Power Receiver Control Unit Prevents Shutdown During USB Capability Transition
Solution Overview
Problem
In electronic devices that operate as power receiving apparatuses, there is a risk of unexpected shutdown due to power supply from the power supply apparatus falling below the device's power consumption, especially when the power supply capability shifts from higher standards to Default USB, as the determination of power supply capability according to legacy standards takes time and may not be completed before power reduction occurs.
Innovation Solution
An electronic device with a connector having specific terminals (first, second, third, and fourth) that includes a receiving power control unit, a determination unit, and a control unit to restrict power reception from the power supply apparatus via the first terminal when a predetermined transition occurs in the second terminal, and subsequently determines the power supply capability using the third and fourth terminals to ensure power does not exceed the device's capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the power receiving apparatus waits for the determination of power supply capability according to legacy standard, then the power supply capability can be accurately determined, but the determination time increases and power supply may be suppressed before completion
Solution Approach 1:
The power receiving apparatus performs preliminary detection of the CC terminal voltage to predict the power supply capability before completing the full legacy standard determination process. This preliminary action allows the device to prepare appropriate power reception settings in advance, reducing the overall determination time while maintaining accuracy through subsequent verification.
Solution Approach 2:
The system continuously monitors the CC terminal voltage and compares it with predefined thresholds to provide feedback on the power supply capability. This feedback mechanism allows the power receiving apparatus to dynamically adjust its power reception parameters during the determination process, ensuring accurate capability identification while optimizing the determination time.
2Adaptability or versatility
If the power supply capability determination is performed using legacy standard, then compatibility with older devices is maintained, but the determination process is slower compared to USB Type-C standard
Solution Approach 1:
The power receiving apparatus dynamically selects the determination method based on the detected connector type and device capabilities. When a USB Type-C connector is detected, the faster Type-C determination protocol is used; when legacy connectors are detected, the apparatus switches to the legacy standard determination process, optimizing speed while maintaining compatibility.
Solution Approach 2:
The system changes the determination parameters (such as terminal usage and voltage thresholds) based on the detected power supply apparatus type. For USB Type-C connections, the apparatus uses CC terminal voltage thresholds defined in the Type-C standard; for legacy connections, it uses D+ and D- terminal signaling, thereby adapting the determination process to achieve optimal speed for each standard.
3Adaptability or versatility
If power supply capability shifts from 15W or 7.5W to Default USB, then the power supply apparatus can operate in legacy mode, but the power receiving apparatus may experience unexpected shutdown due to insufficient power
Solution Approach 1:
When a power supply capability shift is detected, the power receiving apparatus performs preliminary detection of the new CC terminal voltage to identify the shifted power supply capability before the actual power transition occurs. This preliminary action allows the apparatus to pre-adjust its power reception parameters, ensuring continuous stable operation during the capability transition from high-power mode to Default USB mode.
Solution Approach 2:
The system implements a buffer mechanism by detecting power supply capability shifts in advance and preparing appropriate power reception settings before the transition completes. This cushioning approach prevents power deficiency during the transition period, maintaining operation stability even when shifting from 15W or 7.5W to Default USB power supply capability.
Data Source
AI summary
An electronic device includes a connector that includes a first terminal for receiving power from a power supply apparatus, a second terminal, a third terminal, and a fourth terminal; a receiving power control unit that controls power received from the power supply apparatus via the first terminal; a determination unit that determines a power supply capability of the power supply apparatus by using the second terminal or the third terminal and the fourth terminal; and a control unit that restricts, before the power supply capability of the power supply apparatus is determined by using the third terminal and the fourth terminal, power to be received from the power supply apparatus via the first terminal when a predetermined transition occurs in the second terminal.