Buck Boost Converter Linear Transition Control
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Solution Overview
Problem
Buck boost converters experience non-linear transitions between buck and boost modes, leading to overshoot or undershoot voltage conditions due to the reliance on input and output voltage for mode transitions, which existing solutions fail to address effectively.
Innovation Solution
The implementation of a compensator signal and offset boost ramp voltage to generate linear PWM signals, allowing the buck boost converter to operate linearly by using only two switches during transitions, independent of input voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional buck boost converter transitions are used, then mode switching between buck and boost is achieved, but non-linear transitions cause voltage overshoot or undershoot
Solution Approach 1:
The patent inverts the conventional approach by using a single ramp signal for both buck and boost modes instead of separate control schemes. The PWM generator compares a single ramp signal against current sense signals to control both modes, fundamentally changing the control architecture to achieve linear transitions and eliminate voltage overshoot/undershoot issues.
2Adaptability or versatility
If four switches are used in full bridge configuration during transitions, then mode switching is enabled, but device complexity increases
Solution Approach 1:
The patent extracts and eliminates the need for four switches in full bridge configuration by using a simplified control scheme with fewer switches. The single ramp signal approach allows mode transitions to be achieved with reduced switching complexity, removing unnecessary components while maintaining adaptability between buck and boost modes.
Data Source
AI summary
A voltage regulator, comprises first circuitry for generating an output voltage responsive to an input voltage and a plurality of switching control signal. Switching control circuitry generates the switching control signals responsive to the output voltage and at least one of a buck ramp signal and a boost ramp signal. Voltage ramp generation circuitry generates each of the buck ramp signal and the boost ramp signal. The boost ramp signal comprises the buck ramp signal offset by the peak value of the buck ramp signal.