Battery Fuel Gauge Current Summing for Multi-Charger Systems
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Solution Overview
Problem
Existing battery fuel gauge systems face challenges in accurately measuring total charge and discharge current due to the complexity of multi-path battery charging implementations, which complicates the determination of charging and discharging currents across multiple battery charger integrated circuits.
Innovation Solution
A fuel gauge system that comprises two or more battery chargers on different integrated circuits (ICs) coupled in parallel to a battery, where each charger generates a current signal indicative of its output, and a fuel gauge determines the total charging current by summing these signals, whether they are analog voltage, analog current, or digital signals, to provide accurate charging and discharging information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If multiple battery charger ICs are coupled in parallel to charge a battery, then power consumption and thermal losses are reduced, but accurate measurement of total charge and discharge current becomes difficult
Solution Approach 1:
The patent combines current information from multiple battery charger ICs by having each charger report its current output to a central fuel gauge IC, which then sums these individual current signals to determine the total battery current. This merging of information allows accurate measurement without requiring physical merging of current paths through a single measurement point.
Solution Approach 2:
The fuel gauge IC acts as an intermediary that collects current information from multiple battery charger ICs through communication interfaces. This mediator consolidates the distributed current data and provides an accurate total current measurement, resolving the measurement difficulty caused by the parallel charger configuration.
2Device complexity
If a single current sensing path is used for multiple battery chargers, then current measurement is simplified, but the system cannot reduce power consumption through multi-path charging
Solution Approach 1:
The patent segments the current measurement function by assigning individual current sensing capabilities to each battery charger IC while maintaining separate charging paths. Each charger IC independently measures its own output current and reports to the fuel gauge, allowing both simplified individual sensing and energy-efficient parallel charging operations.
Solution Approach 2:
The patent replaces the traditional mechanical/electrical approach of summing physical currents at a common point with an electronic information-based approach. Individual charger ICs digitally or analogously report their current outputs to the fuel gauge, which computationally determines total current, eliminating the need for complex physical current summation circuits.
3Measurement precision
If additional series resistance is introduced to measure total current in parallel charger configurations, then current measurement becomes possible, but power loss and thermal effects increase
Solution Approach 1:
The patent extracts the current measurement function from the main charging current path by having each battery charger IC independently sense and report its own current output. This removes the need for additional series resistance in the charging path, as measurement is performed at the source (each charger) rather than requiring current to flow through a common sensing resistor.
Solution Approach 2:
The fuel gauge IC serves as an intermediary that receives current information from each battery charger IC through low-power communication channels. This mediator calculates total current without requiring high-power series resistance elements in the charging path, thereby avoiding the power loss and thermal effects that would result from such resistance.
Data Source
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AI summary
In one embodiment, a fuel gauge system is described that comprises two or more battery chargers on different integrated circuits (ICs) coupled in parallel to a battery for charging the battery. Each battery charger IC generates a current signal indicative of current generated by said each battery charger IC into the same battery. A fuel gauge is responsible for accurately reporting the battery state of charge, based on a combination of voltage, current, and temperature information.