Pull-Down Circuitry for USB Type-C Power Request
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Solution Overview
Problem
Devices with Dual-Role Ports, such as those using USB-Type C connectors, face challenges in requesting power from a power provider when they have no energy or a dead battery, as they need to pull down the Configuration Channel voltage without any internal power to initiate charging from the VBUS line, which existing technologies struggle to efficiently manage.
Innovation Solution
Incorporating a pull-down circuit within the device, connected via the Configuration Channel line over a USB-Type C cable to a power provider, utilizing components like N-channel FETs, p-channel FETs, or diodes to reduce the voltage on the Configuration Channel line, signaling the power provider to supply power through the VBUS line, and releasing control once the device is powered or the battery is charged.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a device with Dual-Role Port needs to request power from a power provider when it has no energy or dead battery, then it must pull down the Configuration Channel voltage to initiate charging, but it lacks internal power to operate the pull-down circuit effectively
Solution Approach 1:
The pull-down circuit is designed to activate automatically when the device detects low or no battery energy, performing the voltage pulling action before the device has sufficient power to operate normally. This preliminary action initiates the power request sequence using minimal residual energy.
Solution Approach 2:
The Configuration Channel voltage serves as an intermediary signal between the power consumer device and the power provider. By manipulating this intermediate voltage level, the device can communicate its power needs without requiring full operational power.
2Reliability
If the pull-down circuit continuously pulls down the Configuration Channel voltage to ensure power request, then power negotiation is maintained, but energy is consumed continuously even when not needed
Solution Approach 1:
The pull-down circuit incorporates dynamic control mechanisms that adjust its operation based on real-time battery status monitoring. When battery charge reaches sufficient levels, the circuit automatically reduces or stops the pull-down action, transitioning from a static continuous operation to a dynamic conditional operation.
Solution Approach 2:
The system implements feedback control where the battery management circuit continuously monitors battery charge levels and provides feedback signals to the pull-down circuit. This feedback loop enables the pull-down circuit to modulate its activity based on current energy status, ensuring power requests are maintained only when necessary.
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
Enables effective power negotiation and charging by allowing devices to request power via a wired interface, ensuring that devices can initiate charging even without internal power, and managing power consumption efficiently by dynamically controlling the pull-down circuit based on battery status.
Implementation Method 1
an N-channel FET, having its gate coupled through a resistor to the configuration channel line of the cable, its source connected to ground potential, and its drain connected to the configuration channel line of the cable, the N-channel FET being configured to become more conductive, reducing voltage on the configuration channel line of the cable
Implementation Method 2
a p-channel FET, having its gate coupled through a resistor to ground potential, its drain connected to ground potential, and its source connected to the configuration channel line of the cable, the p-channel FET being configured to conduct through its source-drain path, thereby reducing voltage on the configuration channel line of the cable
Implementation Method 3
a diode, with its cathode coupled through a resistor to ground potential and its anode connected to the configuration channel line of the cable, the diode being configured to conduct, thereby reducing voltage on the configuration channel line of the cable
Data Source
AI summary
Apparatus embodiments of the invention are disclosed for requesting power via a wired interface. In example embodiments, a pull-down circuit in the apparatus acting as a power consumer when there is no energy in the apparatus, is connected via a configuration line over a cable to a power provider device. The apparatus may be in a power down mode, it may have an empty battery, or it may have no battery. The pull-down circuit is configured to use energy from the configuration line to pull down a voltage on the configuration line, to signal the power provider device to provide power over another line of the cable to the apparatus.