Charging Device Using Oxide Semiconductor Transistor for Low Power Consumption
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Solution Overview
Problem
Existing charging devices for storage batteries, such as lithium secondary batteries, face high power consumption due to the use of analog-digital converters, which is inefficient and increases energy costs.
Innovation Solution
A charging device that utilizes a voltage-to-current converter circuit, an oxide semiconductor transistor, and a comparator to determine the completion of charge without an analog-digital converter, reducing power consumption by using a resistive element and a capacitor to accumulate charge and generate a signal indicating charge completion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an analog-digital converter is used to convert analog charging current signals to digital signals for processing, then measurement precision and control accuracy are improved, but power consumption increases significantly
Solution Approach 1:
The patent extracts and eliminates the analog-digital converter from the charging device circuitry. By removing this high-power component, the invention achieves significant power consumption reduction while maintaining charging completion detection functionality through alternative analog circuitry including current accumulation circuits and voltage comparison methods.
Solution Approach 2:
The patent substitutes electronic analog processing (using operational amplifiers, integrators, and voltage comparators) to replace the need for analog-digital conversion and digital processing. This substitution maintains measurement precision for charging completion detection while avoiding the high power consumption associated with ADC operations and digital signal processing.
2Use of energy by moving object
If analog-digital converter is eliminated to reduce power consumption, then energy efficiency is improved, but device complexity may increase due to alternative circuit design
Solution Approach 1:
The patent employs operational amplifiers that perform multiple functions: current-to-voltage conversion, signal integration/accumulation, and voltage comparison. This multi-functionality reduces the need for separate dedicated circuits for each operation, thereby simplifying the overall circuit configuration while eliminating the ADC and reducing power consumption.
Solution Approach 2:
The patent combines current accumulation and voltage comparison functions into an integrated analog circuit system. By merging these functions into a coordinated analog processing chain using operational amplifiers and comparators, the invention reduces circuit complexity compared to having separate ADC, digital counter, and comparison logic circuits.
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
The solution enables a low-power-consumption charging device that accurately determines charge completion in storage batteries, reducing energy costs and enhancing efficiency by eliminating the need for analog-digital converters.
Implementation Method 1
A voltage-to-current converter circuit electrically connected to both terminals of the resistive element determines a potential difference between the terminals of the resistive element. The voltage-to-current converter circuit supplies a current (referred to as Is) which depends on the potential difference between the terminals of the resistive element.
Implementation Method 2
The other of the source and the drain of the transistor is electrically connected to a capacitor. When the transistor is on, the current Is flows between the source and the drain of the transistor and thus charge is accumulated in the capacitor.
Implementation Method 3
One terminal of the capacitor and the other of the source and the drain of the transistor are electrically connected to a first terminal of a comparator. The output potential of the comparator changes from a low-level potential VL to a high-level potential VH when the potential of the one terminal of the capacitor where charge is accumulated reaches the reference potential supplied to a second terminal of the comparator.
Data Source
AI summary
A charging device used for charging a storage battery includes a first circuit that generates a current which depends on a charging current of the storage battery; a second circuit in which charge is accumulated by periodical supply of the current which depends on the charging current; and a third circuit that outputs a signal indicating completion of charge of the storage battery when the potential of the second circuit reaches a reference potential. The second circuit includes a capacitor and a transistor in which an oxide semiconductor is used for a channel formation region. The transistor is turned on or off in response to a pulse signal input to a gate of the transistor. The capacitor accumulates charge when the current depending on the charging current flows through the transistor.