Matched Ceramic Capacitor Structures for Stability
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Solution Overview
Problem
High capacitance-density ceramic capacitors, such as class 2 multilayer ceramic capacitors (MLCCs), suffer from instability and accuracy issues due to temperature changes and voltage derating, leading to performance variability in electronic circuits that rely on matched capacitors.
Innovation Solution
The use of monolithic capacitor structures with interweaved electrode stacks and shielding layers to correlate variations between matched capacitors, reducing parasitic capacitance and enhancing stability, while maintaining high capacitance density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high capacitance density ceramic materials are used, then capacitance density is improved, but accuracy and stability deteriorate
Solution Approach 1:
The capacitor is divided into multiple individual capacitor elements (first capacitor element, second capacitor element, etc.) that are formed within a single monolithic ceramic body. Each capacitor element has its own electrode pairs and dielectric layers, allowing them to function as separate capacitors while being integrated in one component. This segmentation enables the use of high capacitance density materials while maintaining accuracy through correlated variations.
Solution Approach 2:
Multiple capacitor elements are merged into a single monolithic ceramic body, sharing common external electrodes and internal structure. The capacitor elements are formed using the same ceramic material and manufacturing process, ensuring they experience correlated variations in capacitance due to temperature, voltage, and other environmental factors. This merging provides both high capacitance density and improved matching accuracy.
2Measurement precision
If multiple separate capacitors are used to achieve matching, then accuracy is improved, but device size increases
Solution Approach 1:
Multiple capacitor elements that would traditionally be separate discrete components are merged into a single monolithic ceramic body. The capacitor elements share common external electrodes and are formed from the same ceramic material, reducing the overall device size while maintaining capacitor matching accuracy through correlated variations.
Solution Approach 2:
Multiple capacitor elements are nested within a single ceramic body, with each capacitor element containing its own electrode pairs and dielectric layers. The capacitor elements are arranged in a compact configuration sharing common structural elements, allowing multiple capacitors to be integrated in a space smaller than the sum of individual capacitor sizes.
3Quantity of substance
If class 2 ceramic materials are used, then capacitance density is improved, but voltage derating and piezoelectric vibrations occur
Solution Approach 1:
The capacitor is segmented into multiple capacitor elements formed from class 2 ceramic material. By dividing the total capacitance into multiple smaller capacitor elements, the voltage derating effect is reduced since each individual capacitor element experiences lower voltage stress. The segmentation also helps mitigate piezoelectric vibrations by distributing mechanical stress across multiple smaller elements rather than concentrating it in a single large capacitor.
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 approach results in more accurate and stable capacitor performance, enabling compact electronic devices with improved reliability and reduced variability, even under temperature and voltage changes.
Implementation Method 1
capacitor structures having pairs of matched capacitors
Implementation Method 2
high capacitance density due to using dielectric with particularly high permittivity
Implementation Method 3
may suffer piezoelectric vibrations
Data Source
AI summary
Capacitor devices having multiple capacitors with similar nominal capacitances are described. The capacitors may be multilayer ceramic capacitors (MLCCs) and may be fabricated employing class 2 materials. The arrangement of the electrodes in the device may reduce relative variations between the capacitors of the device. The capacitor devices may be allow high performance and compact electrical circuits that may employ matched capacitors.