Variable Resistor Detection Circuit for Battery Capacity Measurement

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Solution Overview

Problem

Current electronic terminals face inaccuracies in battery capacity measurement, leading to poor accuracy in estimating remaining battery life, particularly when users engage in resource-intensive activities like watching multimedia or gaming, due to large errors in existing estimation methods.

Innovation Solution

A detection circuit with a variable resistor and associated components that dynamically adjust resistance values based on real-time voltage differences and temperature, allowing for precise calculation of current and battery capacity, thereby improving the accuracy of remaining working time estimation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a sampling resistor with fixed resistance value is used in the charging and discharging circuit, then the system working current can be detected, but the measurement precision deteriorates when the current exceeds the working current range due to voltage saturation

Engineering Contradiction:
Improvebattery capacity measurement accuracyVSAvoidworking current range adaptability
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent applies the dynamics principle by transforming the fixed resistance value sampling resistor into a variable resistance value sampling resistor. The resistance value dynamically adjusts based on the detected system working current magnitude, allowing the sampling circuit to maintain optimal measurement precision across different current ranges. When current is small, resistance is higher for precise measurement; when current is large, resistance decreases to prevent voltage saturation while maintaining measurement capability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by modifying the resistance value parameter of the sampling resistor based on the detected current magnitude. The resistance value is changed from a fixed parameter to a variable parameter that adapts to different working conditions, thereby extending the measurable current range while maintaining measurement precision throughout the extended range.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If the resistance value of the sampling resistor is increased to improve current detection precision, then the current measurement accuracy improves, but the system power consumption increases

Engineering Contradiction:
Improvecurrent detection accuracyVSAvoidsystem power consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent applies dynamics by making the sampling resistor value variable rather than fixed. The resistance dynamically adapts to the current magnitude: higher resistance values are used when current is small to maintain precision without excessive power loss, while lower resistance values are used when current is large to reduce power consumption. This dynamic adjustment resolves the contradiction between precision and power consumption.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the resistance parameter from static to variable, allowing the system to optimize the trade-off between measurement precision and power consumption based on actual operating conditions. The resistance value parameter is adjusted according to current magnitude, achieving high precision when needed while minimizing power loss during normal operation.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If a fitting algorithm is used to estimate battery capacity based on battery voltage and temperature, then the device complexity is reduced, but the measurement precision deteriorates due to large errors

Engineering Contradiction:
Improvedetection circuit complexityVSAvoidbattery capacity estimation accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies dynamics by implementing a variable resistance sampling circuit that actively adapts to different operating conditions, replacing the passive fitting algorithm approach. This dynamic circuit adjustment maintains measurement precision across varying current ranges without requiring complex algorithms, thus resolving the contradiction between simplicity and precision.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent substitutes the software-based fitting algorithm with a hardware-based variable resistance sampling circuit. This mechanical/electrical substitution provides more accurate real-time measurements through physical circuit behavior rather than mathematical estimation, achieving higher precision while keeping the device relatively simple through analog circuit design.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 solution enhances the precision of battery capacity measurement and remaining working time estimation, ensuring accurate detection of current and electric quantity, which improves user experience by providing reliable battery life estimates.

Implementation Method 1

depending on the system charging and discharging current and the battery temperature acquired from the sampling resistor, and an integral algorithm is used to calculate the battery capacity. With this scheme, the working current range of this sampling resistor must be limited between 5 mA ∼ 2 A, according to the Ohm's law

Methodology Applied
Scientific EffectOhm's law: Ohm's Law

Data Source

PatentEP2827161B1Detection circuit and electronic terminal
Publication Date: 2019.10.02 ZTE CORP
  • EP2827161B1 patent drawingFigure 1
  • EP2827161B1 patent drawingFigure 2~3

AI summary

Disclosed are a detection circuit and an electronic terminal. The detection circuit is applied in the electronic terminal and configured to detect a real-time working current of the electronic terminal. The circuit comprises: a resistor (101), configured to comprise a first end and a second end, wherein the resistance value of the resistor (101) is variable; a sampling unit, configured to be connected with both ends of the resistor (101) and collect voltages at both ends of the resistor (101); a first memory (103), configured to store a current calculating method and an electric quantity calculating method; a data processing control unit (104), configured to be connected with the sampling unit and the first memory (103), calculate a voltage difference between the both ends of the resistor (101) according to the voltages at the both ends of the resistor (101), and call the current calculating method and the electric quantity calculating method to acquire a current value and an electric quantity value according to the voltage difference and the resistance value of the resistor (101); and a power supply device (105), configured to provide a stable power supply for the detection circuit.