USB Combo ID Detection Module for Fast Accessory Identification
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Solution Overview
Problem
Traditional USB ID detection methods are limited in determining resistance values within a given time period, typically taking around 200 ms to identify 32 unique resistance values, which restricts the number of accessories that can be identified quickly and accurately.
Innovation Solution
The proposed ID detection systems and methods enable the determination of multiple unique ID resistances from a single or multiple accessories in less than 25 ms, using a combo ID detection approach that begins detection at a lower resistance value, tailors RC charge times for each digital-to-analog-converter value, and employs a halt counter to maintain detection within time constraints, allowing for a larger number of resistance values to be identified without sacrificing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional USB ID detection methods are used, then detection accuracy is maintained, but the detection time is too long (around 200 ms)
Solution Approach 1:
The system performs preliminary actions by starting the detection process at a lower resistance value before the traditional highest value. This preliminary approach to detection sequencing allows the system to identify accessories faster by checking resistance values in an optimized order that reduces overall detection time while maintaining accuracy
Solution Approach 2:
The patent changes the detection parameter sequence by starting at lower resistance values rather than higher ones. This parameter change in the detection strategy enables faster identification of common accessories while maintaining the ability to detect all resistance values, thereby reducing detection time from 200 ms to under 25 ms
2Productivity
If more resistance values are checked in a given time period, then the number of identifiable accessories increases, but the detection time for each value decreases
Solution Approach 1:
By performing preliminary detection at lower resistance values first, the system can quickly identify common accessories and stop the detection process early, thereby increasing productivity without compromising precision for the detected values
3Loss of time
If detection starts at a lower resistance value, then detection time is reduced, but the traditional detection sequence is disrupted
Solution Approach 1:
The patent applies inversion by reversing the traditional detection sequence - instead of starting at the highest resistance value and working downward, the system starts at lower resistance values and progresses upward. This inverted approach reduces detection time while the complexity is managed through systematic sequencing and state machine control
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 allows for the identification of a greater number of unique ID resistance values in a shorter time frame, supporting up to 23 ID resistance values from 2 k ohms to 200 k ohms in 25 ms or less, while maintaining accuracy and flexibility to accommodate additional values, thereby enhancing USB accessory detection efficiency.
Implementation Method 1
Traditional USB identification (ID) detection can determine an ID resistance in approximately 200 ms, with 1 nF of load capacitance
Implementation Method 2
the type of accessory connected to the USB switch can be identified by detecting a resistance of the accessory
Data Source
AI summary
This document discusses, among other things, an identification (ID) detection module configured to identify a first ID code in a first detect period within a first attach period and to identify a second ID code in a second detect period within the first attach period.