USB Power Tap Controller Initialization Signal

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Solution Overview

Problem

Electronic devices that tap USB power without considering the USB host port's power management requirements may face issues such as insufficient power, suspension, and potential damage due to inrush current, leading to unreliable operation and damage to the USB host port.

Innovation Solution

A USB-enabled device with a controller that provides a USB initialization signal, allowing it to tap USB power from a remote USB port while complying with the USB standard, ensuring reliable power supply up to 500 mA without installing specific drivers or software, and maintaining power management compliance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If USB power is tapped without proper initialization, then the device can connect to USB host port, but the USB host port may provide insufficient power (limited to 100 mA) or enter suspend mode

Engineering Contradiction:

Improvepower supply reliabilityVSAvoidUSB power availability

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The patent applies preliminary action by performing USB initialization and enumeration procedures before the USB host port can provide full power. The controller executes standard USB protocols during connection to establish proper power allocation, ensuring the port transitions from default 100 mA limitation to full 500 mA power mode before the device begins operation.

Inventive Principle:

Principle #10Preliminary action

2Ease of operation

If USB power is tapped without proper initialization, then the device can connect to USB host port, but the inrush current may exceed current limitation and damage the USB host port

Engineering Contradiction:

Improveconnection simplicityVSAvoidinrush current damage

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by executing USB initialization protocols before full power transfer begins. The controller performs enumeration and power negotiation during the connection phase, establishing current limits and protection mechanisms before the device draws full operating current, thereby preventing inrush current damage to the USB host port.

Inventive Principle:

Principle #10Preliminary action

3Loss of energy

If USB host port suspends the USB bus due to lack of data transactions, then power consumption is reduced to 500 μA, but the electronic device may loose power or be reset

Engineering Contradiction:

ImproveUSB power drawVSAvoiddevice operation continuity

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The patent applies continuity of useful action by maintaining periodic data transactions or power management communication over the USB bus to prevent the host port from entering suspend mode. The controller actively manages the USB connection to ensure continuous power delivery while minimizing power consumption, preventing device reset or power loss.

Inventive Principle:

Principle #20Continuity of useful action

Data Source

PatentUS8065451B2Device for tapping USB power

Publication Date: 2011.11.22 MAXLINEAR INC

AI summary

A device includes a universal serial bus (USB) port comprising a data terminal and a power terminal to receive power from a remote USB port. The device includes a controller coupled to the data terminal of the USB port to provide a USB initialization signal.