Resonant Power Converter Control for High-Side Zero-Voltage Switching
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Solution Overview
Problem
Resonant power conversion circuits generate excessive power loss to achieve zero-voltage switching, particularly under heavy and light load conditions, necessitating optimization for improved efficiency.
Innovation Solution
Adjusting the conduction time of the low-side transistor to control the circulating current, utilizing a control circuit that includes a resonant capacitor, transformer, and voltage-dividing circuits to achieve zero-voltage switching of the high-side transistor while enhancing conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If resonant power conversion circuit uses conventional switching control to achieve zero-voltage switching, then high efficiency is improved, but power loss increases under heavy and light load conditions
Solution Approach 1:
The control circuit performs preliminary action by adjusting the conduction time of the low-side transistor before the high-side transistor switches. This advance adjustment ensures that the circulating current is properly established, enabling zero-voltage switching to be achieved without excessive power loss under varying load conditions
Solution Approach 2:
The invention applies dynamics by making the conduction time of the low-side transistor adjustable rather than fixed. The control circuit dynamically adjusts the conduction time based on load conditions, allowing the circuit to maintain optimal performance across heavy and light load scenarios while achieving zero-voltage switching
2Productivity
If resonant power conversion circuit adjusts conduction time of low-side transistor, then conversion efficiency is improved, but control complexity increases
Solution Approach 1:
The control circuit achieves multi-functionality by integrating multiple control functions into a single circuit block. It simultaneously generates high-side and low-side driving signals, adjusts conduction times, and enables zero-voltage switching without requiring separate dedicated circuits for each function, thereby limiting the increase in overall control complexity
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 enables zero-voltage switching of the high-side transistor, improving the efficiency of the resonant power conversion circuit under varying load conditions.
Implementation Method 1
resonant power conversion circuits (which including LLC resonant power conversion circuits, flyback power conversion circuits, and others) are high-efficiency and high-power density power conversion circuits
Implementation Method 2
The transformer comprises a primary coil and a secondary coil, wherein a terminal of the primary coil is coupled to the resonant node
Data Source
AI summary
A power conversion circuit includes a resonant capacitor, a transformer, a high-side transistor, a low-side transistor, and a control circuit. The resonant capacitor is coupled to the switch node. The transformer includes a primary coil coupled to the resonant capacitor and a secondary coil. The high-side transistor and the low-side transistor couples the input voltage and the ground to the switch node. The control circuit generates a first signal in response to the high-side transistor being turned on, generates a second signal in response to the high-side transistor and the low-side transistor being both turned off, and generates a third signal by comparing the second signal with a voltage threshold corresponding to the first signal. The control circuit adjusts the on-time of the low-side transistor based on the third signal, so that the high-side transistor achieves zero-voltage switching.