Feed-Forward Low-Pass Filtering for Noise Reduction in Smaller IC Area
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In integrated circuit design, RC low-pass filters require significant area due to resistor costs, necessitating a technique to reduce filter area while effectively filtering out noise.
Innovation Solution
A filtering device comprising a low-pass filter, noise estimation circuit, and combining circuit that subtracts estimated noise from the input signal, or a low-pass filter with a feedback circuit and resistor circuit to generate a pre-filtering signal, allowing for effective noise reduction without increasing resistor area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an RC low-pass filter is used to filter out undesired noise, then noise filtering performance is improved, but the area occupied by the filter increases due to resistor costs
Solution Approach 1:
The filtering function is segmented into two parts: a first low-pass filter that processes the input signal to generate a pre-filtering signal, and a second low-pass filter that processes the pre-filtering signal to generate the output signal. This segmentation allows each filter to use smaller resistors, reducing the total area while maintaining effective noise filtering performance through the combined filtering action of both stages.
Solution Approach 2:
A pre-filtering signal is introduced as an intermediary between the input signal and the final output signal. This pre-filtering signal serves as a intermediate processing stage that enables the system to achieve the desired noise filtering performance with reduced resistor values, thereby reducing the overall filter area occupation in the integrated circuit.
2Object-affected harmful factors
If resistor values are increased to improve noise filtering, then filtering performance is improved, but the area occupied by resistors increases
Solution Approach 1:
The filtering function is segmented into two parts: a first low-pass filter that processes the input signal to generate a pre-filtering signal, and a second low-pass filter that processes the pre-filtering signal to generate the output signal. This segmentation allows each filter to use smaller resistors, reducing the total area while maintaining effective noise filtering performance through the combined filtering action of both stages.
Solution Approach 2:
The system changes the parameter configuration by using multiple filter stages with smaller individual resistor values instead of a single stage with large resistor values. The first low-pass filter uses a first set of resistor values and the second low-pass filter uses a second set of resistor values, both smaller than what would be required in a single-stage filter, thereby reducing total resistor area while achieving the desired noise filtering performance.
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 and minimizes the area required for the low-pass filter in integrated circuits, addressing the challenge of resistor cost and space constraints.
Implementation Method 1
a low pass-filter (LPF) is arranged to receive and filter a pre-filtering signal to generate an output signal
Implementation Method 2
a noise estimation circuit is arranged to estimate an estimated noise signal according to the output signal and the pre-filtering signal
Implementation Method 3
a first combining circuit is arranged to subtract the estimated noise signal from an input signal of the filtering device to generate the pre-filtering signal
Data Source
AI summary
A filtering device includes a low-pass filter (LPF), a noise estimation circuit and a first combining circuit. The LPF receives and filters a pre-filtering signal to generate an output signal of the filtering device. The noise estimation circuit estimates an estimated noise signal according to the output signal and the pre-filtering signal. The first combining circuit subtracts the estimated noise signal from an input signal of the filtering device to generate the pre-filtering signal.