Switched Resistor Discharge Circuit for Capacitive Noise Control
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Solution Overview
Problem
Existing noise reduction strategies for capacitive sensor devices face challenges in balancing noise emission reduction with noise immunity, as low impedance circuits effectively reduce noise emission but compromise noise resistance, while high impedance circuits improve noise resistance but hinder device operation under noise conditions.
Innovation Solution
A noise reduction unit with multiple resistors of different values in parallel, connected via a resistor switch that switches between high and low impedance states during charging and discharging, allowing efficient charge management and improved immunity during operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a low impedance circuit is used to reduce noise emission, then noise emission is reduced, but noise immunity deteriorates
Solution Approach 1:
The patent applies dynamics by making the impedance of the discharge circuit variable rather than fixed. The resistor switch dynamically changes the resistance value during the discharge process, transitioning from a high impedance state (first resistor) to a low impedance state (second resistor). This dynamic adjustment allows the system to optimize both noise emission reduction and noise immunity at different stages of the discharge process.
Solution Approach 2:
The patent applies preliminary action by first connecting the first resistor (high impedance) to the capacitor before the discharge process begins. This preliminary high impedance connection suppresses noise emission during the initial discharge phase. After a predetermined time has elapsed, the switch then connects the second resistor (low impedance) to maintain noise immunity while the discharge continues.
2Reliability
If a high impedance circuit is used to improve noise immunity, then noise immunity is improved, but noise emission increases
Solution Approach 1:
The patent applies dynamics by making the impedance of the discharge circuit variable rather than fixed. The resistor switch dynamically changes the resistance value during the discharge process, transitioning from a high impedance state (first resistor) to a low impedance state (second resistor). This dynamic adjustment allows the system to optimize both noise emission reduction and noise immunity at different stages of the discharge process.
Solution Approach 2:
The patent applies preliminary action by first connecting the first resistor (high impedance) to the capacitor before the discharge process begins. This preliminary high impedance connection suppresses noise emission during the initial discharge phase. After a predetermined time has elapsed, the switch then connects the second resistor (low impedance) to maintain noise immunity while the discharge continues.
3Device complexity
If a single resistor is used for discharge, then device complexity is reduced, but the ability to balance noise emission and immunity is compromised
Solution Approach 1:
The patent applies segmentation by dividing the discharge circuit into multiple segments with different resistance values. Instead of using a single resistor, the circuit is segmented into at least two resistors (first resistor with higher resistance, second resistor with lower resistance) that can be selectively connected. This segmentation allows the system to adapt to different discharge stages and optimize both noise emission reduction and noise immunity.
Solution Approach 2:
The patent applies dynamics by making the impedance of the discharge circuit variable rather than fixed. The resistor switch dynamically changes the resistance value during the discharge process, transitioning from a high impedance state (first resistor) to a low impedance state (second resistor). This dynamic adjustment allows the system to optimize both noise emission reduction and noise immunity at different stages of the discharge process.
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 solution effectively reduces noise emission during discharge while maintaining improved noise immunity by managing current flow and voltage changes, ensuring stable device operation.
Implementation Method 1
a capacitor is charged so that change in its electrostatic capacitance is detectable
Implementation Method 2
The plurality of resistors have different resistance values. When the device is discharged, the resistor switch first connects a first resistor of the plurality of resistors to the device and then connects a second resistor of the plurality of resistors to the device.
Data Source
AI summary
A noise reduction unit includes a plurality of resistors arranged in parallel in a line connected to a device that is charged and discharged and having different resistance values. The noise reduction unit further includes a resistor switch that switches a resistor connected to the device between the plurality of resistors. When the device is discharged, the resistor switch first connects a first one of the plurality of resistors to the device and then connects a second one of the plurality of resistors to the device. The first resistor has a larger resistance value than the second resistor.