RF Amplifier Supply Switching for APT and ET Linearity
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Solution Overview
Problem
Designing a power amplifier that performs well in both average power tracking (APT) and envelope tracking (ET) modes is challenging due to conflicting requirements, especially when supporting 5G NR carriers with wide bandwidth modulation, as previous solutions compromise system performance and stability.
Innovation Solution
A flexible PA supply interface architecture with a multi-switch network that configures for optimal APT or ET operation, allowing for adjustable capacitance and separate or common supply voltages, enabling simultaneous optimization in both modes without compromising performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a power amplifier is designed for average power tracking (APT) mode, then power efficiency is improved, but linearity and stability deteriorate when operating in envelope tracking (ET) mode
Solution Approach 1:
The patent implements dynamic switching between APT and ET operation modes based on signal conditions. The system can transition from static power supply (APT) to dynamic power supply (ET) tracking, allowing the amplifier to optimize power efficiency when appropriate while maintaining linearity and stability when needed. This is achieved through mode selection logic that monitors operating conditions and switches supply modes accordingly.
Solution Approach 2:
The patent changes the power supply voltage parameter dynamically by implementing an ET mode that tracks the envelope of the RF signal. The power supply voltage is modulated to follow the signal envelope, which improves linearity and stability during high-power operations. The system adjusts the supply voltage parameter based on the instantaneous signal conditions, enabling optimal performance across different operating points.
2Reliability
If a power amplifier is designed for envelope tracking (ET) mode, then linearity is improved, but power efficiency and adaptability deteriorate when operating in average power tracking (APT) mode
Solution Approach 1:
The system dynamically selects between ET and APT modes based on operating conditions. When the RF signal requires high linearity (such as during high-power transmission), the system switches to ET mode with dynamic power supply tracking. When operating at lower power levels where linearity requirements are reduced, the system switches to APT mode for improved power efficiency. This dynamic adaptation resolves the contradiction by applying the appropriate mode contextually.
Solution Approach 2:
The patent creates a universal power amplifier design that can operate in both APT and ET modes through a multi-functional power supply interface. The system incorporates switching circuitry and control logic that enables it to perform both APT (average power tracking) and ET (envelope tracking) functions using the same hardware platform. This multi-functionality allows the amplifier to adapt to different operational requirements without sacrificing either linearity or power efficiency.
3Device complexity
If fixed capacitance is used in power supply nodes, then circuit simplicity is maintained, but performance optimization for wide bandwidth 5G NR waveforms deteriorates
Solution Approach 1:
The patent implements adjustable capacitance values at the power supply nodes that can be dynamically configured based on the operating mode and signal bandwidth requirements. For wide bandwidth 5G NR waveforms, the system increases the capacitance values to maintain power supply stability during rapid envelope transitions. For narrower bandwidth operations, the capacitance can be reduced to simplify the circuit. This dynamic capacitance adjustment resolves the contradiction between circuit simplicity and wide bandwidth support.
Data Source
AI summary
An amplifier circuit assembly has a power supply that generates a supply voltage that changes based on a radio frequency signal and powers a cascade amplifier module. The amplifier modules amplifies the radio frequency signal and includes a first amplifier stage and a second amplifier stage configured to operate in respective operation modes. The first and second amplifier stages have first and second supply nodes floated from a ground by first and second adjustable capacitances, respectively. A switch connects or disconnects the first supply node and the second supply node depending on the respective operation modes.