Integrated AC Voltage Divider Capacitors for Precision Matching
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Solution Overview
Problem
AC voltage dividers using discrete Multilayer Ceramic Capacitors (MLCC) face challenges in achieving precise capacitance matching, are prone to thermal issues, and risk sparks/short-circuits due to derating, especially in high voltage applications where space and thermal constraints are critical.
Innovation Solution
The solution involves integrating multiple capacitors within a single component on a semiconductor substrate, using parallel manufacturing techniques to ensure identical electrical parameters, thereby stabilizing the dividing ratio and reducing individual capacitance tolerance requirements, and employing 3D capacitors with shared electrodes to enhance reliability and prevent sparks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If discrete MLCC capacitors are used in voltage divider, then high capacitance values can be achieved, but precise capacitance matching (2% or 1% tolerance) is difficult to achieve and requires preliminary sorting
Solution Approach 1:
The patent merges multiple capacitors into a single integrated component where capacitors are formed on the same substrate using the same manufacturing process. This ensures they have identical or closely matched electrical parameters without requiring separate sorting operations, directly resolving the contradiction between achieving precise capacitance matching and avoiding complex sorting procedures
Solution Approach 2:
The capacitors are pre-matched during the manufacturing process itself by forming them simultaneously on the same substrate with identical materials and processes. This preliminary action of matching during fabrication eliminates the need for post-manufacturing sorting, resolving the contradiction between precision requirements and sorting complexity
2Quantity of substance
If MLCC components of size 3.2mm by 1.6mm are used, then high capacitance values can be achieved, but integration and compactness are compromised especially in high voltage applications with limited space
Solution Approach 1:
Multiple capacitor elements are merged into a single integrated component structure where they share common electrodes and substrate space. This allows achieving the required total capacitance value while occupying significantly less board space than discrete MLCC components, resolving the contradiction between capacitance value and component size
Solution Approach 2:
The patent employs 3D capacitor structures with vertical electrode arrangements and multi-layer configurations. By utilizing the vertical dimension and stacking layers, high capacitance values are achieved within a compact footprint, resolving the contradiction between capacitance magnitude and horizontal space occupation
3Area of stationary object
If MLCC components are located close to inverters in high voltage applications, then space constraints are addressed, but thermal constraints become critical and risks of sparks/short-circuits increase due to derating
Solution Approach 1:
Capacitors of the same dividing stage are merged into a single integrated component with shared electrodes and substrate. This ensures uniform thermal response to temperature changes, stabilizing the dividing ratio and preventing derating issues that could lead to sparks or short-circuits, thus resolving the contradiction between space utilization and reliability
Solution Approach 2:
The integrated component design changes the thermal parameter response by ensuring all capacitors experience identical temperature variations. This parameter uniformity prevents differential derating effects that could cause voltage instability and spark risks, resolving the contradiction between compact placement and safety reliability
Data Source
Figure 1~2
Figure 3A~3B
Figure 4
AI summary
An electrical device comprising an AC voltage divider comprising a board (BRD), a plurality of dividing stages each associated with a dividing ratio (Q), an input terminal (301) arranged on the board for receiving an input voltage, and an output terminal (302) arranged on the board for outputting a divided voltage, wherein each dividing stage comprises a plurality of capacitors, and for each dividing stage, the plurality of capacitors of this dividing stage is arranged in a same integrated component (200A, 200B, 200C) assembled on the board and electrically connected between the input terminal and the output terminal. The invention also concerns the corresponding manufacturing method.