Power Amplifier Trimming Using DPD Coefficients for RF Efficiency
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Solution Overview
Problem
Power amplifiers in RF communication systems face challenges in efficiently managing power levels and prolonging battery life, particularly in 5G communication standards, due to the complexity of features like carrier aggregation, beamforming, and high spectral efficiency, which demand precise adjustments and trimming to maintain performance and efficiency.
Innovation Solution
The implementation of a transmit circuit in mobile devices that includes digital pre-distortion circuits, a coefficient comparator circuit to generate trimming control signals, and a power amplifier trimming circuit to adjust power amplifiers by methods such as transistor, feedback capacitor, bias, or load line adjustments, allowing for efficient power management and reduced power consumption by enabling mode transitions based on coefficient comparisons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple digital pre-distortion circuits are used to provide digital pre-distortion to each digital transmit signal separately, then the linearity and efficiency of power amplifiers are improved, but the device complexity and power consumption increase
Solution Approach 1:
Multiple digital pre-distortion circuits are merged into a single shared digital pre-distortion circuit. The coefficient comparator circuit compares coefficients from multiple power amplifiers and generates a single trimming control signal that is applied to the shared circuit, reducing device complexity while maintaining linearity through coefficient-based trimming.
Solution Approach 2:
A single digital pre-distortion circuit is designed to serve multiple power amplifiers universally. The circuit can be dynamically configured to handle different numbers of power amplifiers (e.g., 1, 2, 3, or 4) through the trimming control signal, making the circuit multi-functional and reducing overall device complexity.
2Reliability
If multiple digital pre-distortion circuits are used to provide digital pre-distortion to each digital transmit signal separately, then the linearity and efficiency of power amplifiers are improved, but the power consumption increases
Solution Approach 1:
Multiple power-consuming digital pre-distortion circuits are merged into one shared circuit, directly reducing power consumption. The coefficient comparator circuit enables this consolidation by comparing coefficients and generating a single trimming control signal that maintains linearity across multiple power amplifiers using the shared circuit.
Solution Approach 2:
The system uses the coefficient comparator circuit to automatically determine the optimal configuration of the shared digital pre-distortion circuit based on the number of active power amplifiers. This self-service mechanism dynamically adjusts the circuit operation to maintain linearity while minimizing power consumption without requiring multiple separate circuits.
3Loss of energy
If power amplifiers are trimmed using transistor, feedback capacitor, bias, or load line adjustments, then the efficiency and power level management are improved, but the device complexity increases
Solution Approach 1:
The trimming control signal dynamically changes parameters of the power amplifiers, including transistor characteristics, feedback capacitor values, bias levels, and load line configurations. This parameter-based approach improves efficiency by optimizing amplifier operation while avoiding the need for complex physical adjustment mechanisms.
Solution Approach 2:
The coefficient comparator circuit provides feedback by comparing coefficients from multiple power amplifiers and generating appropriate trimming control signals. This feedback mechanism enables automatic optimization of amplifier efficiency through parameter adjustments without requiring complex manual trimming circuits.
Data Source
AI summary
Apparatus and methods for power amplifier trimming based on coefficients for digital pre-distortion (DPD) are disclosed. In certain embodiments, a mobile device includes a transmit circuit that generates a plurality of digital transmit signals. The transmit circuit includes a plurality of DPD circuits each operable to provide DPD to a corresponding one of the digital transmit signals, a coefficient comparator circuit that generates a trimming control signal based on a plurality of coefficients of the plurality of DPD circuits, and a plurality of digital to radio frequency (RF) converters that convert the digital transmit signals into a plurality of RF signals. The mobile device further includes a front end system including a plurality of power amplifiers each amplifying a respective one of the RF signals, and a power amplifier trimming circuit that controls trimming of the power amplifiers based on the trimming control signal.