Multiphase Converter Phase Current Balancing via Common Loop
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Solution Overview
Problem
Multiphase DC/DC converters face challenges in balancing phase currents due to component value tolerances and aging, leading to unbalanced currents and increased CPU processing load when using individual current-loop control, which results in overstress and reduced converter life.
Innovation Solution
A method and system that alternately connect phases to an input current and sample at a common node to adjust intervals, generating trigger signals to synchronize sampling and adjust duty cycles to minimize inequality in input current samples, allowing for balanced phase currents using a common current loop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If individual current-loop control is used per phase, then phase current balance is improved, but device complexity and CPU processing load increase
Solution Approach 1:
The patent merges multiple individual current-loop controls into a single common current loop that controls all phases. Instead of having separate control circuits for each phase, a unified control mechanism manages all phases, reducing component count and complexity while maintaining current balance through shared sensing and control logic.
Solution Approach 2:
The patent implements a universal current sensing mechanism that serves all phases through a single sensor placed at the common input node. This multi-functional approach allows one sensor to monitor currents for multiple phases simultaneously, eliminating the need for separate sensors and reducing overall system complexity.
2Manufacturing precision
If individual current-loop control is used per phase, then phase current balance is improved, but CPU processing load increases
Solution Approach 1:
The patent combines multiple individual current control processing tasks into a single unified processing routine. By merging the control logic for all phases into one common loop, the CPU handles phase current balance as a single integrated task rather than multiple separate tasks, significantly reducing processing load and computational overhead.
3Device complexity
If common current control is used for all phases, then device complexity and CPU load are reduced, but phase current balance deteriorates
Solution Approach 1:
The patent applies local quality by placing the current sensor at a specific strategic location - the common input node where all phases converge. This localized sensing position allows the common control loop to accurately detect current imbalances in each phase individually, enabling precise balance control without requiring separate sensors for each phase.
Solution Approach 2:
The patent implements a feedback mechanism where the single current sensor continuously monitors the input current to each phase, and the controller uses this feedback information to dynamically adjust switching duty cycles for each phase. This closed-loop feedback ensures that despite using a common control structure, the system can detect and correct current imbalances to maintain phase balance.
4Productivity
If common current control is used for all phases, then CPU processing load is reduced, but converter life is reduced due to phase overstress
Solution Approach 1:
The patent uses real-time feedback from the current sensor to continuously monitor phase current levels and detect imbalances. The controller processes this feedback to dynamically adjust duty cycles, preventing any single phase from being overloaded. This active feedback control ensures equitable current distribution across all phases, preventing overstress and extending converter life while maintaining low CPU load through efficient processing.
Data Source
AI summary
Systems and methods for balancing phase currents of the phases of a multiphase converter include alternately connecting the phases during respective intervals to an input current and sampling, at a node of the multiphase converter that is common to the phases, the input current provided to the phases to obtain respective input current samples for the phases. While the input current samples are unequal, the intervals are adjusted to minimize inequality of the input current samples and thereby balance the phase currents.