Area Efficient Baseband Filter Using Transistor Feedback
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Solution Overview
Problem
Conventional baseband filters in wireless devices require significant circuit area to achieve desired signal-to-noise ratio (SNR) performance, limiting their efficiency and linearity.
Innovation Solution
A novel baseband filter configuration that eliminates the DC current sink circuit and utilizes transistors for both feedback and biasing, reducing the number of noise elements and circuit area while maintaining improved linearity and noise performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional baseband filter configuration with DC current sink circuit is used, then noise performance is maintained, but circuit area increases and linearity deteriorates
Solution Approach 1:
The patent removes the DC current sink circuit from the conventional baseband filter configuration. By extracting this component, the circuit area is reduced while the noise performance is maintained through alternative biasing arrangements using transistors for both feedback and biasing functions.
Solution Approach 2:
The patent combines multiple functions into the transistor-based feedback configuration. Transistors serve dual purposes as both feedback elements and biasing circuits, eliminating the need for separate DC current sink circuits and reducing overall circuit area while maintaining performance.
2Reliability
If conventional baseband filter configuration with DC current sink circuit is used, then noise performance is maintained, but linearity deteriorates
Solution Approach 1:
By removing the DC current sink circuit, the patent eliminates a source of non-linearity in the conventional filter configuration. The alternative transistor-based biasing arrangement provides improved linearity while maintaining noise performance through careful circuit design.
Solution Approach 2:
The patent changes the operating parameters and configuration of the feedback circuit using transistors. By adjusting the biasing conditions and feedback mechanisms, the circuit achieves both improved linearity and maintained noise performance simultaneously.
3Reliability
If more passive elements and amplifier area are used, then desired SNR performance is achieved, but circuit area increases
Solution Approach 1:
The patent makes the transistors in the feedback configuration perform multiple functions simultaneously - serving as both feedback elements and biasing circuits. This multi-functionality reduces the need for separate components, thereby reducing circuit area while maintaining SNR performance.
Solution Approach 2:
The patent optimizes the parameters of the transistor-based feedback circuit to achieve desired SNR performance with reduced component count. By carefully selecting transistor dimensions, biasing conditions, and feedback ratios, the circuit achieves target performance with minimal circuit area.
Data Source
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AI summary
An area efficient baseband filter is disclosed. In an exemplary embodiment, an apparatus includes a current to voltage (l-V) filter (300) configured to receive an input current signal at an input port (310) and generate a filtered output voltage signal at an output port (312) based on a feedback transconductance. The input current signal comprises an input DC current in addition to a signal current. The apparatus also includes a feedback circuit (308) connected between the output port (312) and the input port (310), the feedback circuit having at least one transistor (T1a-d) configured to couple the input DC current to a signal ground and to provide the feedback transconductance for the l-V filter (300).