Nonlinear Inductor Series Cores Light-Load Efficiency
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Solution Overview
Problem
Switched-mode power supplies for portable electronic devices face tradeoffs between size, efficiency, and transient response, particularly at light loads and during transient events, due to the size and material limitations of inductors, which affect their overall performance.
Innovation Solution
A power supply using a nonlinear inductor with two cores of different materials connected in series, where the second core has higher permeability and lacks an air gap, allowing for high inductance at low currents and low inductance at high currents, enabling improved light-load efficiency and transient response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the inductance of the inductor is increased to improve light-load efficiency, then light-load efficiency is improved, but transient response deteriorates
Solution Approach 1:
The inductor uses a nonlinear magnetic core that dynamically changes its inductance value based on the operating conditions. At light loads, the core operates in a high-permeability region providing high inductance for efficiency. During transient events, the core saturation characteristics cause inductance to decrease, enabling faster response. This dynamic adaptation resolves the contradiction between light-load efficiency and transient response.
Solution Approach 2:
The patent changes the magnetic permeability parameter of the core material to achieve different inductance values. By selecting a core material with nonlinear B-H characteristics, the inductor provides high inductance at low current (light load) and lower inductance at high current (transient conditions), thereby improving both light-load efficiency and transient response through parameter variation.
2Speed
If the inductance of the inductor is decreased to improve transient response, then transient response is improved, but light-load efficiency deteriorates
Solution Approach 1:
The nonlinear core enables the inductor to automatically adjust its inductance based on operating conditions. During transient events requiring fast response, the core saturation effect reduces inductance to enable quicker current changes. During light-load operation, the core operates in the linear high-permeability region maintaining high inductance for efficiency, thus resolving the tradeoff.
Solution Approach 2:
The magnetic core's permeability parameter changes with the operating point. At high current during transients, the core approaches saturation reducing effective permeability and inductance for faster response. At light loads, the core operates at low flux density with high permeability maintaining high inductance for efficiency, achieving both performance requirements through parameter variation.
3Loss of energy
If larger inductors are used to improve efficiency, then efficiency is improved, but size and cost increase
Solution Approach 1:
The patent utilizes the nonlinear magnetic characteristics of the core material to achieve variable inductance. A single inductor design provides high inductance at light loads for efficiency while maintaining a compact size suitable for portable devices. The nonlinear core allows the inductor to adapt its effective inductance value rather than requiring multiple inductors of different sizes.
Solution Approach 2:
The nonlinear inductor performs multiple functions with a single component: it provides high inductance for light-load efficiency and lower inductance for transient response capability. This multi-functionality eliminates the need for separate inductors optimized for different operating conditions, reducing overall size and component count while maintaining efficiency.
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 configuration enhances both light-load efficiency and transient response by adjusting inductance based on load conditions, optimizing power supply performance in portable devices.
Implementation Method 1
the second core has a higher permeability than the first core
Implementation Method 2
A nonlinear inductor includes a first core and a second core connected in series to the first core
Data Source
AI summary
The disclosed embodiments relate to a power supply for a portable electronic device. The power supply includes a power source and a nonlinear inductor. The nonlinear inductor includes a first core and a second core connected in series to the first core, wherein the second core has a higher permeability than the first core.