Tapped Winding Flyback Converter for USB-C Voltage Adaptation
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Solution Overview
Problem
Existing flyback converter designs face challenges in providing multiple output voltage levels efficiently due to complex circuit designs and inability to adapt to varying device requirements, particularly with the increasing need for a wide range of output voltages in USB-C standards.
Innovation Solution
The use of a transformer with a tapped secondary winding and one or more switching devices to control the duty cycle and perform synchronous rectification, allowing for the production of multiple output voltages with a minimally complex circuit design by adjusting the turn-ratio and operating parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single power converter design is used, then the circuit design is simple, but it cannot satisfy different voltage requirements of multiple devices
Solution Approach 1:
The patent implements dynamic adaptability by enabling the power converter to switch between different operating modes (full-bridge and half-bridge) and adjust the number of active secondary windings based on the connected device's power requirements. This dynamic configuration allows a single converter design to adapt to multiple voltage and power level requirements without requiring multiple dedicated designs
Solution Approach 2:
The patent creates a universal power converter that can serve multiple functions by incorporating multiple secondary windings that can be selectively activated. The converter can simultaneously support different voltage outputs (e.g., 20V, 12V, 5V) and power levels by engaging different combinations of windings, making it universally applicable to various USB devices with different power needs
2Adaptability or versatility
If a tapped winding configuration is used to produce multiple output voltages, then the voltage adaptability is improved, but the circuit design becomes overly complex
Solution Approach 1:
The patent segments the secondary winding into multiple independent, identically-rated windings instead of using a single tapped winding. Each winding can be independently activated or deactivated, providing multiple output voltage levels while maintaining simpler individual winding designs. This segmentation approach avoids the complexity of tapped windings while achieving the same voltage adaptability
Solution Approach 2:
The patent merges multiple identical secondary windings in parallel or series configurations to achieve different output voltages. By combining simple, identical winding units rather than using a complex single tapped winding, the design achieves voltage versatility while keeping each individual winding component simple and standardized
3Adaptability or versatility
If the duty cycle range is widened to support multiple output voltages, then the voltage adaptability is improved, but the control precision and efficiency deteriorate
Solution Approach 1:
The patent changes the fundamental operating parameters by switching between full-bridge and half-bridge modes, and by activating different numbers of secondary windings. These parameter changes allow the system to maintain a narrow, optimized duty cycle range (40-60%) in each mode while achieving wide overall voltage adaptability. Each operating mode has its own optimized parameter set, avoiding the need for a single wide-duty-cycle range that would compromise precision
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
This approach enables flyback converters to efficiently support a wide range of output voltages, simplifying the design and optimizing performance for each voltage level, while maintaining a narrow duty cycle range, thus addressing the limitations of prior art power adapters.
Implementation Method 1
A transformer in an AC to DC power converter may have primary and secondary windings. A pulse width modulation (PWM) circuit on the primary side of a transformer may generate pulses of current that pass through the primary winding of the transformer.
Implementation Method 2
A pulse width modulation (PWM) circuit on the primary side of a transformer may generate pulses of current that pass through the primary winding of the transformer
Implementation Method 3
Some AC to DC power converter circuits use synchronous rectifier (SR) output stages. SR output stages may include a metal-oxide-semiconductor field-effect transistor (MOSFET). The MOSFET is driven so as to rectify the output waveform from the transformer in the same way that the diode is used in other power converter designs, while avoiding high diode voltage drops when conducting current
Data Source
AI summary
This disclosure relates to power converters capable of providing multiple output voltage levels. With respect to USB-C adapter design, the converter's output may need to be changed between different voltage levels, e.g., a low voltage (such as 5V, 10V), an intermediate voltage (such as 12V, 20V), or a high voltage (such as 20V, 40V)—based on the charging device's request. By using a tapped-winding transformer, the turns-ratio of a flyback transformer may be intelligently selected for high output voltage ranges, thus enabling the duty cycle to be kept the same for the low and intermediate voltage output levels. The flyback converter would then only need to accommodate the intermediate and high output voltages. For high output voltages, a switch may be activated to put the two windings of the transformer in series; for lower output voltages, the switch may be turned off, such that only one winding is used.