USB Charger Detection Circuit for Port Type Identification
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Solution Overview
Problem
Many USB charging ports, both compliant and non-compliant with the USB Battery Charging 1.2 specification, are incorrectly detected by electronic devices, leading to decreased charging efficiency or failure, as they are unable to accurately differentiate between standard and dedicated charging ports.
Innovation Solution
The electronic device employs a charger detector that applies a current source to a data line of a USB plug while disabling any pull-down resistor on the other data line, determining whether the data line remains at a HIGH or LOW voltage state to identify the port as either a dedicated charging port or a downstream port, and for proprietary ports, applies a current source to a data plus line with an enabled pull-down resistor on the data minus line to determine if it remains at a HIGH state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the BC 1.2 spec charger detection algorithm is used, then compliant USB charging ports can be detected, but non-compliant charging ports are incorrectly detected leading to charging failures
Solution Approach 1:
The patent implements a dynamic detection algorithm that adapts its behavior based on the charging port type. The system performs an initial detection using BC 1.2 spec, then dynamically switches to an alternative detection method when non-compliance is suspected, allowing it to handle both compliant and non-compliant ports effectively
Solution Approach 2:
The patent changes the detection parameters by applying different current sources and measuring different voltage states. Instead of relying solely on the BC 1.2 spec parameters, it uses alternative current applications and voltage threshold checks to identify non-compliant ports, thereby expanding compatibility while maintaining accuracy
2Measurement precision
If charger detection is performed using standard algorithms, then detection speed is maintained, but detection accuracy decreases for non-compliant ports
Solution Approach 1:
The patent performs preliminary detection actions by first attempting BC 1.2 spec detection, then quickly assessing whether the port is compliant based on initial measurements. This preliminary assessment allows the system to prepare the appropriate detection method in advance, minimizing detection time while ensuring accuracy for both compliant and non-compliant ports
Solution Approach 2:
The patent implements a streamlined detection process that skips unnecessary steps when dealing with non-compliant ports. Once non-compliance is detected, the system rushes through to the alternative detection method without performing redundant BC 1.2 spec verification steps, thereby reducing overall detection time while maintaining precision
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 method allows for accurate detection of USB charging ports, ensuring proper charging current is applied, preventing increased charge times or charging failures associated with misidentification of port types.
Implementation Method 1
The charger detector may determine whether the data line has gone to a LOW voltage state or remained at a HIGH voltage state after a predetermined period of time
Data Source
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AI summary
Electronic devices are adapted to facilitate detection of a type of USB charger to which an electronic device is connected. According to one example, an electronic device can apply a current source to a data line of a USB plug coupled to a USB port. A determination can be made whether the data line has gone to a LOW state or remained at a HIGH state after a predetermined period of time. If the data line has gone to a LOW state, the USB port may be identified as a downstream port, such as a standard downstream port (SDP) or a charging downstream port (CDP). If the data line has remained at the HIGH state, the USB port may be identified as a dedicated charging port (DCP), no matter if it is compliant or non-compliant with the BC 1.2 spec. Other aspects, embodiments, and features are also included.