Power Converter Spectrum Spreading Control Mechanism
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Solution Overview
Problem
Power converters experience reduced operational efficiency and normal operation due to high electromagnetic interference (EMI) generated by switch components operating at high frequencies.
Innovation Solution
A power converter with a spectrum spreading control mechanism, which divides the original switching frequency into multiple frequency bands within a switching frequency range, using a buffer circuit to determine buffering ratios for each frequency band and an on-time determining circuit to adjust switching times based on buffered voltage signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If switch components operate at high frequency to improve power converter performance, then power conversion efficiency is improved, but electromagnetic interference (EMI) increases causing operational failures
Solution Approach 1:
The patent segments the original single switching frequency into multiple frequency bands by dividing the switching frequency range into first, second, and third frequency bands. The control circuit switches between different frequency bands based on operating conditions, effectively segmenting the EMI spectrum and reducing peak EMI energy at any single frequency.
Solution Approach 2:
The patent implements dynamic switching frequency adjustment where the control circuit dynamically selects between different frequency bands (first, second, or third frequency band) based on real-time operating conditions. This dynamic adaptation allows the system to maintain high efficiency while avoiding EMI-prone frequency ranges.
2Volume of moving object
If switching frequency is increased to reduce component size, then power density is improved, but EMI signal strength increases disrupting normal operation
Solution Approach 1:
The patent changes the switching frequency parameter dynamically by selecting from multiple frequency bands based on operating conditions. The control circuit monitors system state and adjusts the switching frequency within the switching frequency range, transforming a fixed parameter into a variable one to simultaneously achieve small component size and low EMI.
3Device complexity
If single frequency switching is used to simplify control, then control circuit complexity is reduced, but EMI cannot be effectively managed
Solution Approach 1:
The control circuit is segmented into multiple operational modes corresponding to different frequency bands. Rather than implementing a complex continuous frequency modulation system, the patent divides control into discrete frequency band selections (first, second, third frequency bands), simplifying the control logic while achieving EMI reduction through frequency diversity.
Data Source
AI summary
A power converter having a spectrum spreading control mechanism is provided. In the power converter, a buffer circuit, according to a plurality of energy upper limit values respectively of a plurality of frequency bands falling within a switching frequency range, determines a plurality of buffering ratios corresponding respectively to the plurality of frequency bands. In the power converter, the buffer circuit buffers a voltage signal from an inductor based on one of the plurality of buffering ratios that corresponds to one of the plurality of frequency bands within which a switching frequency of the high-side switch and the low-side switch currently falls. In the power converter, an on-time determining circuit determines an on-time of the high-side switch and an on-time of the low-side switch, according to the buffered voltage signal.