USB Attachment Detection Using Low Frequency Clock
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Solution Overview
Problem
The existing USB attachment detection methods, such as ADP probing, require continuous high frequency clock usage for periodic attachment state checks, leading to increased power consumption and reduced autonomy in devices like mobile phones and portable computers.
Innovation Solution
Implementing a method that uses a low frequency clock to periodically detect changes in the USB attachment state, allowing the device to remain in a sleep state until a change is detected, and then activating the high frequency clock to handle the event, thereby reducing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ADP probing is executed periodically using high frequency clock, then attachment state detection is reliable, but power consumption increases
Solution Approach 1:
The patent implements periodic attachment detection using a low frequency clock instead of continuous high frequency clock operation. The detection is triggered at intervals defined by the low frequency clock, allowing the system to maintain detection capability while significantly reducing power consumption during idle periods.
Solution Approach 2:
The patent changes the operational parameter of the clock frequency from high frequency to low frequency for the attachment detection function. This parameter change allows the system to perform the same detection task with much lower energy consumption, resolving the contradiction between reliable detection and power usage.
2Speed
If high frequency clock is continuously activated for attachment detection, then detection response is fast, but device autonomy is reduced
Solution Approach 1:
The system uses periodic triggering based on a low frequency clock to activate attachment detection only when needed, rather than maintaining continuous high frequency operation. This allows the device to enter low-power states between detection cycles, extending autonomy while maintaining detection capability.
Solution Approach 2:
The low frequency clock is kept running continuously to prepare for and trigger detection events, allowing the system to quickly activate high frequency clock only when an attachment event is anticipated or detected, rather than maintaining it continuously.
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 approach enables the detection of USB attachment state changes without continuous high frequency clock usage, significantly reducing power consumption and extending the autonomy of portable devices.
Implementation Method 1
the ADP protocol allows for the detection of this event by observing changes in capacitance in the power supply line VBus of the interface 15
Data Source
AI summary
A change is managed in the attachment state between a first device and a second device which are connected via an interface. The first device comprises a high frequency clock. The first device is in a sleep state in which the high frequency clock is deactivated. A detection of a change in the attachment state of the second device is periodically triggered on said interface, on the basis of a low frequency clock. Upon detection of a change in the attachment state, the sleep mode is exited by activating the high frequency clock.