Switched Input Attenuator for Multi-Mode RF Amplifier Calibration
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Solution Overview
Problem
RF power amplifier systems face challenges in satisfying performance requirements across different modes of operation due to varying input signals, necessitating different calibrations for each mode.
Innovation Solution
A switched input attenuator is coupled between the input and output of the RF power amplifier system, allowing selective attenuation or bypass of input signals based on the mode of operation, using multiple attenuation cells and bypass paths controlled by a controller to maintain consistent performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If different calibrations are used for each mode of operation, then performance requirements are satisfied across different modes, but device complexity increases
Solution Approach 1:
The patent implements a universal calibration approach where a single calibration procedure is designed to work across multiple operating modes (envelope tracking and average power tracking modes) by using a switched input attenuator that can be configured in different states. This allows one calibration process to satisfy performance requirements for all modes, eliminating the need for separate calibrations for each mode and thereby reducing device complexity while maintaining reliability.
2Reliability
If input signal attenuation is adjusted for different modes, then power gain and amplification linearity are improved, but device complexity increases
Solution Approach 1:
The patent employs a dynamic switched input attenuator that can change its attenuation state based on the operating mode. The attenuator includes multiple attenuation cells that can be selectively activated or deactivated through switching mechanisms, allowing the system to dynamically adjust input signal attenuation levels. This dynamic configuration enables optimization of power gain and amplification linearity for different modes without requiring complex separate attenuation control systems for each mode.
3Adaptability or versatility
If multiple attenuation cells are used for different attenuation levels, then adaptability to different input signals is improved, but device complexity increases
Solution Approach 1:
The patent divides the input attenuator into multiple discrete attenuation cells, each providing a specific attenuation level. These segmented cells can be independently controlled through switching mechanisms, allowing the system to select appropriate attenuation levels for different input signal characteristics and operating modes. This segmentation provides adaptability to various input signals while keeping each individual attenuation cell relatively simple in structure.
Solution Approach 2:
The attenuation cells are configured in a nested or cascaded arrangement where multiple cells can be selectively engaged in series or parallel configurations. This nesting approach allows different combinations of attenuation cells to be activated depending on the required attenuation level, providing versatile input signal handling capability while efficiently utilizing the attenuator structure without requiring completely separate attenuation paths for each level.
Data Source
AI summary
A radio frequency power amplifier system includes an input to receive an input signal; an output to provide an amplified signal; a switched input attenuator coupled to the input and including an attenuation path having an attenuation cell and a bypass path in parallel with the attenuation path, the bypass path configured to selectively bypass the attenuation cell; a radio frequency power amplifier coupled between the switched input attenuator and the output, the radio frequency power amplifier having a plurality of modes of operation including a first mode and a second mode different from the first mode; and a controller coupled to the switched input attenuator and configured to control an operational state of the switched input attenuator based on a mode of operation of the radio frequency power amplifier.