Integral Value Measuring Circuit With Cross Resistance Elements
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Solution Overview
Problem
Existing integral value measuring circuits face challenges in accurately measuring integral values due to the influence of leakage resistance and parasitic capacitance when switches change states, leading to noise currents and complex equations.
Innovation Solution
An integral value measuring circuit is designed with operational amplifiers and capacitors, where the output terminal is set to zero using a resistance element, and switches are connected between the power terminals and DC voltage generating circuits, with cross resistance elements that do not contact each other, eliminating the impact of leakage resistance and parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a switch is provided in parallel between both electrode sides of the capacitor to control charging, then the integral state can be formed, but leakage resistance and parasitic capacitance cause noise current and measurement inaccuracy
Solution Approach 1:
The patent extracts the switch from the capacitor parallel connection and relocates it to the power supply lines. This removes the switch's harmful effects (leakage resistance and parasitic capacitance) from the measurement circuit while preserving its control function for capacitor charging and discharging.
Solution Approach 2:
The patent introduces cross resistance elements as intermediaries between the power supply lines and the operational amplifier. These resistance elements isolate the power supply switching operations from the measurement circuit, preventing noise current from affecting the integral value measurement.
2Ease of repair
If the switch changes from ON to OFF state to discharge the capacitor, then the reset function is achieved, but leakage resistance and parasitic capacitance generate noise current
Solution Approach 1:
The patent extracts the switch from the capacitor discharge path and relocates it to the power supply lines. This removes the source of noise current generation during reset operations while maintaining the ability to discharge the capacitor through power supply isolation.
Solution Approach 2:
The patent converts the switch's inherent leakage and parasitic effects from harmful factors into isolated power supply disturbances. By placing switches on power lines rather than signal lines, the harmful effects are confined to the power supply domain and prevented from coupling into the measurement circuit.
3Device complexity
If the switch is connected directly to the capacitor to enable charging control, then the circuit structure is simple, but leakage resistance and parasitic capacitance complicate the integral equation
Solution Approach 1:
The patent extracts the switch from the direct capacitor connection and relocates it to the power supply lines. This maintains relatively simple circuit structure while eliminating the mathematical complications caused by switch-induced leakage and parasitic capacitance in the integral equation.
Solution Approach 2:
The patent segments the circuit into a measurement section (capacitor and operational amplifier) and a control section (power supply and switches). This segmentation isolates the mathematical model of the measurement section from the switching operations, preserving the simplicity of the integral equation.
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 configuration allows for accurate measurement of integral values by isolating the effects of leakage resistance and parasitic capacitance, enabling precise integration of input voltages without noise currents, and facilitating a reset state by discharging the capacitor.
Implementation Method 1
a capacitor connected between an input side and an output side of the operational amplifier
Implementation Method 2
an operational amplifier and a capacitor connected between an input side and an output side of the operational amplifier
Data Source
AI summary
An integral value measuring circuit includes an operational amplifier and a capacitor connected between input and output sides thereof, an electric potential of an output terminal where a predetermined resistance element connected to an output side of the operational amplifier is being zero, positive and negative DC voltage generating circuits which comprise positive and negative power sources, respectively, at the output side of the operational amplifier, the positive and negative DC voltage generating circuits and being connected to positive and negative power terminals, respectively, of the operational amplifier through switches, and a connection line between the negative power terminal and one switch and a connection line between the positive power terminal and another switch being connected to the positive and negative power terminals, respectively, of the operational amplifier through cross resistance elements having resistance values negligible compared to a leakage resistance value of the switches.