Multiband Power Amplifier Output Matching for Wider VBW
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Solution Overview
Problem
Conventional multiband power amplifier circuits face challenges in increasing video bandwidth (VBW) while maintaining linear correction and reducing circuit losses, often introducing additional resonance points and inefficiencies with the use of LC resonance circuits and resistors.
Innovation Solution
The proposed multiband power amplifier circuit design eliminates the LC resonance circuit and resistor, utilizing a direct connection between the output ends of power transistors through a matching circuit that decreases equivalent inductance, thereby increasing the VBW and improving fundamental wave matching bandwidth without introducing additional resonance points or losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a first-order or multi-order low-pass network is added to the drain of a power transistor to increase VBW, then the VBW is increased, but additional resonance points are introduced affecting linear correction and circuit losses increase
Solution Approach 1:
The patent removes the traditional low-pass network (LC resonance circuit and resistor) from the drain of the power transistor. Instead, it introduces a third matching circuit that directly connects the output ends of multiple power transistors, extracting the problematic resonance-reducing components while maintaining VBW enhancement through parallel connection architecture
Solution Approach 2:
The third matching circuit serves as an intermediary element that directly connects the output ends of the first and second power transistors. This intermediary structure eliminates the need for traditional low-pass networks and resistors, thereby reducing circuit losses while maintaining the desired VBW performance
2Use of energy by moving object
If an LC resonance circuit is added to increase VBW, then the VBW is increased, but additional resonance points are introduced affecting linear correction
Solution Approach 1:
The patent extracts and removes the LC resonance circuit from the traditional multiband power amplifier architecture. By eliminating this component, the unwanted additional resonance points that degrade linear correction are removed, while the VBW enhancement is achieved through the alternative third matching circuit configuration
Solution Approach 2:
The patent converts the harmful effect of additional resonance points into a benefit by redesigning the output connection architecture. The third matching circuit directly connecting power transistor outputs transforms the potential resonance problem into an opportunity for simplified circuit design that maintains both wide bandwidth and excellent linear correction
3Stability of the object's composition
If a resistor is added to reduce resonance point quality factor, then the resonance is dampened, but additional losses are introduced
Solution Approach 1:
The patent removes the resistor from the circuit architecture entirely. Instead of using a resistor to dampen resonance (which introduces losses), the design relies on the third matching circuit's direct connection topology to naturally control resonance characteristics without energy-dissipating components
Solution Approach 2:
The third matching circuit performs the dual function of connecting power transistor outputs and naturally controlling resonance characteristics without requiring additional loss-introducing components. The circuit structure itself provides the necessary resonance management through its inherent electrical characteristics
4Device complexity
If traditional matching circuits are used between power transistors, then the circuit structure is simple, but the VBW and fundamental wave matching bandwidth are limited
Solution Approach 1:
The patent merges the functions of traditional matching circuits with a new direct-connection architecture. The third matching circuit combines the output connections of multiple power transistors in parallel, simultaneously achieving simplified structure and enhanced VBW and fundamental wave matching bandwidth through the unified connection topology
Data Source
AI summary
Embodiments of this application provide a multiband power amplifier circuit and a radio frequency transceiver, to increase a VBW while ensuring linear correction and reducing a circuit loss. The multiband power amplifier circuit includes a first power transistor, a second power transistor, a first matching circuit, a second matching circuit, a third matching circuit, and a combiner. The first power transistor is coupled to a first input end of the combiner via the first matching circuit. The second power transistor is coupled to a second input end of the combiner via the second matching circuit. A first end of the third matching circuit is coupled to an output end of the first power transistor, and a second end of the third matching circuit is coupled to an output end of the second power transistor.