Single-Op-Amp Reconstruction Filter for Low-Power Multi-Mode RF
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Solution Overview
Problem
Traditional reconstruction filters in integrated circuits consume high power due to multiple stages of operational amplifiers, exhibit non-linear characteristics, and high noise levels, making them inefficient for multi-mode multi-band wireless transceivers.
Innovation Solution
A multi-mode reconstruction filter with a single transconductor (op-amp) and same-type device capacitors and resistors, configured for low power consumption and linear voltage-to-current conversion, using a mirror device for noise filtering and programmable resistor values to adapt to different communication standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple stages of filters with operational amplifiers are used, then filtering performance is improved, but power consumption increases
Solution Approach 1:
The patent merges multiple filter stages into a single transconductor-based filter circuit. Instead of using separate operational amplifier stages, the invention combines the filtering functionality into one integrated circuit block that achieves the same or better filtering performance with significantly reduced power consumption.
Solution Approach 2:
The patent replaces the traditional operational amplifier-based mechanical/electrical filter stages with a transconductor-based system. This substitution uses a different operational mechanism (transconductor current control) to achieve filtering, eliminating the need for multiple power-hungry operational amplifier stages.
2Ease of operation
If voltage to current conversion is performed in traditional filters, then signal processing is achieved, but non-linear characteristics are introduced
Solution Approach 1:
The patent changes the operating parameters and characteristics of the filter by using a transconductor with specific biasing and configuration. This parameter change enables the circuit to perform voltage-to-current conversion while maintaining linear characteristics through careful design of the transconductor operating point and feedback mechanisms.
3Reliability
If traditional reconstruction filter design is used, then basic filtering is achieved, but noise characteristics are high
Solution Approach 1:
The patent extracts and removes the noise-generating elements from the filter design. By eliminating multiple operational amplifier stages and their associated noise sources, the invention achieves low noise performance while maintaining the essential filtering function through the streamlined transconductor-based architecture.
Data Source
AI summary
A circuit (e.g., a reconstruction filtering circuit) may include a single operational amplifier (op-amp) that is arranged to receive a voltage input and that is arranged to have a biasing of constant gmR, a first device capacitor that is operatively coupled to an output of the single op-amp, a first resistor that is operatively coupled to the first device capacitor, a second device capacitor that is operatively coupled to the first resistor, and a mirror device that is operatively coupled to the second device capacitor, where the mirror device is arranged to provide a feedback loop as a feedback input to the single op-amp and that is arranged to provide a current output.