Cascode Amplifier Current Multiplication for Higher Linearity
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Solution Overview
Problem
Radar system amplifier circuits face challenges in achieving higher linearity while maintaining constant current consumption, as existing solutions either waste power or fail to effectively handle increased signal currents without sacrificing linearity.
Innovation Solution
The implementation of a current multiplication stage using cross-coupled common-base baluns in the amplifier circuit, which doubles or triples the output current without increasing intermodulation product levels, allowing for increased linearity and utilizing the additional current in other circuit components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bias current is increased in the entire cascode amplifier to improve linearity, then the linearity is improved, but the power consumption increases
Solution Approach 1:
The patent applies local quality by providing different bias currents to different stages of the amplifier. The transconductance stage receives a higher bias current (I_bias1) to improve linearity where it is most needed, while the current follower stage receives a lower bias current (I_bias2) to reduce unnecessary power consumption. This localized optimization resolves the contradiction by improving linearity only where required rather than uniformly across the entire amplifier.
2Use of energy by moving object
If the bias current is reduced in the current follower stage to decrease power consumption, then the power consumption is reduced, but the ability to handle signal current is reduced
Solution Approach 1:
The patent applies local quality by providing different bias currents to different stages of the amplifier. The transconductance stage receives a higher bias current (I_bias1) to improve linearity where it is most needed, while the current follower stage receives a lower bias current (I_bias2) to reduce unnecessary power consumption. This localized optimization resolves the contradiction by improving linearity only where required rather than uniformly across the entire amplifier.
3Productivity
If the signal current through the transconductance stage is increased to improve amplification, then the amplification is improved, but the amplitude of intermodulation products increases reducing linearity
Solution Approach 1:
The patent applies parameter changes by independently adjusting the bias current in the transconductance stage (I_bias1) to be higher than in the current follower stage. This parameter optimization allows the transconductance stage to operate at its optimal point for linearity, where it can handle the signal current more effectively and generate less intermodulation distortion, thereby improving overall amplifier linearity without sacrificing amplification capability.
Data Source
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AI summary
The present invention is about an Amplifier circuit (300, 400, 500, 600) for current amplification. The amplifier circuit (300, 400, 500, 600) comprises: an input stage adapted to receive an input signal; at least one current multiplication stage connected to the input stage; where the current multiplication stage is adapted to receive a current signal (ls?gnal) from the input stage and produce a multiplied output current signal (Iout) at an output of the amplifier circuit (300, 400, 500, 600). The current multiplication stage comprises at least two current multiplication circuits connected to each other, where each current multiplication circuit is adapted to produce an output current signal (Isignal) essentially equal to the current signal (Isignal) from the input stage, such that the output current signal (Iout) at an output of the amplifier circuit (300, 400, 500, 600) comprises a sum of the current signals (Isignal) received at each current multiplication circuit. Also a method of improving linearity in an amplification circuit is described.