Programmable Power Splitter Circuit for Doherty PA Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Doherty power amplifiers in wireless infrastructure base stations suffer from inefficiencies due to losses in the splitter circuit, which negatively impact the output performance.
Innovation Solution
A programmable splitter circuit using reactive components and isolation resistors/inductors to absorb reflected power, providing power matching and isolation, with adjustable power-split ratios and phase differences to optimize efficiency across varying load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed power splitter is used in Doherty PA, then the circuit structure is simple, but power efficiency deteriorates under varying load conditions
Solution Approach 1:
The patent applies dynamics by transforming the fixed splitter into a programmable splitter where capacitor values can be dynamically adjusted based on operating conditions. The splitter circuit includes multiple capacitors with different values that can be selectively connected to the signal path, allowing the power division ratio to adapt to different load conditions and maintain optimal efficiency across varying power levels.
2Loss of energy
If a programmable power splitter is used, then power efficiency is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the capacitor bank into multiple discrete capacitor elements with different values. Each capacitor can be independently controlled through separate control signals, allowing granular adjustment of the power division ratio. This segmented approach enables fine-tuned optimization of efficiency while keeping the control architecture manageable through modular design.
3Reliability
If isolation resistors are added to the splitter circuit, then isolation between output ports is improved, but power loss increases
Solution Approach 1:
The patent applies parameter changes by making the isolation resistance value programmable and adaptive. Rather than using a fixed high-value resistor that would cause constant power loss, the isolation resistance is adjusted dynamically based on operating conditions. The control circuit monitors the state of amplifiers and adjusts the isolation resistance to provide adequate isolation only when needed, minimizing power loss during normal operation while maintaining reliability when required.
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A device includes a splitter circuit including a first port configured to receive an input signal, a second port configured to provide a first output signal, and a third port configured to provide a second output signal. The splitter circuit includes an inductor including a first terminal coupled to the first port and a second terminal coupled to ground, a first capacitor circuit including a first terminal coupled to the first port and a second terminal coupled to the second port, a second capacitor circuit including a first terminal coupled to the first port and a second terminal coupled to the third port, and an isolation impedance coupled between the second port and the third port. The first capacitor circuit and the second capacitor circuit are programmable to provide a selected power-power split ratio between the first output signal and the second output signal.