
Solution Approach 2:
The patent replaces the mechanical/electronic oscillator system with an electrical capacitive discharge system. Instead of using an oscillator that requires power to maintain frequency, the system uses the natural discharge characteristics of the RTC capacitor through a resistor, measuring time based on voltage decay over time. This substitution eliminates moving parts and complex power management requirements.
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
Enables reliable timekeeping without a backup battery, reducing costs and complexity by using a capacitor to store energy and a controller to accurately determine elapsed time, ensuring device operation resumes correctly when power is restored.
Implementation Method 1
the time component is a capacitor or time capacitor that remains connected to the RTC
Implementation Method 2
When the system is in the OFF mode, the main supply is switched off by the switch component and the charge present on the capacitor drains through the RTC
Data Source
AI summary
A system utilizing time tracking is disclosed. The system includes a real time clock, a time component, and a controller. The real time clock is configured to track time. The time component is configured to measure a time value without an additional power source. The controller is configured to determine an elapsed time using the time value and calibration information and to update the real time clock using the elapsed time in a restart mode.