Solar-Powered Timepiece Voltage Thresholds for Battery Restoration
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Solution Overview
Problem
Electronic timepieces with solar panels face challenges in restoring secondary batteries to a normal charged state under low illumination conditions, leading to repeated cycles of battery voltage fluctuations and incomplete charging, which can prevent normal operation.
Innovation Solution
The electronic timepiece is configured with specific voltage thresholds for operation and display start, where the operation start voltage (1.2 V) is set lower than the display start voltage (2.2 V), allowing activation and gradual display initiation once the battery is sufficiently charged, including a CPU reset circuit and battery voltage detection to manage charging states and display notifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the electronic timepiece starts oscillation and display simultaneously from immediately after CPU reset when restoring the secondary battery, then the response speed is improved, but the consumed current exceeds the generated current of the solar panel causing repeated voltage fluctuations and failure to charge
Solution Approach 1:
The patent applies preliminary action by performing CPU reset and oscillation start before display activation. The system first restores the secondary battery to a charged state through CPU reset and oscillation initiation, then subsequently activates the display unit only after confirming sufficient battery charge. This sequential preliminary actions prevent simultaneous high current consumption that would cause voltage fluctuations and charging failure.
Solution Approach 2:
The patent segments the startup process into distinct phases: first phase includes CPU reset and oscillation start, second phase includes display activation. By dividing the startup sequence into separate stages rather than executing all functions simultaneously, the system manages current consumption progressively, ensuring the solar panel can sustain the operations without causing repeated voltage drops that would prevent charging.
2Loss of time
If the display unit is activated immediately after CPU reset, then the display responsiveness is improved, but the power consumption increases causing battery voltage to drop below the operation start voltage
Solution Approach 1:
The patent performs preliminary battery charging through CPU reset and oscillation start before activating the display unit. This preliminary action ensures the battery reaches sufficient charge level, allowing the display to activate without causing voltage drops below the operation start threshold, thus balancing responsiveness with power consumption.
Solution Approach 2:
The patent dynamically adjusts the startup sequence based on battery charge state. The display activation is conditioned on the battery reaching a sufficient charge level after preliminary oscillation start, creating a dynamic control mechanism that prevents power consumption from causing voltage drops below operational thresholds.
3Device complexity
If the operation start voltage is set equal to the display start voltage, then the system simplicity is improved, but the ability to restore battery smoothly under low illumination is worsened
Solution Approach 1:
The patent segments the voltage thresholds into two distinct levels: operation start voltage for CPU reset and oscillation start, and display start voltage for display activation. This segmentation allows the system to perform critical startup functions at a lower voltage threshold, then activate the power-intensive display only after the battery reaches a higher charge level, ensuring smooth battery restoration under low illumination conditions.
Solution Approach 2:
The patent changes the voltage parameter thresholds to create two distinct activation levels. By setting operation start voltage lower than display start voltage, the system enables gradual startup processes at lower voltages and reserves display activation for when sufficient battery charge is available, improving battery restoration reliability without significantly complicating the control logic.
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 configuration enables smooth and reliable restoration of secondary batteries to a normal charged state even under low illumination, ensuring the timepiece can resume normal operation without prolonged display blackout periods, providing clear charging status updates to the user.
Implementation Method 1
a solar panel configured to generate power upon reception of light
Data Source
AI summary
An electronic timepiece is operated with a power-supply voltage from a secondary battery charged with a voltage from a solar panel. An oscillation circuit generates and supplies a clock signal to a CPU when the voltage charged to the battery is lower than a first voltage. A reset circuit resets the CPU when the voltage charged to the battery does not exceed a second voltage higher than the first voltage, and cancels the reset of the CPU when the voltage charged to the second battery exceeds the second voltage. The CPU starts an operation when the voltage charged to the secondary battery exceeds the second voltage and the reset is cancelled, and performs a time-of-day display on a display unit when the voltage charged to the secondary battery is equal to or higher than a third voltage higher than the second voltage.