Miniaturized Coil Component Self Resonant Frequency Control
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Solution Overview
Problem
The challenge is to develop a small coil component that can simultaneously function as a power inductor and a bead in the output terminal of an envelope tracker integrated circuit, while maintaining a self resonant frequency in a relatively low frequency region without altering the type of magnetic material or internal electrode shape, due to the miniaturization of electronic products.
Innovation Solution
A coil component with a body volume of 2.4 mm3 or less, featuring first and second external electrodes on opposing surfaces, where the product of inductance Ls and S/l is controlled within a specific range (0.45 μH·mm to 0.75 μH·mm) to adjust the self resonant frequency, allowing for integrated functions of a power inductor and a bead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the coil component is miniaturized to reduce volume, then the self resonant frequency shifts to excessively high frequency region, but the requirement is to maintain self resonant frequency in a relatively low frequency region (95 to 105 MHz) for noise blocking functionality
Solution Approach 1:
The patent adjusts the product of inductance Ls and the ratio S/l (where S is the area of external electrode regions on opposing surfaces and l is the minimum spaced distance between them) to a specific range of 0.45 μH·mm to 0.75 μH·mm. This parameter optimization allows the self resonant frequency to be positioned in the 95 to 105 MHz range while maintaining a compact coil component volume of 2.4 mm³ or less, thereby resolving the contradiction between miniaturization and frequency positioning reliability
Solution Approach 2:
The patent utilizes the three-dimensional space by forming external electrodes on opposing surfaces of the coil component body with specific area S and spacing l. This spatial arrangement in multiple dimensions allows optimization of the S/l ratio to control self resonant frequency without increasing the overall volume, effectively decoupling the volume constraint from the frequency positioning requirement
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
The solution effectively positions the self resonant frequency in a low frequency region (about 95 to 105 MHz), enabling the coil component to block band noise and provide high impedance, suitable for applications in power inductors within envelope tracker integrated circuits.
Implementation Method 1
a power inductor and a bead, in addition to a multilayer ceramic capacitor, have been used so as to prevent high-frequency noise (50 MHz or more, for example, 80 to 130 MHz) from being transferred to the power amplifier
Implementation Method 2
it has been difficult to implement a coil component as described above without changing a type of magnetic material or a shape of electrodes
Data Source
AI summary
A coil component includes a body having a volume of 2.4 mm3 or less and including at least one coil member embedded therein, and first and second external electrodes partially or entirely formed on first and second surfaces of the body opposing each other, respectively, wherein the product of inductance Ls (μH) and S/l (mm) is 0.45 (μH·mm) or more to 0.75 (μH·mm) or less in which S (mm2) is an area of regions of the first and second external electrodes disposed on the first and second surfaces of the body, and 1 (mm) is a minimum spaced distance between the first and second external electrodes formed on the first and second surfaces of the body.