Switched Common-Mode Current Control for SIMO Power Converters
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Solution Overview
Problem
Single-inductor-multiple-output (SIMO) power converters face challenges in accurately regulating multiple output voltages without compromising power conversion efficiency, often resulting in common-mode errors or reduced efficiency due to freewheeling periods.
Innovation Solution
A switched common-mode current control method that adjusts the regulation of output voltages based on their relative values to reference voltages, using a regulation circuit with error amplifiers, comparators, and a logic circuit to determine the appropriate error voltage for each output voltage, allowing for efficient regulation without freewheeling intervals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a single inductor is used to regulate multiple output voltages, then circuit space efficiency is improved, but manufacturing precision of output voltages deteriorates due to common-mode errors
Solution Approach 1:
The patent segments the regulation process by separating common-mode current regulation from individual output voltage regulation. The controller divides the regulation into stages: first regulating the common-mode current through the single inductor, then individually regulating each output voltage based on the regulated common-mode current. This segmentation allows accurate multi-output regulation while maintaining circuit space efficiency.
Solution Approach 2:
The patent introduces common-mode current as an intermediary variable to mediate between the single inductor and multiple outputs. By regulating the common-mode current flowing through the shared inductor and then distributing it to individual outputs with separate regulation stages, the system achieves both space efficiency and voltage accuracy.
2Manufacturing precision
If traditional regulation methods are used for SIMO converters, then output voltage regulation is achieved, but power conversion efficiency deteriorates due to freewheeling periods
Solution Approach 1:
The patent eliminates freewheeling periods by implementing continuous useful action through synchronized switching. The controller coordinates the switching of multiple switches such that the inductor current continuously delivers power to the outputs without idle freewheeling intervals. This maintains continuous useful energy transfer from the single inductor to multiple outputs, improving power conversion efficiency while maintaining voltage regulation.
3Device complexity
If a single inductor is used for multiple outputs, then device complexity is reduced, but reliability of voltage regulation deteriorates
Solution Approach 1:
The patent segments the control into hierarchical stages: common-mode current regulation followed by individual output voltage regulation. This segmented approach allows the system to first establish stable common-mode current through the shared inductor, then independently regulate each output voltage, thereby maintaining regulation reliability despite the simplified single-inductor structure.
Solution Approach 2:
The patent implements multi-stage feedback control where the controller monitors both the common-mode current and individual output voltages. The feedback loops adjust switching duties at each stage to maintain regulation stability, compensating for the reduced structural redundancy of using a single inductor for multiple outputs.
Data Source
AI summary
A power converter includes a voltage source for generating an input voltage, and a regulation circuit for generating a set of output voltages based on the input voltage. The regulation circuit regulates the set of output voltages in different manners based on whether the set of output voltages is greater or less than a set of corresponding reference voltages, respectively. If one or more output voltages are less than one or more of the corresponding reference voltages, the regulation circuit regulates only those one or more output voltages during a current regulation interval based on an error voltage related to one or more differences between the one or more output voltages and the corresponding one or more reference voltages, respectively. If all output voltages are greater than the corresponding reference voltages, the regulation circuit regulates only the output voltage associated with the largest load current during the current regulation interval.