Battery Power Mode Control for Accurate Remaining Charge Detection
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Solution Overview
Problem
Existing electronic timepieces face inaccuracies in determining the remaining power of a secondary battery when multiple power feeders, such as solar cells and external power supplies, charge the battery, due to differences in current flow affecting voltage readings.
Innovation Solution
An electronic apparatus with a processor that uses distinct references and conversion tables to determine the remaining power of a secondary battery based on the power feeding mode, whether from solar cells or an external power source, accounting for temperature and voltage variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single reference is used to determine remaining power regardless of power feeder type, then the determination process is simple, but the measurement precision deteriorates due to different current characteristics from solar cells versus external power supplies
Solution Approach 1:
The patent segments the remaining power determination process by creating separate conversion tables for different power feeders (solar cells and external power supplies). Each conversion table contains references optimized for its specific power feeder's current characteristics, enabling accurate remaining power determination for each feeder type without interference from the other.
Solution Approach 2:
The patent applies local quality by using feeder-specific conversion tables that are tailored to the electrical characteristics of each power feeder. The determination processor selects and uses the appropriate conversion table based on which power feeder is currently active, ensuring that the reference values match the local electrical conditions of the active feeder.
2Reliability
If voltage-based remaining power determination is used, then the determination process is simple, but the reliability deteriorates when current flow differences between power feeders cause voltage variations
Solution Approach 1:
The patent segments the determination process by creating separate conversion tables for solar cell power and external power supply charging. Each table stores voltage-to-remaining-power conversion data that accounts for the specific current characteristics of its associated power feeder, eliminating the need for complex real-time current measurements while maintaining high reliability.
Solution Approach 2:
The patent applies preliminary action by pre-calculating and storing accurate conversion data in separate conversion tables for each power feeder type. These tables are prepared in advance based on the electrical characteristics of each feeder, so that during operation, the processor can directly use the appropriate table without performing complex real-time calculations or measurements.
3Measurement precision
If the electronic apparatus uses multiple conversion tables for different power feeders, then the measurement precision improves, but the device complexity increases due to additional memory and processing requirements
Solution Approach 1:
The patent segments the conversion data into separate tables for different power feeders, allowing each table to be optimized for its specific feeder's characteristics. This segmentation enables accurate remaining power determination while using only the necessary memory resources for each specific case, rather than requiring a single large table that must account for all possible conditions.
Data Source
AI summary
An electronic apparatus includes a secondary battery, a first power feeder, a second power feeder, and a processor. The first power feeder feeds power to the secondary battery. The second power feeder feeds power to the secondary battery at a current larger than a current fed by the first power feeder. The processor selects an operation mode of the electronic apparatus based on different reference values selected based on whether the first power feeder is feeding power to the secondary battery or the second power feeder is feeding power to the secondary battery.