USB Port Smart Power Management via Inrush Current Detection

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Mobile communication devices often require different external battery adapters/chargers for each version, leading to environmental waste and inefficiency in charging, especially when a laptop's battery is inadequately charged, as the CPU consumes significant power even when idle, making it inefficient to charge devices like cellular telephones via USB ports.

Innovation Solution

A method that detects an inrush current condition in a laptop computer's USB port when a handheld device is connected, enabling a DC-to-DC converter to supply a regulated voltage without powering the CPU, allowing the laptop's battery to charge the handheld device without turning on the laptop, thus reducing energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the laptop computer is turned on to charge the handheld device through USB port, then the charging function is available, but the CPU consumes substantial amount of power even when idle

Engineering Contradiction:

Improvecharging availabilityVSAvoidbattery energy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent extracts the USB power supply function from the main CPU-powered system by implementing a separate battery-to-USB power path through a dedicated power management integrated circuit (PMIC). This allows the USB port to supply power to external devices independently of the CPU's operational state, enabling charging functionality while the laptop remains off and conserving battery energy.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The power management system is segmented into multiple independent power paths: one path for CPU operation and another path for USB power output. The USB power path includes its own voltage regulation and current control circuits that can operate autonomously from the CPU, allowing selective activation of charging functionality without powering the entire system.

Inventive Principle:

Principle #1Segmentation

2Ease of operation

If the USB port supplies power continuously to ensure always available charging, then charging convenience is improved, but the battery energy is depleted faster

Engineering Contradiction:

Improvecharging convenienceVSAvoidbattery energy loss

Core Design Contradiction:

Ease of operationVSLoss of energy

Solution Approach 1:

The patent implements feedback control through current sensing circuits that monitor the power draw at the USB port. Based on the detected current level, the system dynamically adjusts the power supply state - enabling power output when a device is connected and disabling it when no device is present. This feedback mechanism ensures charging convenience is available on-demand while preventing unnecessary energy depletion when not needed.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The USB power supply transitions from a static always-on state to a dynamic state that adapts based on connection status. The system uses detection circuits to sense when a device is connected to the USB port and activates power supply only during this period, creating a dynamic power management approach that balances convenience with energy conservation.

Inventive Principle:

Principle #15Dynamics

3Loss of energy

If the laptop remains off to conserve battery energy, then energy consumption is reduced, but the USB port cannot charge external devices

Engineering Contradiction:

Improvebattery energy conservationVSAvoidcharging functionality

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

Inventive Principle:

Principle #2Taking out (Extraction)

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 method enables efficient charging of handheld devices from a laptop's battery without powering the laptop, conserving energy and reducing environmental waste by utilizing the laptop's battery more effectively when external AC power is not available.

Implementation Method 1

the inrush current condition is detected by applying a regulated voltage onto a terminal of the USB port and determining whether a current flowing out of the USB port is larger than a predetermined current

Methodology Applied

Scientific EffectInrush current detection: Ohm's Law

Implementation Method 2

the inrush current condition is detected by applying a current source onto a terminal of the USB port and determining whether a voltage on the terminal of the USB port is lower than a predetermined voltage

Methodology Applied

Scientific EffectInrush current detection: Ohm's Law

Implementation Method 3

enabling a DC-to-DC converter of the first electronic device such that the DC-to-DC converter supplies a regulated voltage onto the USB port in response to the detection of the inrush current

Methodology Applied

Scientific EffectDC-to-DC conversion: Electromagnetic Induction

Data Source

PatentUS8084987B2USB port with smart power management

Publication Date: 2011.12.27 QORVO INT PTE LTD

AI summary

A method involves detecting an inrush current that flows out of a USB port of a first electronic device when a central processing unit (CPU) of the first electronic device is not being powered. The inrush current is detected by a novel inrush current detect circuit when a second electronic device is connected to the USB port. In one example, the first electronic device is a laptop computer having a battery and a USB DC-to-DC converter. The inrush current detect circuit enables the USB DC-to-DC converter such that the USB DC-to-DC converter receives power from the battery and supplies a regulated voltage to the second electronic device through the USB port while the CPU remains unpowered (not drawing power from the battery).