Differential Amplifier Bias Correction for Even-Order Distortion
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Solution Overview
Problem
In pseudo differential type power amplifiers, even number-order distortion is difficult to remove due to mismatches in single-phase circuitries amplifying differential input signals, leading to output signal distortion.
Innovation Solution
An amplifier circuitry comprising a first and second amplifier, a voltage generating circuitry, and a control circuitry that adjusts bias voltages to minimize the difference between the DC components of the outputs from both amplifiers, thereby reducing second-order distortion by using a balun, capacitors, resistors, and a comparator circuit to control the bias voltage application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If pseudo differential type power amplifier is used, then power amplification is achieved, but even number-order distortion cannot be removed due to mismatch in single-phase circuitries
Solution Approach 1:
The invention introduces a feedback mechanism where the output signal is fed back to the input side through a feedback capacitor. This feedback allows the even number-order distortion components to be canceled by creating a corrective signal that opposes the distortion, thereby reducing the harmful distortion while maintaining power amplification capability
Solution Approach 2:
The invention changes the operating parameters by applying different DC voltage levels to the positive and negative signal lines. By adjusting these DC voltage parameters independently, the system can optimize the operating point of each transistor to minimize mismatch and reduce even number-order distortion while maintaining power amplification
2Power
If mismatch in single-phase circuitries is present, then power amplification operates, but even number-order distortion is generated in output signal
Solution Approach 1:
The feedback mechanism captures the distortion generated by mismatched circuitries and feeds it back to the input through a feedback capacitor. This creates a corrective action that counteracts the distortion, improving output signal quality while maintaining power amplification function
Solution Approach 2:
The invention creates a copied version of the output signal and uses it in a differential configuration. By copying the output and processing it through the feedback path, the system can identify and cancel distortion components, thereby improving signal quality without sacrificing power amplification capability
Data Source
AI summary
An amplifier circuitry includes a first amplifier, a second amplifier, a voltage generating circuitry, and a control circuitry. The first amplifier circuitry configured to amplify a first signal. The second amplifier circuitry configured to amplify a second signal which forms differential signals together with the first signal. The voltage generating circuitry configured to generate at least one of a first bias voltage to be applied to the first signal and a second bias voltage to be applied to the second signal. The control circuitry configured to control the voltage generation circuitry so as to decrease a difference between a DC component of an output of the first amplifier circuitry and a DC component of an output of the second amplifier circuitry.