USB Interface Pin Status Detection for Charging Policy Selection
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Solution Overview
Problem
Current methods for identifying the type of USB power supply in terminal devices are either costly or limited to detecting standard power adapters, as they require specialized processor chips or additional components, and cannot accurately distinguish between standard and non-standard power adapters without direct support for Battery Charging protocols.
Innovation Solution
A method and terminal design that uses a pull-up resistor to detect the status of USB interface pins, allowing identification of external USB devices without a special processor, by connecting D- and D+ pins to a USB data communication module and controlling charging based on pin status consistency, thereby identifying data transmission devices, standard, and non-standard power adapters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dedicated chips for identifying USB power supply type are used, then identification accuracy is improved, but device cost increases
Solution Approach 1:
The patent replaces expensive dedicated identification chips with inexpensive existing components (pull-up resistor, processor GPIO interface) that are already present in the terminal device. This substitution achieves the same identification function at minimal additional cost, directly resolving the contradiction between identification accuracy and device cost.
Solution Approach 2:
The patent makes the processor's existing GPIO interface serve dual purposes: both general-purpose input/output operations and USB power supply type identification. By reusing existing hardware resources for multiple functions, the patent eliminates the need for dedicated identification chips, thereby reducing device cost while maintaining identification capability.
2Adaptability or versatility
If comparator is added to detect USB power adapter type, then detection capability is improved, but device complexity increases
Solution Approach 1:
The patent enables the existing processor and USB interface components to perform identification functions autonomously through software control of GPIO pins. The system uses its own existing resources (processor, pull-up resistor, USB interface) to detect power adapter types, eliminating the need for external comparator components and reducing overall device complexity.
Solution Approach 2:
The patent introduces a software-based detection mechanism that acts as an intermediary between the USB interface and the processor. This software layer interprets electrical signals from the USB interface through the pull-up resistor configuration, enabling detection capability without adding physical comparator hardware, thus avoiding increased device complexity.
3Measurement precision
If Battery Charging protocol support is required, then identification accuracy is improved, but processor requirements increase
Solution Approach 1:
The patent extracts the identification function from the processor's protocol support capabilities and implements it through a separate detection mechanism using GPIO pins and pull-up resistors. By separating the identification function from the processor's core protocol processing, the patent achieves accurate identification without requiring the processor to support complex Battery Charging protocols, thereby reducing processor requirements.
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 solution reduces the need for high-cost dedicated chips and additional components, enabling accurate identification of USB power supply types across various processor chips, ensuring efficient charging and data communication without requiring Battery Charging protocol support.
Implementation Method 1
a resistance value of the pull-up resistor can ensure that a voltage value obtained by a to-ground pull-down resistor is a logic low level when the pull-up resistor and the to-ground pull-down resistor whose resistance value is approximately 15 KΩ±5% are connected in series to divide a voltage of the power supply
Data Source
AI summary
A method for selecting an internal circuit according to a USB interface status includes: connecting a first pin of a USB interface of a terminal to a power supply through a pull-up resistor, where the first pin is a D− or D+ pin; when detecting that an external USB device is inserted into the USB interface, detecting whether the level status of the first pin is high or low; if the level status is low, connecting the D− and D+ pins to corresponding pins of a USB data communication module of the terminal and controlling charging of the terminal according to a first policy; if the level status is high, determining whether the level statuses of the D− and D+ pins are consistent, and if consistent, controlling charging of the terminal according to a second policy; if inconsistent, controlling charging of the terminal according to a third policy.