Adaptive LLC Burst Frequency for Low Power Standby
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Solution Overview
Problem
Conventional LLC converters face challenges in meeting standby power consumption, output voltage ripple, and dynamic response requirements due to fixed switching frequency in low power modes, leading to excessive energy delivery and slower dynamic responses, especially under varying input voltages and loads.
Innovation Solution
Implementing a low power standby mode control method that involves bursting the LLC converter with a predefined burst on-time, where the switching frequency is decreased and then increased in a controlled manner, and adjusting the frequency based on load conditions and input voltage, using a combination of fixed burst-on time and adaptive LLC burst frequency techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the LLC converter operates at a fixed switching frequency in low power standby mode, then the control is simple, but the standby power consumption and output voltage ripple requirements cannot be met under varying input voltage and load conditions
Solution Approach 1:
The patent implements dynamic switching frequency adjustment in the LLC converter during standby mode. The controller varies the switching frequency based on real-time detection of input voltage and load conditions, transforming the fixed-frequency operation into adaptive dynamic operation. This resolves the contradiction by enabling the system to optimize energy efficiency without requiring complex manual control configurations.
Solution Approach 2:
The patent changes the operating parameter (switching frequency) of the LLC converter based on different operating conditions. By detecting input voltage levels and load conditions, the controller adjusts the switching frequency parameter to achieve optimal standby power consumption and output voltage ripple performance across varying conditions, rather than operating at a single fixed frequency.
2Ease of operation
If the LLC converter operates at a fixed switching frequency, then the device is easy to operate, but the dynamic response to load changes is slower
Solution Approach 1:
The patent implements dynamic switching frequency adjustment in the LLC converter during standby mode. The controller varies the switching frequency based on real-time detection of input voltage and load conditions, transforming the fixed-frequency operation into adaptive dynamic operation. This resolves the contradiction by enabling the system to optimize energy efficiency without requiring complex manual control configurations.
Solution Approach 2:
The patent incorporates feedback mechanisms where the controller continuously monitors output voltage and load conditions, then adjusts the switching frequency accordingly. This closed-loop feedback enables fast dynamic response to load changes while maintaining ease of operation through automatic control, eliminating the need for manual intervention.
3Device complexity
If the LLC converter uses a fixed burst-on time, then the control is simplified, but excessive energy is delivered leading to higher standby power losses
Solution Approach 1:
The patent changes the operating parameter (switching frequency) of the LLC converter based on different operating conditions. By detecting input voltage levels and load conditions, the controller adjusts the switching frequency parameter to achieve optimal standby power consumption and output voltage ripple performance across varying conditions, rather than operating at a single fixed frequency.
4Stability of the object's composition
If the secondary-side control is saturated due to fixed frequency operation, then the system is stable, but the output voltage drop increases and dynamic response slows
Solution Approach 1:
The patent implements dynamic switching frequency adjustment in the LLC converter during standby mode. The controller varies the switching frequency based on real-time detection of input voltage and load conditions, transforming the fixed-frequency operation into adaptive dynamic operation. This resolves the contradiction by enabling the system to optimize energy efficiency without requiring complex manual control configurations.
Solution Approach 2:
The patent incorporates feedback mechanisms where the controller continuously monitors output voltage and load conditions, then adjusts the switching frequency accordingly. This closed-loop feedback enables fast dynamic response to load changes while maintaining ease of operation through automatic control, eliminating the need for manual intervention.
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 ensures stringent compliance with standby power consumption, output voltage ripple, and dynamic response requirements, reducing standby power losses and improving responsiveness to load changes across different resonant component tolerances and conditions.
Implementation Method 1
A switching (full or half) bridge on the primary side generates a square waveform that excites the LLC tank circuit, which in response outputs a resonant sinusoidal current
Implementation Method 2
LLC converters have a topology that utilizes a combination of two inductors and one capacitor ('LLC') on the primary side of the converter... outputs a resonant sinusoidal current
Data Source
AI summary
A power supply includes a PFC (power factor correction) circuit, an LLC converter and a controller. The controller is operable to burst the LLC converter for a predefined burst on-time and at a default frequency when the power supply is in a low power standby mode, and adjust the frequency at which the LLC converter is switched during the predefined burst on-time based on load conditions and an input voltage to the LLC converter.