Multilayer Ceramic Capacitor Vise Structure for Acoustic Noise Reduction
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Solution Overview
Problem
Multilayer ceramic capacitors in high-frequency circuits generate acoustic noise due to piezoelectric properties, which are amplified by the circuit board and casing, and reducing the dielectric constant to mitigate noise results in lower capacitance and larger size.
Innovation Solution
A monolithic capacitor structure with a main capacitor and a 'vise' capacitor that provides a clamping effect to counteract piezoelectric deformations, using electrical circuitry with voltage difference and delay elements to produce compensating signals that are inversely proportional to the main capacitor's signals, effectively reducing or eliminating noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the dielectric constant of the ceramic material is reduced to mitigate acoustic noise, then the acoustic noise level decreases, but the capacitance value decreases and/or the capacitor size increases
Solution Approach 1:
The capacitor is divided into two separate capacitor elements with different dielectric materials, each optimized for different functions: one for high capacitance and one for low noise performance, allowing both requirements to be met simultaneously without compromise
Solution Approach 2:
Different regions of the capacitor structure use different dielectric materials with locally optimized properties - the first capacitor element uses material optimized for capacitance while the second uses material optimized for low piezoelectric effect, allowing each local region to perform its specific function optimally
2Object-affected harmful factors
If the dielectric constant of the ceramic material is reduced to mitigate acoustic noise, then the acoustic noise level decreases, but the capacitor size increases
Solution Approach 1:
The capacitor is divided into two separate capacitor elements with different dielectric materials, each optimized for different functions: one for high capacitance and one for low noise performance, allowing both requirements to be met simultaneously without compromise
Solution Approach 2:
Different regions of the capacitor structure use different dielectric materials with locally optimized properties - the first capacitor element uses material optimized for capacitance while the second uses material optimized for low piezoelectric effect, allowing each local region to perform its specific function optimally
3Volume of moving object
If a single capacitor element is used to maintain compact size and high capacitance, then the capacitor dimensions are reduced, but acoustic noise is generated due to piezoelectric effects
Solution Approach 1:
The capacitor is divided into two separate capacitor elements with different dielectric materials, each optimized for different functions: one for high capacitance and one for low noise performance, allowing both requirements to be met simultaneously without compromise
Solution Approach 2:
The capacitor uses a composite structure combining two different dielectric materials with complementary properties, creating a multi-material system that achieves both high capacitance and low acoustic noise through the synergistic combination of different material characteristics
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 significantly reduces acoustic noise by compensating for piezoelectric-induced vibrations, maintaining capacitance and compact size while rendering noise inaudible by doubling the frequency of vibrations outside the hearing range.
Implementation Method 1
The materials forming the dielectric in multilayer ceramic capacitors may have a piezo-electric nature, i.e., changes in applied voltage may result in changes to the physical dimension of the capacitor. The vise capacitor is arranged to provide piezoelectric deformation that is inversely proportional to that caused by the main capacitor
Implementation Method 2
The circuits may include delay elements that allow a phase shift between the electrical signals received by the main and the vise capacitor, which may double the frequency of vibration and render the associated acoustic noise inaudible
Data Source
AI summary
Monolithic capacitor structures having a main capacitor and a vise capacitor are discussed. The vise capacitor provides to the monolithic capacitor structure reduced vibrations and/or acoustic noise due to piezoelectric effects. To that end, vise capacitor may cause piezoelectric deformations that compensate the deformations that are caused by the electrical signals in the main capacitor. Embodiments of these capacitor structures may have the main capacitor and the vise capacitor sharing portions of a rigid dielectric. Electrical circuitry that employs the vise capacitor to reduce noise and/or vibration in the monolithic capacitor structures is also described. Methods for fabrication of these capacitors are discussed as well.