Resonance-Based Single Inductor DC-DC Converter
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Solution Overview
Problem
Current SIMO DC-DC converters face challenges with lower power efficiency, higher cost, cross-regulation issues, and increased electromagnetic interference due to the sharing of a single inductor among multiple outputs, which limits their performance and cost-effectiveness compared to SISO converters.
Innovation Solution
A resonance-based DC-DC converter design that eliminates input switches by using output-switch-driven operation, employing a resonant capacitor and switches to manage inductor current through phases of operation, allowing for zero voltage and current switching, and utilizing low-voltage transistors to reduce power losses and electromagnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If SIMO DC-DC converters share a single inductor among multiple outputs, then the number of external inductors is reduced, but power efficiency decreases and cross-regulation issues increase
Solution Approach 1:
The patent segments the inductor current into distinct phases for each output, with dedicated switch pairs controlling current flow to each output capacitor. This segmentation allows independent control of each output while sharing the single inductor, resolving the cross-regulation issue by preventing simultaneous current demands from multiple outputs.
Solution Approach 2:
The patent employs periodic sequential switching where each switch pair operates in alternating cycles. The controller sequentially activates switch pairs for different outputs in a periodic manner, ensuring that current is delivered to each output in discrete phases rather than simultaneously, thereby maintaining power efficiency while serving multiple outputs.
2Device complexity
If SIMO DC-DC converters share a single inductor among multiple outputs, then component count is reduced, but cross-regulation problems increase
Solution Approach 1:
The patent segments the control function into multiple independent switch pairs, each dedicated to a specific output. This segmentation isolates the control paths for each output, preventing voltage fluctuations at one output from affecting others, thereby maintaining voltage regulation stability despite using a shared inductor.
Solution Approach 2:
The controller monitors the voltage at each output and uses feedback signals to adjust the switching timing and duration of each switch pair. This feedback mechanism ensures that each output maintains stable voltage regulation even when load conditions change, resolving the cross-regulation problem while keeping component count low.
3Ease of operation
If traditional DC-DC converters use input switches, then current control is simplified, but electromagnetic interference and power losses increase
Solution Approach 1:
The patent inverts the traditional switch placement by moving switches from the input side to the output side of the inductor. Instead of controlling current entry to the inductor, the switches control current exit from the inductor to each output. This inversion reduces EMI because the switches operate at lower voltage nodes and the inductor current is already established before switching occurs.
Solution Approach 2:
The patent introduces a controller as an intermediary that coordinates the switching of multiple switch pairs sequentially. This intermediary manages the timing and duration of each switch pair's operation, enabling sophisticated current control without requiring high-power input switches, thereby reducing EMI and power losses while maintaining ease of 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
This design achieves higher system power efficiency, lower system cost, reduced cross-regulation, and lower electromagnetic interference, enabling the use of more low-voltage transistors in high-voltage converters while scaling voltage ratings independently of input voltage, thus improving overall performance and reducing costs.
Implementation Method 1
A resonance-based DC-DC converter design that eliminates input switches by using output-switch-driven operation, employing a resonant capacitor and switches to manage inductor current through phases of operation, allowing for zero voltage and current switching
Data Source
AI summary
A resonance-based DC-DC converter for converting a DC input voltage to a first DC output voltage (VOUT1) on a output conductor (9) includes an inductor (L) having a first terminal connected to a source (2) of a DC input voltage (VIN) and a second terminal coupled to a first conductor (4) and a capacitor (CRES) having a first terminal coupled to the first conductor. A first switch (SW1) is coupled between the resonance conductor and the output conductor to conduct inductor current (IL) into the output conductor during a first phase (Phase1). A second switch (SW2) is coupled between a second terminal of the capacitor and the output conductor to conduct inductor current through the capacitor into the output conductor (9) during a second phase (Phase2). A third switch (SW3) is coupled between the second terminal (31) of the capacitor and a first reference voltage (GND) to conduct inductor current from a source of the first reference voltage through the capacitor to the input voltage (VIN) during a third phase (Phase3).