DC/DC Converter Frequency Adjustment for Magnetic Coupling
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Solution Overview
Problem
Miniaturization of true wireless stereo devices leads to unexpected magnetic coupling between the magnet and inductor in power converters, causing significant inductance variations and resulting in reduced output voltage and current due to longer circuit response times.
Innovation Solution
A DC-to-DC power converter with a PWM controller that adjusts the switching frequency in response to specific events detected by the switching and output sensing nodes, mitigating the effects of magnetic coupling by dynamically managing the inductive current ripple range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the distance between the magnet and inductor is reduced to miniaturize TWS devices, then the device size is reduced, but unexpected magnetic coupling occurs causing inductance to vary significantly and rapidly
Solution Approach 1:
The patent applies dynamics by making the switching frequency adjustable and adaptive rather than fixed. The PWM controller dynamically changes the switching frequency based on detected inductance variations, allowing the system to adapt to changing magnetic coupling conditions while maintaining stable operation despite miniaturization-induced proximity effects
Solution Approach 2:
The patent changes the operating parameter (switching frequency) in response to detected inductance variations. When magnetic coupling causes inductance to drop below a threshold, the controller increases switching frequency to compensate, thereby maintaining stable power converter performance despite the physical proximity of magnetic components
2Reliability
If the circuit response time is increased to handle inductance variations, then the inductance changes can be managed, but the output voltage drops significantly and average current is reduced
Solution Approach 1:
The patent implements feedback by continuously monitoring the inductor current through sensing nodes and using this information to adjust the switching frequency. The PWM controller detects current ripple characteristics and automatically modifies operating parameters to maintain stable output voltage and current, eliminating the need for slow response mechanisms that would cause power loss
3Reliability
If the switching frequency is adjusted dynamically in response to current ripple range, then the effects of magnetic coupling are mitigated, but the device complexity increases due to additional sensing nodes and control logic
Solution Approach 1:
The patent applies universality by designing the PWM controller to perform multiple functions: it generates PWM signals for switching control, detects current ripple through sensing nodes, determines inductance variations, and adjusts switching frequency accordingly. This multi-functionality reduces the need for separate dedicated circuits for each function, thereby limiting the increase in overall device complexity while maintaining power converter stability
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 effectively reduces voltage drops and maintains average current levels by dynamically adjusting the switching frequency, thereby minimizing the impact of unexpected magnetic coupling on power converter performance.
Implementation Method 1
An output voltage provided by the DC/DC power converter is generated at the second end of the inductive element through the inductive element
Data Source
AI summary
A method of a DC-to-DC (DC/DC) power converter includes: providing the DC/DC power converter having a switching node and an output sensing node, the switching node is used to be coupled to a first end of an inductive element which is externally connected to the DC/DC power converter, the output sensing node is used to be coupled to a second end of the inductive element, and an output voltage provided by the DC/DC power converter is generated at the second end of the inductive element through the inductive element; and, adjusting a switching frequency employed by the DC-to-DC power converter in response to a specific event that a ripple range of a current flowing through the inductive element reaches or exceeds above a specific range, wherein the specific event is detected by the DC/DC power converter via the switching node and the output sensing node.