Dynamic Charge Redistribution Circuit for Stable Capacitance Testing
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Solution Overview
Problem
Existing capacitance testing methods struggle with stability when large differences in capacitance values result in small charge movement and voltage changes, leading to unreliable testing.
Innovation Solution
A circuit device with a control circuit that dynamically couples and decouples capacitance elements with operational amplifiers to apply and redistribute charges, using comparison circuits to accurately test capacitance values by adjusting voltages and parasitic capacitances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If different voltages are applied to tested and test capacitance elements and they are electrically coupled to test capacitance based on charge movement, then capacitance value can be tested, but when the difference between capacitance values is large, charge movement becomes small and voltage change is small making testing unstable
Solution Approach 1:
The patent applies dynamics by making the capacitance element configuration changeable during testing. The control circuit dynamically switches between different capacitance element connections (tested capacitance element connected to test capacitance element, or tested capacitance element connected to reference capacitance element) based on the capacitance value range being tested. This dynamic reconfiguration ensures optimal charge movement and voltage change for each testing scenario, resolving the stability issue when capacitance values differ significantly.
Solution Approach 2:
The patent changes the capacitance parameters by introducing both test capacitance elements and reference capacitance elements with different known capacitance values. The control circuit selects appropriate reference capacitance elements based on the expected capacitance range of the tested element. This parameter variation allows the system to maintain sufficient voltage change and charge movement across different capacitance testing scenarios, improving both accuracy and stability.
2Device complexity
If a single test capacitance element is used, then the circuit structure remains simple, but it cannot provide sufficient voltage change when testing capacitance elements with large capacitance differences
Solution Approach 1:
The patent segments the capacitance element resource into multiple test capacitance elements and reference capacitance elements with different capacitance values. Instead of using a single test capacitance element, the system divides the capacitance testing function across multiple elements, each optimized for specific capacitance ranges. This segmentation enables sufficient voltage change for different capacitance scenarios while keeping each individual element simple.
Solution Approach 2:
The patent makes the capacitance elements serve multiple functions: test capacitance elements are used for actual capacitance measurement, while reference capacitance elements provide known capacitance values for comparison. The same basic circuit structure handles both testing and reference functions by dynamically reconfiguring connections through the control circuit, achieving multi-functionality without proportionally increasing complexity.
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 method enhances testing accuracy by ensuring sufficient charge movement and voltage fluctuations, enabling reliable testing of capacitance elements with varying values.
Implementation Method 1
move a charge of the first tested capacitance element and set the second end to a first test voltage
Data Source
AI summary
A control circuit couples a test capacitance element Cp and a node Test to a capacitance element Cm1-1 to be tested, and applies a voltage output from an operational amplifier circuit to the capacitance elements Cm1-1 and Cp and the node Test. Thereafter, the capacitance element Cp and the node Test are decoupled from the capacitance element Cm1-1 to be tested, the capacitance element and the node Test are coupled to the capacitance element Cm1-1, the charge accumulated in the capacitance element Cm1-1 is moved, a voltage Vref of a negative input-end (−) of a comparison circuit is set, and the capacitance element Cm1-1 is tested based on a signal output from the comparison circuit.