Charger Power Source Detection Using Single Data Line
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Solution Overview
Problem
Conventional USB chargers require multiple pins and complex data analysis to distinguish between USB host and AC adapter power sources, leading to increased cost and IC package size due to high pin count and complicated data analysis.
Innovation Solution
A charger with a detection pin, voltage divider, and comparator that identifies the power source by comparing a divided power voltage with predetermined reference voltages on a single data line, reducing the need for multiple pins and simplifying the detection process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two data lines are used to identify power source type, then power source detection accuracy is improved, but IC package pin count and device complexity increase
Solution Approach 1:
The single data line in the USB interface is made to serve dual purposes: both data communication and power source type detection. The charger detects power source type by analyzing voltage levels or data patterns on this single data line, eliminating the need for dedicated detection pins while maintaining detection accuracy.
Solution Approach 2:
Instead of using separate physical pins for detection, the invention uses electrical signal copying on the existing data line. The voltage divider circuit copies and scales the power voltage to detectable levels on the data line, allowing the same line to carry both data and detection functions.
2Measurement precision
If two data lines are used for power source identification, then detection capability is improved, but system cost increases
Solution Approach 1:
The existing data line is made multi-functional to perform both data communication and power source detection, eliminating the need for additional detection circuits and reducing overall system cost while maintaining detection capability.
Solution Approach 2:
The power source detection function is merged with the existing data line communication function. The voltage divider and comparator circuits are integrated into the charger's existing architecture, combining multiple functions into a unified detection mechanism that reduces component count and cost.
3Measurement precision
If multiple pins are used in the charger, then power source detection accuracy is improved, but IC package size increases
Solution Approach 1:
The detection function is extracted from dedicated pins and implemented through signal processing on the existing data line. The voltage divider and comparator circuits process signals electrically rather than requiring separate physical detection pins, reducing the IC package pin count and overall size.
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
Enables autonomous power source detection and USB client speed recognition using a single data line, reducing the IC package pin count, costs, and enhancing efficiency while allowing for controlled charging currents based on the detected power source.
Implementation Method 1
The voltage divider divides a power voltage provided by the power source and provides a detection voltage at the detection pin
Implementation Method 2
The comparator compares the detection voltage with a predetermined reference voltage and identifies a type of the power source according to the comparing
Data Source
AI summary
A charger includes a detection pin, a voltage divider, and a comparator. The detection pin can couple the charger to a power source via a first data line. The voltage divider and the comparator are coupled to the detection pin. The voltage divider divides a power voltage provided by the power source and provides a detection voltage at the detection pin. The comparator compares the detection voltage with a predetermined reference voltage and identifies a type of the power source according to the comparing.