Charging Circuit Voltage Adaptation for Rugged Tablets

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Solution Overview

Problem

Rugged tablets face challenges in charging due to varying car battery voltages (10.8-19 volts), which cannot be efficiently converted by simple resistive voltage dividers, leading to the need for expensive charging chips supporting broad voltage range inputs.

Innovation Solution

A charging circuit utilizing a linear regulator to convert broad voltage range inputs into a fixed indication voltage, followed by a voltage divider circuit to generate a frequency response for a charger, allowing a common charger chip to provide charge current within a sensible range, reducing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a simple resistive voltage divider is used to convert power voltage, then the device complexity is reduced, but the adaptability to broad voltage range (10.8-19V) is insufficient

Engineering Contradiction:

Improvecharging circuit complexityVSAvoidvoltage range adaptability

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent introduces an intermediary voltage detection mechanism that measures the actual power voltage and uses this information to dynamically adjust the charging parameters. This mediator allows the simple resistive voltage divider to work effectively with broad voltage ranges by adapting the charging behavior based on detected voltage levels, rather than requiring a complex charging chip to handle all voltage conversions directly.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the operational parameters of the charging circuit based on the detected power voltage. When the power voltage varies within the 10.8-19V range, the circuit adjusts charging current and voltage thresholds dynamically, allowing a simple charging circuit structure to adapt to different voltage inputs without requiring expensive broad-range charging chips.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If a charging chip supporting broad voltage range input is used, then the voltage range adaptability is improved, but the cost increases

Engineering Contradiction:

Improvevoltage range adaptabilityVSAvoidmanufacturing cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent replaces the expensive broad-range charging chip with a combination of inexpensive components: a standard charging chip, simple resistive voltage dividers, and basic voltage detection circuitry. While individual components have limited voltage ranges, their coordinated operation through parameter changes achieves broad voltage adaptability at much lower cost.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent segments the voltage handling function across multiple simple components rather than using one complex broad-range chip. The voltage detection circuit, resistive dividers, and charging chip each handle specific voltage ranges or functions, working together to achieve overall broad voltage support through functional segmentation.

Inventive Principle:

Principle #1Segmentation

3Manufacturing precision

If a fixed charging voltage is used, then the manufacturing precision is improved, but the adaptability to varying power voltage is reduced

Engineering Contradiction:

Improvecharging voltage precisionVSAvoidpower voltage variation tolerance

Core Design Contradiction:

Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent transitions from a static fixed-voltage charging approach to a dynamic charging system that adjusts parameters in real-time based on detected power voltage. The charging circuit monitors input voltage and dynamically modifies charging current and voltage thresholds, maintaining precise charging control across varying power voltage conditions through adaptive parameter changes.

Inventive Principle:

Principle #15Dynamics

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

Enables cost-effective charging of rugged tablets by using a linear regulator and voltage divider circuit to convert broad voltage inputs into a fixed voltage, allowing the use of cheaper charger chips, ensuring reliable power supply across varying voltage scenarios.

Implementation Method 1

a linear regulator, for converting a power voltage into a first indication voltage

Methodology Applied

Scientific EffectLinear regulation:

Implementation Method 2

a voltage divider circuit, electrically coupled to the linear regulator, for generating a frequency response to convert the first indication voltage into a second indication voltage

Methodology Applied

Scientific EffectVoltage division: Ohm's Law

Data Source

PatentUS10135280B2Charging circuit and electronic device

Publication Date: 2018.11.20 WISTRON CORP

AI summary

A charging circuit for providing a charge current sent to a battery is disclosed. The charging circuit includes a linear regulator for converting a power voltage into a first indication voltage; a voltage divider circuit for generating a frequency response to convert the first indication voltage into a second indication voltage; and a charger for providing the charge current sent to the battery when the second indication voltage is within a sensible range, wherein the power voltage is within a broad voltage range, and the first indication voltage is fixed.