Valley Detection Switching Controller for Resonant Converter Loss Reduction
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Solution Overview
Problem
General quasi-resonant converters increase switching frequency and power consumption when input voltage exceeds a certain level or output load becomes small, requiring complex circuit configurations to detect valley points in resonance waveforms, thereby increasing production costs and layout area.
Innovation Solution
A converter with a simple circuit that includes a first switch, an energy transmitting element, and a switching controller comprising a valley detector and a PWM controller to detect the valley of a resonance waveform and turn on the switch accordingly, minimizing switching losses without increasing production costs or layout area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the converter uses a general quasi-resonant switching method to minimize power consumption, then switching losses are reduced at normal operating conditions, but switching frequency and power consumption increase significantly when input voltage exceeds predetermined level or output load becomes very small
Solution Approach 1:
The converter dynamically adjusts the valley detection threshold based on operating conditions. The switching controller compares the resonant waveform valley with a dynamically adjustable reference voltage that changes according to input voltage levels and load conditions, allowing the system to adaptively select appropriate switching points across different operating ranges rather than using a fixed threshold
Solution Approach 2:
The invention changes the detection parameter from fixed first-valley detection to flexible multi-valley detection with adjustable threshold. By modifying the reference voltage parameter and enabling detection at different valley points (first, second, or third valley), the system optimizes switching timing to maintain low switching frequency and power consumption across varying input voltages and load conditions
2Loss of energy
If the converter detects the valley of the resonance waveform using existing techniques to avoid increasing switching frequency, then power consumption is reduced, but the circuit configuration becomes complicated, increasing production cost and layout area
Solution Approach 1:
The switching controller is designed to perform multiple functions: it generates PWM signals for switch control, detects resonance waveform valleys, compares valley points with reference voltages, and generates appropriate drive signals. This multi-functional integration eliminates the need for separate dedicated valley detection circuits, reducing overall system complexity while maintaining the ability to detect and respond to resonance valleys effectively
Solution Approach 2:
The switching controller utilizes its own internal comparison and control mechanisms to detect and respond to resonance waveform valleys without requiring external dedicated detection hardware. The controller self-regulates by comparing the resonant waveform with reference voltages and automatically adjusts switching timing, making the system self-sufficient and reducing external circuit requirements
Data Source
AI summary
A converter is provided including: a first switch; an energy transmitting element for converting input energy into output energy according to the switching of the first switch; and a switching controller for detecting a time when a voltage between a first terminal and a second terminal of the first switch reaches a valley of a resonance waveform, and actuating the first switch corresponding to one of the detected valleys of the resonance waveform. The switching controller includes: a valley detector for changing the state of the output signal whenever a voltage between a first terminal and a second terminal of the first switch reaches a valley of the resonance waveform; and a PWM controller for actuating the first switch corresponding to an output signal of the valley detector.