USB Camera Power Reduction via Host Controller Suspend
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Solution Overview
Problem
Current USB camera video streaming protocols, such as USB 1.0 and 2.0, result in significant power wastage due to continuous data transmissions between frames, even when no image data is being sent, preventing deep power states in computing devices and increasing energy consumption.
Innovation Solution
Modifying the USB protocol to transmit a non-data no acknowledge (NAK) signal instead of zero-data transmissions, allowing the computing device to enter deeper sleep states and reducing unnecessary data transfer between frames.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If USB protocol transmits data continuously between frames, then data transmission reliability is improved, but power consumption increases
Solution Approach 1:
The patent implements periodic data transmission by suspending USB data transmissions between video frames and resuming them at frame boundaries. The host controller suspends the USB bus during idle periods between frames and resets it at the start of each frame transmission, creating a periodic transmission pattern that eliminates continuous data flow while maintaining frame-synchronized reliability.
2Adaptability or versatility
If USB protocol sends zero-byte data transmissions between frames, then protocol compliance is improved, but processor wake events increase
Solution Approach 1:
The patent extracts and removes the harmful element of zero-byte data transmissions from the USB protocol stream. Instead of sending empty DATA0 packets between frames, the host controller suspends the USB bus entirely during idle periods, eliminating the wake-triggering transmissions while maintaining protocol compliance through proper suspend/resume sequencing at frame boundaries.
3Productivity
If USB host controller maintains continuous data requests, then data transfer efficiency is improved, but system idle current increases
Solution Approach 1:
The host controller implements periodic request transmission by suspending USB data requests during idle periods between frames and resuming them at frame boundaries. This creates a rhythmic pattern of active transmission and idle suspension, eliminating continuous request signaling while maintaining efficient data transfer during active frame transmissions.
4Speed
If USB protocol uses isochronous mode for video streaming, then real-time data transmission is improved, but power waste increases
Solution Approach 1:
The patent dynamically adjusts the USB transmission state based on real-time data availability. The host controller suspends the USB bus during idle periods when no video frame data is being transmitted and resets it at the start of each frame transmission, creating a dynamic transmission pattern that maintains real-time capability during active frames while eliminating power waste during idle periods.
Data Source
AI summary
A method, system, and article provide image processing with power reduction while using universal serial bus cameras.