Bus-Powered Peripheral Charging Circuit for ACPI Wake Control
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Solution Overview
Problem
Existing information handling systems face challenges in efficiently waking from deep sleep mode to charge battery-powered portable devices via bus-powered external I/O ports without draining the host system's battery.
Innovation Solution
A circuit comprising a signal converter and a ground loop detector is used between the input port and the controller to sense peripheral device coupling, restrict unnecessary state changes, and maintain the ACPI state, allowing controlled waking from G3 to S5 for charging while preventing excessive power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the host system wakes from G3 deep sleep mode to charge peripheral device battery, then charging function is enabled, but battery power is significantly drained
Solution Approach 1:
The patent introduces an intermediary circuit between the peripheral device and the host system that can detect device coupling and autonomously control the charging process. This intermediary manages the power flow and state transitions without requiring the host system to fully wake, thereby enabling charging functionality while minimizing battery power consumption.
Solution Approach 2:
The system performs preliminary detection of device coupling through the intermediary circuit before the host system wakes from G3 mode. This preliminary action allows the system to prepare charging conditions in advance, ensuring that the host only transitions to S5 state when necessary and appropriate, thus reducing unnecessary power consumption.
2Speed
If the controller changes ACPI state multiple times for device coupling, then charging responsiveness is improved, but power consumption increases and hysteresis behavior occurs
Solution Approach 1:
The patent implements a feedback mechanism where the intermediary circuit continuously monitors device coupling status and provides this information to the controller. This feedback allows the controller to make informed decisions about state transitions, changing ACPI state only when device coupling is confirmed and charging is actually needed, thereby improving responsiveness while avoiding unnecessary state changes that waste energy and cause hysteresis behavior.
Data Source
AI summary
Optimized bus powered peripheral battery charging includes a circuit to initiate a change in an advanced configuration and power interface (ACPI) state in a controller allowing charging of a peripheral device battery, the circuit including a signal converter coupled between an input port and the controller to sense when a the peripheral device battery is coupled to an input port and to restrict the controller from changing ACPI state multiple times for a given peripheral device battery coupling; and a ground loop detector coupled in parallel to the signal converter between the input port and the controller to allow the controller to know that the peripheral device battery has maintained being coupled to the input port.