Dynamic Current Threshold Power Management Circuit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing USB charging systems in computer systems face limitations in supplying high currents during standby or soft-off states, which can lead to low standby voltage, preventing the system from booting up, and reduce battery durability in notebook computers due to constant power supply requirements for embedded controllers.
Innovation Solution
A power management circuit with a power switch, current/voltage detector, and control unit that sets thresholds for output current and voltage, issuing notification signals to manage power supply operations, ensuring safe and efficient power delivery to external devices and maintaining system bootability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the USB port supplies a large charging current to external devices in standby or soft-off state, then the charging speed is improved, but the standby voltage becomes too low to allow the PC to boot up
Solution Approach 1:
The power management circuit dynamically adjusts the current threshold based on system state. In standby/soft-off states, it uses a first (lower) current threshold to prevent voltage drop that would prevent booting. In working states, it switches to a second (higher) current threshold to enable faster charging. This dynamic adaptation resolves the contradiction between charging speed and system bootability.
Solution Approach 2:
The invention changes the parameter of current threshold based on system operating state. By detecting whether the system is in standby, soft-off, or working state, the circuit adjusts the current limit parameter accordingly. This parameter change allows the system to maintain bootability in low-power states while enabling high-speed charging in working states.
2Reliability
If the embedded controller requires constant power supply to determine battery adequacy, then the system can determine boot capability, but the battery durability is reduced
Solution Approach 1:
The embedded controller performs periodic detection of battery voltage rather than continuous monitoring. The power management circuit enables the EC to detect battery status at specific intervals or under specific conditions (such as when USB charging is detected), rather than maintaining constant power supply. This periodic action reduces unnecessary power consumption while maintaining the ability to determine boot capability.
Solution Approach 2:
The power management circuit incorporates automatic detection of USB device connection and charging status, eliminating the need for continuous EC intervention. The circuit autonomously monitors USB port status and adjusts power delivery accordingly, reducing the burden on the EC and minimizing battery drain while maintaining system awareness of charging state.
Data Source
AI summary
A power management circuit is provided. The power management circuit includes a power switch, a current/voltage detector, a current setting unit, and a control unit. The power switch is coupled to a power supply of the computer system. When the power switch is turned on, it supplies an output current and an output voltage of the power supply to an external device. The current/voltage detector detects the magnitudes of the output current and the output voltage. The current setting unit sets a plurality of current thresholds. When the computer system is in a power-saving state and when the output current is greater than a first current threshold and smaller than a second current threshold or the output voltage is smaller than a first voltage threshold and larger than a second voltage threshold, the control unit issues a notification signal to execute a predetermined operation on the power supply.