MLCC Energy Calculation Using Usage Condition-Aware Capacitance
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Solution Overview
Problem
Existing capacitor energy calculation methods assume constant capacitance, leading to inaccuracies in energy calculations for multi-layer ceramic capacitors (MLCCs) used in backup power supplies, resulting in an overestimation of required MLCCs and hindering the reduction of the backup power supply's profile due to a limited footprint.
Innovation Solution
A circuit design apparatus and method that considers usage conditions to calculate the energy of capacitors, taking into account the varying capacitance of MLCCs, by storing first capacitance data and using a controller to calculate second capacitance based on specified usage conditions, allowing for accurate energy calculations and reducing the required number of capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the related art capacitor energy amount calculation method (equation 1) is used, then the calculation is simple, but the calculated energy amount is inaccurate when capacitance varies with usage conditions
Solution Approach 1:
The patent changes the parameter approach by storing multiple capacitance values corresponding to different usage conditions (voltages, temperatures, time periods) and selecting the appropriate capacitance value based on the specific usage condition. This resolves the contradiction by making the calculation accurate without requiring complex real-time measurements, as the capacitance variations are pre-characterized and stored in lookup tables.
Solution Approach 2:
The patent performs preliminary characterization of capacitance variations under different usage conditions and stores the results in advance. During energy calculation, the pre-stored capacitance values are directly used without requiring complex real-time analysis. This preliminary action resolves the contradiction by preparing accurate capacitance data beforehand, enabling precise energy calculation with simple lookup operations.
2Use of energy by moving object
If the number of MLCCs is increased to ensure sufficient energy storage, then the energy storage capability is improved, but the footprint and profile of the backup power supply increase
Solution Approach 1:
The patent replaces the mechanical approach of simply increasing capacitor quantity with a computational approach that uses usage condition-aware energy calculation. By accurately calculating the actual energy storage capability considering capacitance variations, the system determines the minimum number of MLCCs needed, eliminating the need to over-provision and thus reducing the footprint while maintaining sufficient energy storage.
Solution Approach 2:
The patent changes the calculation parameters from assuming constant minimum capacitance to using variable capacitance values that reflect actual usage conditions. This results in more accurate energy calculations that show fewer capacitors are needed than previously calculated, thereby reducing the required footprint while maintaining the required energy storage capability.
3Adaptability or versatility
If MLCCs are used to achieve profile reduction, then the adaptability to size reduction is improved, but the capacitance variation with usage conditions causes calculation inaccuracy
Solution Approach 1:
The patent addresses the capacitance variation issue by changing from a single constant capacitance parameter to multiple capacitance parameters corresponding to different usage conditions (voltages, temperatures, time periods). The system selects the appropriate capacitance value based on the specific usage condition, thereby maintaining calculation accuracy while preserving the ability to use MLCCs for profile reduction.
Solution Approach 2:
The patent introduces feedback by using the calculated energy amount to iteratively determine the number of capacitors needed. The calculation process incorporates usage condition information to refine the capacitance value selection, ensuring accurate energy calculation that reflects the actual performance of MLCCs under specific operating conditions, thereby enabling precise footprint optimization.
Data Source
AI summary
A circuit design apparatus includes a storage that stores a first capacitance of a capacitor associated with one or more usage conditions, and a controller that controls an amount of energy of the capacitor under a specified usage condition of the one or more usage conditions. The controller calculates a second capacitance under the specified usage condition based on a first relationship between the specified usage condition and the first capacitance, and calculates the amount of energy of the capacitor based on the calculated second capacitance.