Switchable RF Power Amplifier Circuit for Multi-Band Transmission
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Solution Overview
Problem
Conventional radio frequency circuits face an increase in circuit scale when designed to handle simultaneous transmission of multiple radio frequency signals in high power classes.
Innovation Solution
A radio frequency circuit configuration with multiple power amplifiers, filters, and switches that allow for simultaneous transmission of multiple radio frequency signals while suppressing circuit scale expansion, utilizing a Doherty amplifier structure and switchable connections to manage power amplifiers and filters efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple power amplifiers and filters are added to handle simultaneous transmission of multiple radio frequency signals in high power classes, then the transmission capability is improved, but the circuit scale increases
Solution Approach 1:
The first power amplifier is configured to serve multiple functions: it can amplify signals for the first band through the first filter, amplify signals for the second band through the second filter, and combine with the second power amplifier to form a Doherty amplifier structure. This multi-functionality allows a single power amplifier to handle multiple frequency bands and transmission modes, reducing the need for separate amplifiers for each band and thereby suppressing circuit scale expansion while maintaining high power class transmission capability across multiple bands
Solution Approach 2:
The patent employs switches to dynamically reconfigure the circuit connections between power amplifiers, filters, and antenna terminals. The first switch connects the first power amplifier to either the first filter or the second filter based on the required transmission band. The second switch connects the second power amplifier to either the second filter or combines with the first power amplifier for Doherty operation. This dynamic switching capability enables the circuit to adapt its configuration for different transmission scenarios, allowing a single power amplifier to serve multiple bands and modes, thus improving transmission capability without proportionally increasing circuit scale
2Use of energy by moving object
If a Doherty amplifier structure is used to improve power efficiency, then power efficiency is improved, but the circuit configuration becomes more complex
Solution Approach 1:
The first power amplifier is designed to perform multiple functions: it can operate independently to amplify signals for the first band, amplify signals for the second band when connected through the second switch, and combine with the second power amplifier to form a Doherty amplifier structure. This multi-functionality allows the Doherty configuration to be implemented only when needed for high power class transmission in the second band, rather than requiring a dedicated Doherty structure for each band, thereby improving power efficiency while limiting the increase in circuit configuration complexity
Solution Approach 2:
The patent uses switches to dynamically configure the Doherty amplifier structure only when required. The second switch enables the first power amplifier to connect to either the second filter (for independent second band transmission) or to combine with the second power amplifier (for Doherty operation). This dynamic configuration allows the system to switch between conventional and Doherty amplifier modes based on transmission requirements, achieving improved power efficiency through Doherty operation when needed while avoiding the permanent complexity of having multiple fixed Doherty structures
Data Source
AI summary
A radio frequency circuit includes: an antenna connection terminal; an antenna connection terminal; a first power amplifier; a second power amplifier; a first filter in a first signal path between the antenna connection terminal and the first power amplifier and having a passband including a transmission band of a first band; a second filter in a second signal path between the antenna connection terminal and the second power amplifier and having a passband including a transmission band of a second band; and a switch configured to selectively couple an output of the power amplifier and one of the first signal path and the second signal path.