Switched-Mode Power Supply Feedback Circuit Mode Transition
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional switched-mode power supply systems face challenges in maintaining stability and efficiency under lightly loaded conditions, often resulting in output voltage transients as they transition between burst mode and normal mode due to differences in gain and offset of feedback signals.
Innovation Solution
A method is introduced where the switched-mode power supply operates in two modes: normal mode under moderate to heavy loads using pulse-width modulation, and burst mode under light loads, with a feedback interface circuit reconfigured to adjust gain and offset, allowing smooth transitions and reducing voltage overshoots and undershoots by switching between different configurations based on feedback signal thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a normal regulation scheme using pulse width modulated drive signal is used under lightly loaded conditions, then the output voltage can be controlled, but stability and converter efficiency deteriorate
Solution Approach 1:
The patent implements dynamic operation mode switching between normal mode and burst mode based on load conditions. The system transitions from continuous pulse width modulation under heavy loads to discontinuous burst mode operation under light loads, optimizing both stability and efficiency across different operating conditions. This dynamic adaptation resolves the contradiction by selecting the appropriate control strategy for each load level.
Solution Approach 2:
The patent changes the operating parameters of the power supply by switching between different control modes. In normal mode, continuous PWM with specific duty cycle ranges is used, while in burst mode, discontinuous switching with extended idle periods is employed. This parameter change allows the system to achieve both good voltage control and improved stability/efficiency under light loads.
2Loss of energy
If burst mode control scheme is used under light loads, then converter efficiency is improved, but output voltage becomes prone to transients during mode transitions
Solution Approach 1:
The patent applies preliminary action by pre-configuring the feedback interface circuit for the upcoming operating mode before the actual transition occurs. When transitioning from burst mode to normal mode, the feedback interface is switched to continuous monitoring configuration in advance, allowing the control system to prepare for smooth handover and avoid voltage transients. This anticipatory configuration change ensures stable output voltage during mode transitions.
3Stability of the object's composition
If the feedback interface circuit configuration is changed during mode transitions, then voltage transients are reduced, but circuit complexity increases
Solution Approach 1:
The feedback interface circuit is designed with multi-functionality to handle both normal mode and burst mode operations. The same circuit infrastructure is used across different operating modes, with reconfigurable elements that can switch between continuous monitoring and discontinuous sampling. This universal design approach minimizes the need for separate dedicated circuits for each mode, thereby reducing overall circuit complexity while maintaining voltage stability during transitions.
Data Source
AI summary
In accordance with an embodiment, a method of controlling a switched-mode power supply includes operating the switched-mode power supply in a first operating mode by monitoring a feedback signal from an output of the power supply using a feedback interface circuit in a first configuration. The method further includes determining when the feedback signal crosses a first threshold in a first direction, and transitioning the switched-mode power from the first operating to a second operating mode by switching the feedback interface circuit from the first configuration to a second configuration.