Band-Pass Filter Circuit Using Capacitance Ratios for Stable Q-Factor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing band pass filters in display devices face challenges in accurately setting parameters due to mismatches between resistors and capacitors, leading to fluctuations in Q-factor and gain, and often require multiple amplifiers for functionality.
Innovation Solution
A band pass filter design that determines parameters based on capacitance ratios, allowing for implementation with a single amplifier and minimizing mismatches between resistors and capacitors, utilizing integrators and high pass filter converters to achieve accurate filtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional band pass filter design using resistor and capacitor is used, then filtering function is achieved, but parameter accuracy deteriorates due to mismatch between resistor and capacitor
Solution Approach 1:
The patent changes the fundamental parameters of the filter design from using resistor-capacitor combinations to using only capacitors with different capacitance values. This parameter change eliminates the mismatch problem between different component types while maintaining the filtering function through capacitive reactance differences at specific frequencies.
Solution Approach 2:
The filter is segmented into multiple capacitor stages with different capacitance values, where each capacitor contributes to specific frequency filtering. This segmentation allows independent optimization of each capacitor's value to achieve precise overall filter parameters without relying on matched resistor-capacitor pairs.
2Adaptability or versatility
If multiple amplifiers are used to implement buffer and variable gain functions, then functionality is improved, but device complexity increases
Solution Approach 1:
The patent designs a single amplifier that performs multiple functions including buffering, variable gain control, and signal conditioning. This multi-functional amplifier replaces what would traditionally require separate dedicated amplifiers for each function, reducing overall device complexity while maintaining full functionality.
Solution Approach 2:
The patent merges the buffer function and variable gain function into a single amplifier stage, combining what were previously separate functional blocks. This merging reduces the total number of active components while achieving the same overall system functionality through integrated design.
3Reliability
If traditional filter design with multiple components is used, then filtering capability is achieved, but manufacturing precision requirements increase due to component matching
Solution Approach 1:
The patent changes the component basis from resistor-capacitor pairs to capacitor-only implementation, where capacitance ratios between components are easier to control with high precision during manufacturing. This parameter change reduces the stringency of matching requirements while maintaining reliable filtering performance.
Data Source
AI summary
A sensor device includes: first sensors; second sensors which form capacitances with the first sensors; a sensor transmitter connected to the first sensors, where the sensor transmitter supplies driving signals to the first sensors; and a sensor receiver connected to the second sensors, where the sensor receiver receives sensing signals from the second sensors, and the sensor receiver includes a band pass filter which filters the sensing signals. The band pass filter includes: a first integrator including a first amplifier; a first high pass filter converter connected to a first input terminal, a second input terminal and a first output terminal of the first amplifier, where the first high pass filter converter time-divisionally provides N high pass filter conversion paths; and a first gain auxiliary component connected to the first input terminal and the first output terminal of the first amplifier while the first integrator performs an integral function.