Differential Power Amplifier Bias Control via Transformer Midpoint
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power amplifier circuits with differential amplifier circuits face issues with gain dispersion affecting symmetry, particularly when using envelope tracking, leading to asymmetrical arrangements and potential malfunctions.
Innovation Solution
A power amplifier circuit design that includes a differential amplifier circuit, a transformer, and an adjustment circuit coupled to the transformer's midpoint, which adjusts bias current or voltage based on envelope-controlled supply voltage to maintain symmetry and achieve appropriate gain dispersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If an adjustment circuit is added to control gain dispersion in envelope tracking, then power efficiency is improved, but circuit complexity increases
Solution Approach 1:
The patent introduces a transformer as an intermediary component between the differential amplifier circuit and the adjustment circuit. The transformer's primary winding is connected to the output of the differential amplifier circuit, and its secondary winding is connected to the adjustment circuit. This intermediary structure allows the adjustment circuit to control gain dispersion without directly interfering with the differential amplifier circuit's operation, thereby improving power efficiency while minimizing the impact on circuit complexity.
2Use of energy by moving object
If gain dispersion is adjusted to improve power efficiency, then energy consumption is reduced, but symmetry of the differential amplifier circuit is affected
Solution Approach 1:
The patent segments the circuit into distinct functional blocks: the differential amplifier circuit and the adjustment circuit, connected through a transformer. This segmentation allows the adjustment circuit to independently control gain dispersion for power efficiency optimization without disrupting the symmetry and operational integrity of the differential amplifier circuit. Each segment can be optimized for its specific function while maintaining overall system performance.
3Device complexity
If the adjustment circuit is directly connected to the differential amplifier circuit, then gain control is simplified, but malfunctions due to fluctuating RF signals may occur
Solution Approach 1:
The transformer serves as an intermediary that isolates the adjustment circuit from direct connection to the differential amplifier circuit. This isolation prevents fluctuating RF signals from causing malfunctions in the adjustment circuit while still allowing the circuit to achieve its gain control function. The transformer's magnetic coupling enables signal transfer without direct electrical connection, thereby improving reliability.
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 design maintains symmetry of the differential amplifier circuit while achieving wide-ranging gain variations, reducing circuit size, and preventing malfunctions due to fluctuating radio-frequency signals.
Implementation Method 1
The transformer includes a primary winding and a secondary winding
Data Source
AI summary
A power amplifier circuit includes a differential amplifier circuit configured to amplify a radio-frequency signal, a transformer disposed on an output side with respect to the differential amplifier circuit and including a primary winding and a secondary winding, and a dispersion circuit coupled to a midpoint of the primary winding of the transformer and configured to operate as an adjustment circuit. The dispersion circuit is configured to adjust, based on a supply voltage controlled in accordance with the envelope of the radio-frequency signal, a bias (bias current or bias voltage) to be supplied to the differential amplifier circuit.