Buck-Boost Converter IC With Lossless Output Current Sensing
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Solution Overview
Problem
Existing buck-boost converters face challenges in seamlessly transitioning between buck, boost, and buck-boost modes, and lack accurate and lossless output current sensing methods.
Innovation Solution
An integrated circuit with an inductor and power switches that operate in buck, boost, or buck-boost modes, featuring an output current sensing circuit with sampling and processing circuits to generate accurate current information, allowing seamless mode transitions and precise current sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing buck-boost converter topology is used, then voltage conversion capability is achieved, but seamless mode transition between buck, boost and buck-boost modes cannot be realized
Solution Approach 1:
The patent implements dynamic mode selection by enabling the converter to automatically transition between buck mode, boost mode, and buck-boost mode based on real-time operating conditions. The control circuit dynamically adjusts the switching states of power switches to achieve seamless mode transitions, making the system adaptable to varying input voltage and load conditions while maintaining operational stability.
Solution Approach 2:
The converter topology is designed to perform multiple functions by integrating both buck and boost capabilities in a single circuit. The same power switches and inductor are utilized across different operating modes, allowing the system to function as a buck converter, boost converter, or buck-boost converter depending on the switching configuration, thereby achieving universal voltage conversion capability.
2Measurement precision
If conventional current sensing method is used, then output current information can be obtained, but sensing accuracy and losslessness cannot be simultaneously achieved
Solution Approach 1:
The patent introduces an intermediary current sensing circuit that measures the current flowing through the inductor without directly interfering with the main power path. By using this intermediary sensing approach, the system achieves accurate current measurement while minimizing energy loss, as the sensing circuit draws minimal current from the main power flow.
Solution Approach 2:
The patent replaces conventional mechanical current sensing methods (such as shunt resistors that cause voltage drops) with a magnetic field-based sensing approach. The current sensing circuit utilizes the magnetic field generated by the inductor current to derive current information without creating significant voltage drops or power losses in the main power path, thereby achieving both high accuracy and low loss.
Data Source
AI summary
An integrated circuit of a buck-boost converter working in a buck mode with a buck power switching cycle, a boost mode with a boost power switching cycle or a buck-boost mode with a buck-boost power switching cycle. The integrated circuit integrates a first power switch, a second power switch, a third power switch and a fourth power switch, and an output current sensing circuit. The buck-boost power switching cycle consists of a first buck-boost phase, a second buck-boost phase and a third buck-boost phase. The output current sensing circuit samples the current flowing through the first power switch during the second buck-boost phase and the current flowing through the fourth power switch during the third buck-boost phase so as to generate the output current information.