Semiconductor Battery Protection Unit Multi-Functional Current Terminal
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Solution Overview
Problem
The existing semiconductor units for protecting secondary batteries, such as lithium ion batteries, face challenges in reducing test time during inspection and production while maintaining miniaturization, as current methods require additional terminals or increased chip size to accommodate test signals, leading to longer inspection times and increased costs.
Innovation Solution
A semiconductor unit that generates two test signals from the current detecting terminal's voltage, allowing for different tests without adding new terminals, by utilizing a test signal generating circuit that outputs a first test signal at a first negative voltage and a second test signal at a second negative voltage, which is lower, thereby shortening the delay time during testing and avoiding the need for additional terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a test terminal is added to apply test signals for shortening delay time during testing, then test time is shortened, but package size increases and existing small packages cannot accommodate the semiconductor unit
Solution Approach 1:
The current detecting terminal is made multi-functional by enabling it to serve both its original function of detecting charging/discharging current and the additional function of receiving test signals. The terminal structure is designed to accommodate multiple signal types (charging current, discharging current, and test signals) through a single interface, eliminating the need for separate test terminals and maintaining compact packaging.
Solution Approach 2:
The test signal input function is merged with the existing current detecting terminal. By combining the test signal reception capability with the current detection function in a single terminal, the patent avoids increasing the number of terminals and maintains the compact package size while still enabling rapid testing through shortened delay times.
2Adaptability or versatility
If the number of bonding pads is increased to provide test terminals, then test signals can be applied, but IC chip size increases and extra space or cost arises
Solution Approach 1:
The bonding pads connected to the current detecting terminal are made multi-functional to handle both normal operating signals (charging/discharging current) and test signals. This eliminates the need for additional dedicated test bonding pads, maintaining the original IC chip area while providing full test capability through the existing pad structure.
Solution Approach 2:
The test signal transmission function is merged into the existing bonding pad infrastructure. By utilizing the same bonding pads for both operational and testing purposes, the patent avoids increasing IC chip area while achieving adaptability for comprehensive testing through the unified signal path.
3Reliability
If delay time is set longer for overcharge detection, then false detection is prevented, but inspection time increases and mass production effect degrades
Solution Approach 1:
The delay time is made dynamic rather than fixed, allowing it to be adjusted based on the testing mode. During normal operation, a longer delay time maintains detection accuracy and prevents false positives. During manufacturing inspection, the delay time can be shortened to enable rapid testing and maintain mass production efficiency, with the system adapting its timing characteristics to the current operational context.
Solution Approach 2:
The delay time parameter is made changeable between different operational modes. By allowing the delay time to be modified based on whether the system is in normal operation or testing mode, the patent achieves both reliable detection (longer delay during operation) and high productivity (shorter delay during testing), resolving the contradiction between detection accuracy and mass production efficiency.
Data Source
AI summary
A semiconductor unit for protecting a secondary battery has a current detecting terminal converting a charging current to a negative voltage with respect to a negative electrode potential (ground potential) of the secondary battery when the secondary battery is charged, converting the charging current to a positive voltage with respect to the negative electrode potential (ground potential) of the secondary battery when the secondary battery is discharged, and detecting the charging/discharging current; and a test signal generating circuit generating a first test signal when the voltage of the current detecting terminal lowers to a first negative voltage which does not occur in a normal operation state of the semiconductor unit, and generating a second test signal when the voltage of the current detecting terminal lowers to a second negative voltage lower than the first negative voltage.