Averaging Mixer-Op-Amp RF Front-End for Low-Noise Gain
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing RF receiver front-ends face challenges with high power dissipation, noise, linearity, and sensitivity, particularly in low power applications where passive mixers require additional gain, and are limited by silicon area and noise performance.
Innovation Solution
An electric circuit for RF receiver front-ends incorporating an averaging mixer with I and Q paths, each comprising a switch, input capacitor, operational amplifier, feedback capacitor, and a bias resistor, which provides simultaneous mixing and gaining functions by averaging incoming signals, reducing the need for large gain further down the receiver chain and minimizing noise and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If passive mixers are used, then noise performance and linearity are improved, but power gain is lost requiring additional amplification
Solution Approach 1:
The patent combines the mixing function and amplification function into a single integrated circuit block. The operational amplifier simultaneously performs signal mixing through the capacitor network and provides power gain through its amplification action, eliminating the need for separate passive mixer and amplifier stages.
Solution Approach 2:
The operational amplifier is designed to perform multiple functions: it acts as both a mixing element (through its interaction with the capacitor network and switching devices) and a power amplifying element. This multi-functional design resolves the contradiction by providing both low noise performance and sufficient power gain within a single device.
2Power
If active mixers are used, then power gain is provided, but linearity and noise performance deteriorate
Solution Approach 1:
The patent merges the mixing and amplification functions in a way that the operational amplifier provides controlled gain only when needed for low-power applications, while maintaining good linearity through its high-input impedance characteristics and the passive nature of the mixing network.
3Power
If additional amplification stages are added, then power gain is increased, but silicon area and power dissipation increase
Solution Approach 1:
The patent eliminates the need for separate amplification stages by integrating the amplification function directly into the mixing circuitry. The operational amplifier provides the necessary gain within the same circuit block that performs mixing, significantly reducing the total silicon area required.
Solution Approach 2:
The operational amplifier serves as a universal element that simultaneously provides mixing and amplification functions, replacing what would traditionally require multiple specialized components. This multi-functionality reduces both silicon area and power dissipation while maintaining the required power gain.
4Device complexity
If mixing and amplification are separated, then circuit simplicity is maintained, but power dissipation and device complexity increase
Solution Approach 1:
The patent combines mixing and amplification into a single integrated circuit block, reducing the total number of discrete components and interconnections. This integration simplifies the overall circuit architecture while reducing power dissipation by eliminating the need for multiple independent power supply networks and reducing the total component count.
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 achieves low noise, high linearity, and reduced power dissipation while optimizing silicon area, making it suitable for low power applications and improving overall RF receiver performance.
Implementation Method 1
the operational amplifier so that an amplified down-converted signal appears at the output of the operational amplifier
Data Source
AI summary
An electric circuit providing mixing and gaining functions for a RF receiver front-end, including an I path and a Q path. Each of the I path and Q path includes: a switch, an input capacitor between the switch and an input of an operational amplifier, and a feedback capacitor between the input and the output of the operational amplifier. The electric circuit includes: a local oscillator arranged to generate a carrier signal having a carrier frequency, a command module arranged to sequentially close each switch during a mixer's averaging window, so that an incoming signal having a frequency close to the carrier frequency results in a non-zero down-converted signal across the input capacitor. This down-converted signal is amplified by the operational amplifier so that an amplified down-converted signal appears at the output of the operational amplifier. A RF front-end is inductor-less, includes a linearity optimized LNA, and/or has reconfigurable topology.