Buck-Boost Regulator Mode Bounce Suppression via Hysteresis
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Solution Overview
Problem
Buck-boost switching regulators face inefficiencies and mode bounce issues during operation mode transitions, leading to high switch driving losses, output ripples, and reduced efficiency, especially at light load conditions.
Innovation Solution
Implementing a method that combines masking logic and offset feedback to provide hysteresis, reducing the likelihood of mode changes by shifting transition points and using pulse width monitoring to control mode transitions, thereby minimizing ripples and switching losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If multiple operation modes are used to improve efficiency, then conversion efficiency is improved, but mode bounce occurs causing output ripples and instability
Solution Approach 1:
The patent implements dynamic operation modes that can transition between buck, boost, and buck-boost modes based on real-time operating conditions. The controller dynamically selects the appropriate mode to maintain high efficiency across different input voltage and load conditions, resolving the contradiction between efficiency improvement and operational stability.
Solution Approach 2:
The patent employs feedback control mechanisms where the controller continuously monitors operating parameters and adjusts the operation mode accordingly. This feedback system prevents mode bounce by detecting transition conditions and stabilizing the output voltage during mode changes, thus maintaining both efficiency and stability.
2Loss of energy
If operation mode transitions are implemented to reduce switching losses, then efficiency is improved, but output ripples and glitches increase during transition
Solution Approach 1:
The patent prepares for mode transitions in advance by predicting when transitions will occur based on monitored parameters. The controller initiates preparatory actions before the actual transition, such as adjusting duty cycles or pre-charging/discharging capacitors, to minimize output ripples and glitches during the switching event.
Solution Approach 2:
The patent implements rapid mode transitions that occur quickly rather than gradually, reducing the time during which ripples and glitches can manifest. By rushing through the transition period with optimized switching sequences, the system minimizes the duration of harmful output disturbances while still achieving the efficiency benefits of mode changes.
3Stability of the object's composition
If offset voltage is increased to prevent mode bounce, then mode stability is improved, but output ripple increases during transition
Solution Approach 1:
The patent dynamically adjusts the offset voltage parameter based on the operating conditions and transition state. Rather than using a fixed large offset voltage that causes excessive ripple, the system modifies the offset voltage magnitude and timing to provide just enough stability during transitions while minimizing output ripple generation.
Data Source
AI summary
The present disclosure relates to methods and circuits to achieve a buck-boost switching regulator that allows changing operation modes without causing large output ripples during transition of operation modes Increased error amplifier output voltage range over which the converter stays in its present operating mode (buck or boost or buck-boost), resulting in hysteresis between error amplifier output voltage and output voltage). The larger the hysteresis, the smaller will be the likeliness of having to switch between modes. A first embodiment is combining masking logic applied to signals driving the switches of the switching regulator and offset feedback to outputs of the error amplifier in order to providing hysteresis to suppress operation mode bounce and to minimize ripples while a second embodiment is monitoring pulse width of PWM pulses by a pulse width checker.