Multiport USB Power Adaptor with Flyback-Buck Topology
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Solution Overview
Problem
Current multiport USB power adaptors are expensive and not scalable beyond two ports, while those using the flyback-buck topology suffer from lower power efficiency than USB Power Delivery specifications.
Innovation Solution
A multiport USB power adaptor design incorporating a flyback-converter, multiple buck-circuits, and bypass-circuits, along with a USB controller that operates in variable-buck-input-mode or buck-bypass-mode to efficiently manage output voltages across multiple USB ports, optimizing power delivery and scalability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a dual-flyback-converter topology is used, then multiple USB ports can be independently operated to provide the same or different secondary voltages, but the adaptor becomes expensive and not readily scalable to more than two ports
Solution Approach 1:
The power adaptor is divided into modular components: a single flyback-converter core and multiple independent buck-converters. Each buck-converter can be independently enabled or disabled, allowing the system to scale from 2 to 4+ ports by simply adding more buck-converter modules rather than redesigning the entire power conversion architecture.
Solution Approach 2:
The single flyback-converter serves as a universal power source that can supply power to multiple USB ports through the shared transformer. The transformer's multiple secondary windings can serve different ports, and the system can dynamically allocate power based on which ports are active, making the design adaptable to varying port configurations.
2Loss of energy
If a flyback-buck-controller topology is used, then multiple USB ports can be independently operated to provide the same or different secondary voltages, but the power efficiency is lower than specified in USB Power delivery specifications
Solution Approach 1:
The system dynamically switches between two operational modes based on load conditions: buck-mode for high efficiency when voltage step-down is needed, and direct-mode when the flyback-converter output voltage matches the required USB port voltage. This dynamic adaptation minimizes energy losses by selecting the most efficient path for each operating condition.
Solution Approach 2:
The controller changes operational parameters (voltage levels, switching frequencies, mode of operation) based on the power delivery requirements of connected devices. By adjusting these parameters in real-time, the system maintains optimal efficiency across different USB Power Delivery voltage levels (5V, 9V, 12V, 15V, 20V) while meeting specification requirements.
3Loss of energy
If bypass-circuits are added to enable buck-bypass-mode, then power efficiency is improved by eliminating buck-converters for certain ports, but the device complexity increases
Solution Approach 1:
The bypass-circuit is extracted as a separate, independent component that can be selectively activated. When a USB port requires the same voltage as the flyback-converter output, the bypass-circuit is engaged to directly connect the port to the flyback output, effectively removing the buck-converter from the power path for that port. This extraction allows the system to minimize complexity by only activating bypass-circuits when needed.
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
The solution provides an inexpensive, power-efficient topology that is readily scalable, offering improved efficiency and adaptability in managing output voltages across multiple USB ports, enhancing overall power delivery performance.
Implementation Method 1
A flyback-converter generally includes a controller and a transformer, and is configured to receive an input voltage from a power source coupled to a primary side of the transformer and to provide a second voltage on a secondary side coupled to an output port or socket
Implementation Method 2
A multiport USB power adaptor using a flyback-buck-controller topology includes a flyback-converter coupled to two or more independent buck-controllers, each coupled to a separate USB port or socket
Data Source
AI summary
A multiport USB-PD adaptor including a flyback-converter, a USB controller including a USB-PD subsystem and buck-controller, and multiple buck and bypass-circuits, and methods for operating the same are provided. Generally, the adaptor is operated in a buck-bypass-mode, in which at least one buck-circuit is bypassed and the flyback-converter is operated to generate an input voltage (VIN) to the buck-circuits equal to a requested output voltage (VOUT_C), which is then coupled directly to the associated port. Buck-circuits coupled to other active ports can also be bypassed if the requested VOUT_Cs are the same, or the buck-circuits operated to provide another VOUT_C. If a bypass-circuit unavailable, the adaptor is operated in a variable-buck-input-mode by determining a highest VOUT_C requested on any port and setting VIN to a sum of the highest VOUT_C and an offset voltage. Buck-circuits coupled to active ports are then operated to provide the requested output voltages.