Interleaved Multi-Phase Buck-Boost Converter for Thermal and EMI Limits
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Solution Overview
Problem
Conventional buck-boost switching converter circuits face thermal limitations and increased complexity due to high inductor currents during boost operation, leading to reduced power delivery capability and increased size and cost, as well as electromagnetic interference (EMI) challenges.
Innovation Solution
A multi-phase buck-boost switching converter circuit with a reduced number of power switches and switching nodes, where the multi-phase boost circuit stage operates out of phase with a single-phase buck circuit stage, using interleaved inductor currents and peak inductor current detection to balance currents and reduce losses, thereby addressing thermal and complexity issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a conventional buck-boost switching converter circuit is used, then the circuit can provide regulated voltage output, but the thermal limitations and high inductor currents reduce power delivery capability
Solution Approach 1:
The converter is divided into multiple parallel boost circuits (multi-phase configuration), where each phase handles a portion of the total current. This segmentation distributes the thermal load across multiple components, reducing peak temperatures and enabling higher overall power delivery without exceeding thermal limits of individual elements.
2Power
If high inductor currents are used during boost operation, then power delivery is increased, but circuit complexity and size increase
Solution Approach 1:
Multiple boost circuits are merged in parallel configuration, sharing common components such as the output capacitor and control logic. This merging approach achieves current distribution for reduced complexity while maintaining high power delivery capability, as the parallel structure naturally divides current among phases without requiring complex current management circuitry.
3Power
If high inductor currents are used during boost operation, then power delivery is increased, but inductor size and cost increase
Solution Approach 1:
The total inductance requirement is segmented across multiple smaller inductors operating in parallel. Each inductor carries only a fraction of the total current, allowing the use of smaller, lighter magnetic components while maintaining the same overall power handling capability. This segmentation reduces both individual and total inductor size and cost.
4Object-affected harmful factors
If conventional single-phase operation is used, then circuit simplicity is maintained, but EMI noise increases
Solution Approach 1:
The multi-phase converter employs periodic switching actions with different phases operating at offset timing. This periodic interleaved operation distributes electromagnetic interference events over time, reducing peak EMI noise levels. The phase-offset switching creates a more continuous and balanced current waveform that reduces high-frequency noise compared to single-phase operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enhances the maximum power delivery capability, reduces system complexity and cost, and minimizes EMI noise, while maintaining balanced inductor currents without additional servo-loops.
Implementation Method 1
switching converter circuits that use switching to energize and de-energize a magnetic circuit element (e.g., an inductor)
Data Source
AI summary
A multi-phase buck-boost converter circuit comprises a buck circuit stage, a boost circuit stage, and a control circuit. The buck circuit stage is connected to an input of the buck-boost converter circuit to receive an input voltage. The boost circuit stage includes multiple boost circuits connected in parallel. The boost circuit stage is coupled to the buck circuit stage and an output of the multi-phase buck-boost converter circuit. Each boost circuit includes an inductor coupled to the buck circuit stage. The control circuit operates the multiple boost circuit stages out of phase with respect to each other in a boost mode, operates the buck circuit stage in a buck mode, and operates the multiple boost circuit stages out of phase with respect to each other and operates the buck circuit stage in a buck-boost mode.