Buck-Boost Converter Mode Control via Inductor Current Slope
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Solution Overview
Problem
Existing DC-DC voltage converters with windowed-type control require comparators to monitor input and output voltages, leading to substantial power consumption and reduced operating intervals between battery charge events, while windowless control is slow to respond to voltage changes.
Innovation Solution
A voltage converter that uses the slope of inductor current to control transitions between boost, buck, and buck-boost operating modes without the need for comparators, enabling quick responses to voltage changes by enabling comparators only when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If windowed-type control with comparators is used to monitor input and output voltages, then the converter can accurately determine operating modes, but power consumption increases substantially
Solution Approach 1:
The patent extracts the voltage monitoring function from continuous comparator operation and implements it only when needed through inductor current slope analysis. The controller monitors inductor current slope to infer voltage relationships, eliminating the need for continuous comparator-based voltage monitoring and reducing power consumption while maintaining mode detection accuracy.
Solution Approach 2:
The inductor current itself provides the monitoring function by whose slope the controller determines the relative voltage levels. The system uses its own operating parameters (inductor current slope) to make control decisions, eliminating the need for separate voltage sensing comparators and reducing overall power consumption.
2Use of energy by moving object
If windowless control is used to eliminate comparators, then power consumption is reduced, but response speed to voltage changes becomes slow
Solution Approach 1:
The patent implements feedback by continuously monitoring the inductor current slope, which directly reflects the voltage difference between input and output. This feedback mechanism enables the controller to rapidly detect voltage changes and respond accordingly, achieving fast response without continuous comparator operation, thus reducing power consumption while maintaining speed.
3Measurement precision
If comparators are continuously on to monitor voltage levels, then mode detection is accurate, but operating intervals between battery charge events are reduced
Solution Approach 1:
The patent implements periodic action by enabling comparator-based voltage monitoring only during transitions or when inductor current slope indicates uncertain mode conditions. During stable operation, the system relies on inductor current slope analysis, reducing comparator activity to periodic intervals and thereby extending battery operating intervals between charge events while maintaining accurate mode detection when needed.
Data Source
AI summary
Apparatus and methods for controlling voltage converter are provided. In an example, a switched-mode DC-DC voltage converter can include an inductor, at least four switches coupled to the inductor and configured to direct current through the inductor to provide a desired output voltage at an output voltage terminal of the voltage converter using an input voltage supply and a ground reference of the converter, and a controller circuit, configured to receive an indication of inductor current through the inductor and to use the slope of the inductor current to control a change between two operating modes of a group of operating modes that include a boost operating mode, a buck operating mode, and a buck-boost operating mode.