Adjustable-Phase Voltage Converter for Inductor Zero-Current Switching
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Solution Overview
Problem
Existing switched mode power supply converters, particularly those operating in PFM mode, face challenges in ensuring zero current through the inductive element at the beginning and end of each operating cycle, leading to inefficiencies in energy accumulation and restitution phases.
Innovation Solution
A voltage converter is configured to adjust the duration of the energy restitution phase by comparing a voltage ramp with a reference voltage, where the slope of the ramp depends on the sign of the current in the inductor at the end of the previous cycle, allowing for adaptive adjustment of the slope to achieve zero current through the inductor at the end of each cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the duration of energy restitution phase is fixed, then the converter operation is simple, but the current through the inductor cannot be ensured to be zero at the end of each cycle
Solution Approach 1:
The patent implements a feedback mechanism where the actual current through the inductor is measured and compared with the reference voltage to determine the duration of the energy restitution phase. This feedback loop ensures that the current returns to zero at the end of each cycle by adjusting the phase duration based on the measured current state, thereby resolving the contradiction between reliability and complexity.
Solution Approach 2:
The converter uses its own current measurement to automatically adjust the energy restitution phase duration without external intervention. The control circuit self-regulates by using the measured current information to determine when to terminate the restitution phase, ensuring zero current at the end of each cycle while maintaining autonomous operation.
2Productivity
If the slope of voltage ramp is fixed, then the phase duration determination is simple, but the energy transfer efficiency is reduced
Solution Approach 1:
The patent employs a dynamic voltage ramp with variable slope instead of a fixed slope. The slope of the voltage ramp is adjusted based on the measured current state to optimize the energy transfer efficiency. This dynamic adjustment allows the system to adapt to different operating conditions, improving productivity while requiring a more complex ramp generation circuit.
Solution Approach 2:
The system changes the parameter of voltage ramp slope dynamically during operation. By varying the slope parameter based on the measured current, the system optimizes the comparison process and energy transfer efficiency, resolving the contradiction between productivity and device complexity.
3Reliability
If the phase duration is determined by fixed comparison, then the control is simple, but the current zero-crossing cannot be achieved
Solution Approach 1:
The patent uses feedback from the measured current to determine the phase duration. The measured current is compared with the voltage ramp, and this feedback loop ensures accurate detection of the current zero-crossing point, thereby achieving reliable current zero-crossing while requiring precise measurement capabilities.
Solution Approach 2:
The patent replaces direct mechanical current measurement with an electrical comparison method. Instead of directly measuring current zero-crossing, the system compares the voltage ramp (which reflects current state) with a reference, substituting a more precise electrical measurement approach that improves zero-crossing accuracy.
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 solution ensures efficient energy transfer by ensuring zero current through the inductor at the end of each cycle, improving the overall efficiency and accuracy of the energy accumulation and restitution phases in switched mode power supply converters.
Implementation Method 1
During the energy accumulation phase, the current through the inductive element increases
Implementation Method 2
During the energy restitution phase, the current through the inductive element decreases
Data Source
AI summary
In an embodiment, a voltage converter is configured to operate by a succession of operating cycles, each cycle comprising an energy accumulation phase and an energy restitution phase, wherein the converter is further configured to determine a duration of one of the phases by comparing a voltage ramp and a first reference voltage, and wherein a slope of the voltage ramp depends on a sign of a current in an inductor at an end of a previous operating cycle.