USB Hub Controller Power Limit Management for Startup
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Solution Overview
Problem
USB-connected electronic devices with high power consumption, such as digital cameras, face challenges in starting up and switching USB device classes due to power limitations from USB bus power, which are insufficient for initial configurations and class switching operations when battery charge is low.
Innovation Solution
A control device with a first controller that manages power requests and sets a higher power supply limit from an external apparatus, and a second controller that generates and supplies power to a core chip, enabling increased power supply from 5V×100 mA to 5V×500 mA during configuration and class switching, ensuring sufficient power for startup and operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If USB bus power is used for starting up an electronic apparatus with no remaining battery charge, then the apparatus can be powered externally, but the power is limited to 5V×100 mA before configuration and cannot support startup
Solution Approach 1:
The patent applies preliminary action by performing the USB configuration process before attempting startup with limited power. The system first establishes the USB connection and completes enumeration/configuration while the battery still has charge, thereby securing a higher power allocation (5V×500 mA) for subsequent startup operations. This preliminary configuration action resolves the contradiction by ensuring the power limit is raised before the high-power startup is attempted.
2Adaptability or versatility
If USB device class switching is performed during operation, then the apparatus can switch between charging mode, playing mode, and shooting mode, but the USB connection is electrically disconnected and reconnected causing power limitation to drop to 5V×100 mA
Solution Approach 1:
The patent applies dynamics by implementing a dynamic power management strategy that adapts to USB connection state changes. When USB device class switching occurs and the connection is temporarily disconnected, the system dynamically detects the reconnection and re-establishes the configuration state, thereby dynamically restoring the higher power limit (5V×500 mA). This dynamic response resolves the contradiction by maintaining adaptability while preventing unnecessary power limit reductions.
3Device complexity
If a large-scale core chip with USB connecting function is used, then the apparatus integrates multiple functions in one chip, but the power consumption is relatively high making USB bus power insufficient
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the power supply parameters based on the operational state and USB configuration status. The system changes the power limit parameter from 5V×100 mA (pre-configuration) to 5V×500 mA (post-configuration) to match the higher power consumption requirements of the integrated core chip. This parameter adjustment resolves the contradiction by aligning power supply capacity with the actual power consumption needs of the high-integration chip.
Data Source
AI summary
When an electronic apparatus including a core chip and a hub controller chip is connected to an apparatus on the host side, a USB hub controller in the hub controller chip executes a process on a configuration between the USB hub controller and the apparatus on the host side and sets a limit value of power to be supplied, from a first limit value to a second limit value higher than the first limit value, and a VBUS current controller in the hub controller chip supplies the core chip with a power supply voltage generated based on a supplied power, which allows to maintain a configuration state between the apparatus on the host side and the USB hub controller at a time of starting up or at a time of class switching of the core chip and supply the core chip with the sufficient power.