Dynamic Current Limit Protection for USB Power Supply Overload
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Solution Overview
Problem
Conventional current limit protection apparatuses in computer systems are limited to a single current threshold value, leading to power supply overload during sleeping mode, which prevents the system from recovering to a normal mode due to non-compliant USB peripheral devices consuming excessive power.
Innovation Solution
A current limit protection apparatus with multiple current threshold values that can be adjusted based on the computer system's energy-saving modes, using a MOS transistor, current detecting unit, and current limit circuit to select and enforce appropriate current limits via an indicating signal, ensuring proper power management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a single current threshold value (500mA) is used in normal mode, then USB peripheral devices can operate with sufficient power, but power supply overload occurs during sleeping mode when peripheral devices consume excessive current
Solution Approach 1:
The patent implements dynamic current threshold adjustment by switching between a first current threshold (500mA) for normal mode and a second current threshold (2.5mA) for sleeping mode. The control unit receives mode indication signals and dynamically selects the appropriate threshold, allowing the system to adapt current limits to operational requirements and prevent power supply overload during sleep mode.
Solution Approach 2:
The patent changes the current threshold parameter based on operational mode. By modifying the current threshold from 500mA in normal mode to 2.5mA in sleeping mode, the system optimizes power consumption and prevents overload conditions during energy-saving operations while maintaining adequate power supply during full operation.
2Reliability
If the current threshold is set low to prevent power supply overload during sleeping mode, then power supply stability is maintained, but USB peripheral devices cannot receive sufficient current in normal mode
Solution Approach 1:
The system dynamically adjusts the current threshold based on operational mode signals. During normal mode, the higher threshold (500mA) allows sufficient current for peripheral operation, while during sleeping mode, the lower threshold (2.5mA) prevents power supply overload, thus maintaining reliability.
Solution Approach 2:
The current threshold parameter is changed according to the operational mode. The control unit switches between two parameter values (500mA and 2.5mA) based on the mode indication signal, ensuring appropriate current limits are applied for each operational state.
3Device complexity
If only one current threshold value is used, then the device structure is simple, but the system cannot adapt to different operational modes (normal and sleeping)
Solution Approach 1:
The current limit protection device is enhanced with multi-functionality by incorporating mode detection and dynamic threshold selection capabilities. The control unit not only limits current but also adapts to different operational modes (normal and sleeping), making the device versatile across multiple operating conditions without requiring separate protection circuits for each mode.
Solution Approach 2:
The system transitions from a static single-threshold design to a dynamic multi-threshold design. The control unit dynamically selects between first and second current thresholds based on operational mode signals, enabling the device to adapt to different operational requirements while maintaining a unified circuit structure.
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
Prevents power supply overload during sleeping mode by dynamically adjusting current limits, allowing the computer system to smoothly recover from sleep mode by limiting current to USB peripherals according to their operational modes.
Implementation Method 1
a gate of the MOS transistor is used for receiving a gate driving signal to determine a conducting current of the MOS transistor
Implementation Method 2
The current detecting unit is used for detecting the conducting current of the MOS transistor, so as to generate a detecting result
Data Source
AI summary
A current limit protection apparatus and a method for current limit protection are provided. The current limit protection apparatus includes a MOS transistor, a current detecting unit, and a current limit circuit. Two source/drain of the MOS transistor are used for receiving a first-voltage and outputting a second-voltage respectively. A gate of the MOS transistor is used for receiving a gate driving signal to determine a conducting current of the MOS transistor. The current detecting unit is used for detecting the conducting current, so as to generate a detecting result. The current limit circuit has a plurality of current threshold values. The current limit circuit selects one of the current threshold values according to an indicating signal and generates the gate driving signal according to a difference between the selected current threshold value and the detecting result.