Multi-Phase DC to DC Converter Controller for Balanced Inductor Currents
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Solution Overview
Problem
Conventional multi-phase DC to DC converters experience unbalanced inductor currents due to independent controllers generating PWM signals with different pulse widths, leading to errors in output voltage and reduced performance.
Innovation Solution
A controller that generates phase-shifted PWM signals with ramp signals of the same slope, comparing these signals with a preset reference to balance inductor currents by controlling their on-time states, ensuring equal ripple magnitudes across inductive components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If independent controllers are used to control duty cycles of PWM signals, then device complexity is reduced, but inductor current balance deteriorates
Solution Approach 1:
The patent merges multiple independent controllers into a single integrated controller that generates phase-shifted PWM signals with synchronized ramp signals. This unified controller structure ensures that all phases share the same control logic and timing reference, eliminating the current imbalance issue while maintaining manageable system complexity through modular phase control circuits.
2Adaptability or versatility
If PWM signals with different pulse widths are generated, then adaptability to different loading conditions is improved, but inductor current balance deteriorates
Solution Approach 1:
The patent implements dynamic phase-shifted PWM control where the duty cycles of different phases are adjusted in real-time based on synchronized ramp signal comparisons. Each phase can have different pulse widths to adapt to loading conditions, while the synchronized ramp signals ensure that these differences do not cause current imbalance, achieving both adaptability and stability dynamically.
3Stability of the object's composition
If phase-shifted PWM signals are generated with synchronized ramp signals, then inductor current balance is improved, but device complexity increases
Solution Approach 1:
The patent segments the control function into modular phase control circuits, each handling one phase with its own PWM generation and ramp signal comparison. This segmentation allows the complex synchronized control to be implemented through repeated, standardized circuit blocks rather than a monolithic complex controller, making the system more manageable and easier to implement while achieving balanced inductor currents.
Data Source
AI summary
In a controller for a DC to DC converter, PWM signal generating circuitry generates a set of PWM signals phase-shifted relative to one another, and controls states of the PWM signals according to a set of control signals. Each PWM signal of the PWM signals has an on-time state and an off-time state. Ramp signal generating circuitry, coupled to the PWM signal generating circuitry, generates a set of ramp signals having substantially the same ramp slope. Each ramp signal of the ramp signals is generated in response to detecting an on-time state of a corresponding PWM signal of the PWM signals. Additionally, a comparing circuit, coupled to the PWM and ramp signal generating circuitry, alternately compares the ramp signals with a preset reference to generate the control signals. A corresponding control signal of the control signals changes the corresponding PWM signal from the on-time state to an off-time state.