USB Power Source Enumeration Control for Charging Reliability
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Solution Overview
Problem
Existing USB battery charging technologies fail to properly charge batteries when the controller performing enumeration processing is not activated by the power supplied through USB, limiting charging capabilities.
Innovation Solution
An electronic device with a control unit that allows connection to a first external power source, performs enumeration processing, and includes a charging unit that sets the charge current based on enumeration completion, enabling efficient charging regardless of the USB connection protocol.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the controller is not activated by initial USB power before enumeration processing, then USB battery charging cannot be performed properly according to existing technologies, but the invention enables the controller to be activated and enumeration processing to be completed
Solution Approach 1:
The power source is configured to output predetermined power (exceeding USB protocol limits) to the control unit before enumeration processing is completed. This preliminary power supply enables the control unit to be activated and perform enumeration processing, which would otherwise fail under standard USB power constraints. After enumeration completion, the power source switches to charge current supplied from the external power source, achieving reliable USB battery charging.
2Productivity
If the power source supplies charge current from the first external power source to the charging unit, then charging efficiency is improved, but the control unit requires activation power that exceeds initial USB power limits
Solution Approach 1:
The power source temporarily supplies predetermined activation power to the control unit before enumeration processing. This preliminary power supply phase enables the control unit to become operational and complete enumeration. Once enumeration is complete, the system transitions to efficient charging mode where charge current from the external power source is supplied to the charging unit, achieving both activation and efficient charging.
Solution Approach 2:
The power source dynamically adjusts its output based on the operational state of the control unit. During the pre-enumeration phase, it outputs predetermined power for activation. During enumeration processing, it continues supplying predetermined power. After enumeration completion, it switches to supplying charge current from the external power source. This dynamic power adjustment enables the control unit to overcome initial USB power limitations while maintaining efficient charging operation.
Data Source
AI summary
An electronic device includes a control unit that allows at least a first external power source to be connected thereto and is activated upon receipt of a predetermined power, and a power source connected to the control unit. In an activated state, the control unit performs enumeration processing between the control unit and the first external power source. The power source has charging unit capable of being charged by a charge current supplied from the first external power source, and output unit that outputs the predetermined power from the charging unit to the control unit in response to a connection between the control unit and the first external power source. The charging unit sets the charge current to a current value according to whether the enumeration processing is completed.