Resonant Power Supply Converter Light-Load Control
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Solution Overview
Problem
Resonant type power supply controllers often produce audible noise and inefficiencies due to varying load conditions, causing mechanical vibrations in the resonant circuit.
Innovation Solution
A power supply control circuit that switches high-side and low-side transistors in a resonant LLC type power supply system, utilizing a light-load operating mode with a sequence of drive intervals and non-switching intervals to adjust pulse sets based on load conditions, thereby reducing audible noise and improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the power supply controller operates with varying frequency based on load conditions, then the power supply adapts to different load requirements, but mechanical vibrations occur causing audible noise
Solution Approach 1:
The patent applies periodic action by implementing a fixed frequency operating mode where the controller operates at a predetermined frequency regardless of load conditions. This is achieved through a frequency lock mechanism that maintains consistent switching frequency, thereby eliminating variable frequency-induced mechanical vibrations and audible noise while still adapting to load changes through pulse width modulation
Solution Approach 2:
The patent changes the frequency parameter from variable to fixed while compensating for load variations through duty cycle adjustment. The controller maintains a predetermined frequency by locking the oscillation frequency, and adapts to different load conditions by modifying the pulse width or duty cycle rather than changing frequency, thus resolving the contradiction between adaptability and noise reduction
2Loss of energy
If the power supply controller reduces operating frequency to deliver less power, then power delivery matches reduced load requirements, but mechanical vibrations increase causing audible noise
Solution Approach 1:
The patent implements periodic action with fixed frequency operation, maintaining a predetermined switching frequency regardless of power level adjustments. The controller achieves variable power delivery through pulse skipping or duty cycle modulation while keeping the frequency constant, preventing mechanical vibrations and audible noise that would result from frequency reduction
Solution Approach 2:
The patent applies dynamics by making the duty cycle or pulse width variable while keeping frequency fixed. The controller dynamically adjusts the on-time or pulse width according to load requirements, allowing efficient power delivery at reduced levels without changing frequency, thus avoiding the mechanical vibrations and audible noise associated with frequency reduction
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 effectively reduces audible noise and improves efficiency by maintaining a frequency below audible ranges and optimizing power delivery to the load, while maintaining a stable resonant operating mode.
Implementation Method 1
a resonant circuit that was driven by the control
Implementation Method 2
resonant type power supply controller... resonant circuit that was driven by the control
Data Source
AI summary
In one embodiment, a resonant converter circuit may be formed to include a light-load control circuit that forms a sequence to control one or more transistors wherein the sequence includes a drive interval having a drive pattern to drive the one or more transistors and a subsequent Off-interval wherein the one or more transistors are switched. A first circuit of the light-load control circuit may be configured to form the drive pattern as a repeated sequence of a pulse set that sequentially enables the one or more transistors with a base set followed by a number of non-switching intervals wherein each non-switching interval is a period of a signal formed in response to driving the one or more transistors with the base set.