Receiver Front-End Circuit for Parasitic Capacitance Tuning
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Solution Overview
Problem
Existing receiver front end modules face challenges in decoupling from antennas during non-receiving states, leading to undesirable parasitic capacitance and noise issues due to switch configurations, which affect signal transmission and reception.
Innovation Solution
A circuit design incorporating a first inductor magnetically coupled with a second inductor, forming a transformer, is used to tune out parasitic capacitance at the input terminal, while also providing electrostatic discharge protection and low noise amplification, by reducing the effective inductance and introducing a cascode arrangement of transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a switch is used to decouple the receiver front end module from the antenna during non-receiving states, then the receiver can be protected, but parasitic capacitance is introduced which degrades signal transmission
Solution Approach 1:
The patent extracts the harmful parasitic capacitance effect by introducing a tuning inductor that resonates with and cancels the switch capacitance. The inductor is connected to the input terminal and forms an LC resonant circuit with the switch capacitance, effectively removing the harmful capacitive effect at the operating frequency while maintaining the switch's protection function.
Solution Approach 2:
The tuning inductor acts as an intermediary element between the switch and the amplifier input. It mediates the conflict by providing a reactive component that counteracts the switch capacitance, allowing the switch to remain in the signal path without introducing harmful parasitic effects. The inductor transforms the capacitive loading into a resonant condition that eliminates the harmful effect.
2Object-generated harmful factors
If the effective inductance is reduced through magnetic coupling, then parasitic capacitance can be tuned out, but the inductor complexity increases
Solution Approach 1:
The patent combines multiple inductors with different inductance values into a magnetically coupled configuration. The first inductor with higher inductance and the second inductor with lower inductance are positioned to provide magnetic coupling, creating an effective inductance that is lower than either individual inductor. This merging approach achieves the desired effective inductance value while using standard inductor components.
Solution Approach 2:
The magnetically coupled inductor configuration serves multiple functions simultaneously: it provides the tuning inductance to cancel switch capacitance, it offers electrostatic discharge protection through the higher inductance component, and it enables low noise amplification through the lower inductance component. This multi-functional design reduces the need for separate components for each function.
3Reliability
If a first inductor is used to provide electrostatic discharge protection, then the amplifier is protected, but the inductance value may be too high causing noise issues
Solution Approach 1:
The patent segments the inductor function into two distinct components: a first inductor dedicated to electrostatic discharge protection with higher inductance value, and a second inductor dedicated to noise reduction and capacitance tuning with lower inductance value. Each inductor is optimized for its specific function, and their magnetic coupling allows them to work together as a unified tuning element without compromising either function.
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
This configuration effectively reduces noise, improves gain, and minimizes return loss by tuning out parasitic capacitance and providing efficient electrostatic discharge protection, enhancing the overall performance of the receiver front end module.
Implementation Method 1
a first inductor having a first terminal coupled to the input terminal and a second terminal configured to be coupled to the ground terminal, wherein the first inductor is arranged with a second inductor and configured to magnetically couple therewith
Implementation Method 2
the first inductor, in combination with said second inductor, is configured to tune out a parasitic capacitance at the input terminal
Data Source
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AI summary
A circuit comprising: an input terminal; a first amplifier (304) coupled to the input terminal of the circuit to receive an input signal; a first inductor (310) having a first terminal coupled to the input terminal and a second terminal configured to be coupled to the ground terminal, wherein the first inductor (310) is arranged with a second inductor (313) and configured to magnetically couple therewith, wherein said second inductor (313) is coupled to the first amplifier (304) and is configured to sense a current through the first amplifier (304).