Two-Stage Voltage-to-Current Converter for Third Harmonic Cancellation
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Solution Overview
Problem
Voltage-to-current converters suffer from third harmonic distortion due to nonlinearity in their transfer function, which degrades amplifier performance and introduces distortion in output signals, with existing linearization techniques often increasing noise, power consumption, or higher-order nonlinearity.
Innovation Solution
A two-stage voltage-to-current converter design is implemented, where the first stage has compressive nonlinearity and the second stage has expansive nonlinearity, cascaded to cancel third harmonic distortion, with negligible increase in noise or power consumption, and can be used in conjunction with other linearization techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a voltage-to-current converter is used in the input stage of an amplifier, then the input voltage signal is converted into a current signal for amplification, but nonlinearity in the transfer function causes distortion in the output signal
Solution Approach 1:
The voltage-to-current converter is divided into two cascaded stages: a first stage that provides compressive nonlinearity and a second stage that provides expansive nonlinearity. This segmentation allows each stage to have specific nonlinearity characteristics that, when combined, cancel out third-order harmonic distortion while maintaining signal amplification capability.
Solution Approach 2:
The patent combines two different nonlinearity types (compressive and expansive) in a composite two-stage converter architecture. The first stage uses a differential pair configuration that produces compressive nonlinearity, while the second stage is designed to produce expansive nonlinearity, creating a composite system where the nonlinearities compensate for each other.
2Object-generated harmful factors
If existing linearization techniques are applied to reduce distortion, then harmonic distortion is reduced, but noise and power consumption increase
Solution Approach 1:
Instead of trying to eliminate nonlinearity through traditional linearization techniques that consume additional power, the patent converts the harmful nonlinearity into a beneficial property by designing two stages with complementary nonlinearities. The compressive nonlinearity of the first stage and expansive nonlinearity of the second stage work together to cancel distortion, turning what was previously a harmful effect into the mechanism for distortion cancellation.
3Object-generated harmful factors
If existing linearization techniques are applied to reduce distortion, then harmonic distortion is reduced, but noise increases
Solution Approach 1:
The patent transforms the harmful nonlinearity into a beneficial cancellation mechanism. By designing the first stage with compressive nonlinearity and the second stage with expansive nonlinearity, the system uses the nonlinearities themselves to cancel third-order harmonics, avoiding the need for additional linearization circuits that would introduce more noise.
Solution Approach 2:
The patent changes the operational parameters of the two stages by configuring them with different nonlinearity characteristics. The first stage operates in a regime that produces compressive nonlinearity, while the second stage is biased and designed to produce expansive nonlinearity. This parameter change approach allows distortion cancellation without requiring additional active elements that would increase noise.
Data Source
AI summary
A voltage-to-current converter that reduces third harmonic distortion. An amplifier includes an input stage. The input stage includes a first voltage-to-current conversion stage and a second voltage-to-current conversion stage. The first voltage-to-current conversion stage is configured to provide an input to output gain with compressive nonlinearity. The second voltage-to-current stage is cascaded with the first voltage-to-current conversion stage. An input of the second voltage-to-current stage is connected to an output of the first voltage-to-current conversion stage. The second voltage-to-current conversion stage is configured to provide an input to output gain with expansive nonlinearity.