USB-C Power Rail Control During Desktop Low-Power States
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Solution Overview
Problem
Computing devices face challenges in powering external USB devices during low power states, as the reduced power output from the standby power rails is often insufficient for charging, leading to inefficient power management and potential disruptions in device functionality.
Innovation Solution
Implementing a dynamic control mechanism for the ATX main rails to maintain power to USB ports during low power states by determining the power consumption of connected devices and switching between main and standby power rails based on allocated budgets, ensuring continuous charging and wake support for devices with higher standby power requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the computer transitions to a sleep state with reduced power output, then power consumption is reduced, but the power output becomes insufficient to power external USB devices
Solution Approach 1:
The system dynamically switches between sleep state and modified low power state based on USB device power needs. The EC monitors USB device presence and power requirements, then dynamically adjusts the power supply state accordingly, allowing the system to optimize power consumption while ensuring sufficient power delivery when external devices are connected
Solution Approach 2:
The embedded controller continuously monitors the power consumption of connected USB devices and provides feedback to the power supply management system. This feedback mechanism enables the system to detect when USB devices require more power than the standby rail can provide, triggering a transition to the modified low power state with main power rails activated
2Power
If the main power rails are kept on during low power state, then sufficient power is provided to USB ports, but power consumption increases
Solution Approach 1:
The system employs dynamic state transitions between sleep mode and modified low power state based on real-time USB device monitoring. When USB devices are detected with power requirements exceeding standby capabilities, the system dynamically activates main power rails; when no such devices are present, it returns to sleep mode, optimizing the balance between power output and consumption
Solution Approach 2:
The embedded controller performs preliminary monitoring of USB device power requirements before transitioning power supply states. By detecting USB device presence and power needs in advance, the system can proactively activate main power rails when needed, preventing power insufficiency issues before they occur
Data Source
AI summary
Embodiments herein relate to a computer which operates in a normal power mode, a full low power mode and a modified low power mode. A power supply unit (PSU) includes main power rails and a standby power rail. An intelligent decision is made as to when to turn on and off the main power rails based on the needs of connected devices such as USB Type-C devices. Power Delivery controllers communicate with the USB devices to determine their power consumption needs, and the total power consumption is aggregated at an embedded controller. If the total exceeds an available power budget, the PSU is controlled to allow for a modified low power mode in which full power is maintained at the main power rails while non-essential internal components are turned off.