Symmetrical Doherty Amplifier Stages for DC-to-RF Efficiency
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Solution Overview
Problem
Doherty amplifiers face challenges with poor DC-to-RF conversion efficiency and signal quality due to asymmetric design and large design footprints, requiring increased design effort and inefficiencies in current implementations.
Innovation Solution
The implementation of symmetrical amplifier stages within a single package, where each amplifier path includes identical transistor sizes and matching networks, allowing for flexible configuration as either main or peaking amplifiers, and the use of phase inversion elements in input and output networks to ensure in-phase summation of currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If asymmetric amplifier stages are used in Doherty amplifiers, then the amplifier can achieve desired performance with main and peaking stages, but the design complexity and footprint increase significantly
Solution Approach 1:
The patent applies asymmetry by configuring one amplifier stage as a main amplifier and another as a peaking amplifier with different bias conditions and operating characteristics, allowing the Doherty amplifier to achieve efficient power amplification across different power levels while maintaining manageable design complexity through systematic asymmetry implementation
2Use of energy by moving object
If asymmetric amplifier stages with different transistor sizes are used, then the amplifier can operate efficiently at different power levels, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by assigning different transistor sizes and bias conditions to specific amplifier stages (main vs. peaking) to optimize their individual performance characteristics, allowing each stage to operate efficiently in its designated power range while maintaining overall system efficiency
3Area of stationary object
If multiple amplifier stages are integrated in a single package, then the footprint is reduced, but the ease of manufacture decreases due to increased integration complexity
Solution Approach 1:
The patent applies merging by integrating multiple amplifier stages, impedance matching networks, and associated circuitry into a single packaged component, reducing the overall design footprint and simplifying system integration while maintaining manufacturing feasibility through modular integration approaches
4Reliability
If phase shift networks are added to ensure in-phase current summation, then signal quality improves, but the device complexity increases
Solution Approach 1:
The patent applies equipotentiality by incorporating phase shift networks that adjust the phase of signals from different amplifier stages to ensure they are in-phase at the summation point, maximizing constructive interference and signal quality while managing complexity through systematic phase alignment
Data Source
AI summary
An embodiment of an electrical device includes a device package and a plurality of amplifier paths physically contained by the device package. Each amplifier path includes an amplifier stage electrically coupled between an input and an output to the amplifier stage, and the amplifier stages of the plurality of amplifier paths are symmetrical. In a further embodiment, the amplifier paths have translational symmetry within the device package. In another further embodiment, transistors comprising the amplifier stages of the plurality of amplifier paths are substantially identical in size. The electrical device may be incorporated into an amplifier system that further includes an external input network and an external output network. For example, the amplifier system may be configured in a Doherty amplifier topology.