GaN CMCD Transmitter Architecture for Multi-Standard RF Efficiency
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Solution Overview
Problem
Current RF transmitter devices face challenges in accommodating multiple high-PARP standards due to complexity, efficiency issues, and inability to handle future standards, with existing solutions introducing losses, ACPR issues, and spectral regrowth.
Innovation Solution
A reconfigurable RF transmitter architecture using digitally upconverted IF outphased signals and a Gallium Nitride (GaN) driver, with an output stage featuring an inverse Class-D configuration and on-chip driver circuitry, allowing for peak drain efficiency of at least 85% and accommodating multiple RF standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a parallel stack of power amplifiers is used to support multiple standards, then each standard can be served by a dedicated amplifier, but the device complexity and cost increase significantly
Solution Approach 1:
The patent implements a single power amplifier that can operate across multiple frequency bands (e.g., 700 MHz to 3.8 GHz) by using a wideband amplifier design with reconfigurable matching networks. This allows one amplifier to perform the function of multiple dedicated amplifiers, reducing device complexity while maintaining multi-standard support capability
2Adaptability or versatility
If conventional power amplifiers are used to handle high-PAPR signals, then the amplifier can cover a wide dynamic range, but the drain efficiency decreases
Solution Approach 1:
The patent segments the amplification function into two separate stages: a high-efficiency switchmode amplifier handling the constant envelope portion, and a linear amplifier handling the amplitude modulation portion. This segmentation allows each stage to operate in its optimal efficiency region, achieving peak drain efficiency of at least 85% while maintaining the ability to handle high-PAPR signals across the full dynamic range
3Ease of operation
If transmission lines are used in the amplifier architecture, then signal routing is achieved, but transmission losses are introduced
Solution Approach 1:
The patent replaces physical transmission lines with electrical interconnections and integrated circuit pathways on a common substrate. The switchmode amplifier and linear amplifier are electrically coupled through controlled impedance traces and coupling capacitors rather than using discrete transmission line components, thereby minimizing resistive losses and improving overall efficiency
Data Source
AI summary
A multi-standard transmitter architecture with digitally upconverted intermediate frequency (IF) outphased signals is disclosed. The transmitter architecture includes a Gallium Nitride (GaN) power amplifier (PA) circuit having a Current Mode Class-D (CMCD) configuration. The GaN PA circuit includes a lower switching device electrically coupled to an input to receive an input RF signal and an upper switching device to switchably electrically couple the first switching device to a power supply to drive an antenna circuit based on the input RF signal. Thus, a reconfigurable transmitter architecture is disclosed that utilizes a high-speed Gallium Nitride (GaN) driver to achieve a peak drain efficiency of at least 85% while delivering output power of 10 W at 1 GHz frequency, for example.