Adaptive Resonant Timing in Half-Bridge Flyback Voltage Conversion
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Solution Overview
Problem
In asymmetrical half-bridge flyback conversion circuits, the change in parasitic capacitors due to varying output voltage affects resonance parameters, leading to inefficient control of power transistors and reduced conversion efficiency.
Innovation Solution
A control circuit monitors output voltage changes and adaptively detects and updates the resonant period, adjusting drive signals based on the updated resonant period to improve efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the resonant period is fixed based on initial parasitic capacitor values, then the control circuit is simple, but conversion efficiency deteriorates when output voltage changes
Solution Approach 1:
The patent implements dynamic detection and updating of the resonant period based on real-time output voltage changes. The control circuit continuously monitors the resonant waveform and adapts the resonant period parameter, transforming the static control approach into a dynamic one that maintains optimal conversion efficiency across varying output conditions.
Solution Approach 2:
The patent employs feedback mechanisms where the control circuit detects output voltage changes and uses this information to adjust the resonant period. By monitoring the resonant waveform and feeding back the detected resonant period to the control logic, the system automatically optimizes transistor switching timing, resolving the contradiction between simplicity and efficiency.
2Loss of energy
If the resonant period is adaptively detected and updated, then conversion efficiency is improved, but device complexity increases
Solution Approach 1:
The patent enables the control circuit to self-adjust the resonant period by autonomously detecting output voltage changes and calculating the updated resonant period from the monitored resonant waveform. This self-service capability allows the system to maintain high conversion efficiency without requiring external intervention or complex manual calibration.
Solution Approach 2:
The patent changes the resonant period parameter dynamically based on output voltage conditions. By detecting voltage changes and corresponding resonant waveform variations, the system adjusts the resonant period parameter in real-time, achieving improved conversion efficiency across wide output voltage ranges while keeping the adjustment mechanism integrated within the existing control circuit.
3Device complexity
If parasitic capacitor values are assumed constant, then the control approach is simple, but resonance parameters become inaccurate when output voltage varies
Solution Approach 1:
The patent performs preliminary detection of output voltage changes before adjusting the resonant period. By monitoring voltage variations in advance and proactively updating the resonant period parameter, the system ensures accurate resonance parameters are maintained throughout operation, preventing performance degradation before it occurs.
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
Enhances conversion efficiency by adaptively adjusting control signals in response to output voltage variations, optimizing performance across a wide range of output voltages.
Implementation Method 1
Parasitic capacitors, resonant capacitors, and resonant inductors of the main power transistor and the auxiliary power transistor, and an excitation inductor on a primary side of the transformer resonate together
Implementation Method 2
a primary winding of the transformer is connected in parallel with the first switching transistor or the second switching transistor by using the resonant capacitor and the resonant inductor
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
This application provides a voltage conversion apparatus, a control method, and a power supply device. The voltage conversion apparatus includes a control circuit. The control circuit is configured to: obtain a first sampling voltage and a second sampling voltage; detect a resonant period based on the second sampling voltage when it is determined, based on the first sampling voltage, that a voltage range of an output voltage of the voltage conversion apparatus changes and a voltage threshold is exceeded; and output a drive signal based on the detected resonant period. The drive signal is used to control turn-on and turn-off of a first switching transistor and a second switching transistor. In this application, a change of a direct current output voltage is monitored, the resonant period of the voltage conversion apparatus is adaptively detected and updated, and then the drive signal is adjusted based on the updated resonant period, so that conversion efficiency of the voltage conversion apparatus is improved under a wide-range output.