Push-Pull Power Amplifier With Switchable Input Capacitance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing radio frequency (RF) communication systems face challenges in efficiently amplifying signals across multiple frequency bands, particularly in 5G communication standards, due to the need for separate power amplifiers for different frequency bands, which increases complexity and cost.
Innovation Solution
A reconfigurable push-pull power amplifier is designed with controllable input and output capacitance, along with a controllable ballasting network, to selectively amplify RF signals across different frequency bands, such as 5G N77 and N79, using a single amplifier architecture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate power amplifiers are used for different frequency bands, then amplification performance for each band is optimized, but device complexity and cost increase
Solution Approach 1:
The power amplifier is designed with reconfigurable input and output matching networks that can be tuned to different impedance values corresponding to different frequency bands. The amplifier core circuit remains the same, but the matching networks are reconfigured via control signals to adapt to N77, N79, and other 5G frequency bands, allowing one amplifier to perform multiple functions that previously required separate amplifiers
Solution Approach 2:
The matching networks incorporate switchable capacitor banks that can dynamically change their total capacitance based on the selected frequency band. Control logic receives band selection signals and activates specific capacitor combinations to adjust the input and output impedance matching, enabling the amplifier to adapt its characteristics in real-time according to the operating frequency band
2Reliability
If separate power amplifiers are used for different frequency bands, then amplification performance for each band is optimized, but manufacturing cost increases
Solution Approach 1:
By designing a single power amplifier that can be reconfigured for multiple frequency bands through switchable matching networks, the bill of materials is reduced compared to using separate amplifiers for each band. The same amplifier core is used across different bands, reducing component count and manufacturing complexity while maintaining optimized performance for each band through software-controlled matching network configuration
3Device complexity
If fixed input capacitance is used in power amplifier, then circuit design is simplified, but adaptability to different frequency bands is reduced
Solution Approach 1:
The input matching network incorporates switchable capacitor banks that can be dynamically configured to provide different total capacitance values. Based on the selected frequency band, control logic activates specific capacitor combinations to optimize the input impedance matching. This dynamic adjustment allows the amplifier to maintain optimal performance across N77, N79, and other frequency bands without requiring completely different amplifier designs for each band
Data Source
AI summary
Apparatus and methods for reconfigurable power amplifiers are disclosed. In certain embodiments, a mobile device includes a transceiver configured to generate a first radio frequency signal of a first frequency band and a second radio frequency signal of a second frequency band, and a front-end system including a push-pull power amplifier configured to selectively amplify one of the first radio frequency signal or the second radio frequency signal based on a band control signal. The push-pull power amplifier includes an input balun, an output balun, and a pair of amplifiers coupled between the input balun and the output balun. The band control signal is operable to control an input capacitance of the pair of amplifiers.