CMOS Power Controller Flat Amplitude Phase Response
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Solution Overview
Problem
Traditional power amplifier control systems in wireless communication devices suffer from inefficiencies, non-linearity, and power wastage due to amplitude and phase distortion, leading to shorter battery life and increased costs, especially in multi-mode and multi-band operations like EDGE and WCDMA.
Innovation Solution
A CMOS power controller with independent GaAs power amplifiers and a low-dropout amplifier is used to provide a constant input voltage, optimizing circuit efficiency and reducing distortion through an open-loop polar modulation scheme, which includes a bandgap bias generator, bias buffers, and a gain setting amplifier to manage power delivery efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a power-sensing closed-loop control method is used, then power detection capability is provided, but the system becomes more complex, larger, and more costly
Solution Approach 1:
The patent extracts the power detection function from the main control system by implementing a separate power detector module that interfaces with the power amplifier. This allows power sensing capability to be added without fundamentally redesigning the entire control system, reducing the complexity impact while maintaining measurement precision.
Solution Approach 2:
The patent introduces a power detector as an intermediary component between the power amplifier and the control logic. This mediator converts the power amplifier's output power into a measurable voltage signal, enabling closed-loop control without requiring direct integration of detection capabilities into the amplifier itself, thus managing system complexity.
2Measurement precision
If a power detector and directional coupler are used for feedback, then power detection is enabled, but the device size increases
Solution Approach 1:
The patent implements a nested architecture where the power detector is integrated within the existing control chip structure. The power detection circuitry is embedded in the control logic area, and the directional coupler is integrated with the power amplifier stage, allowing these components to share space efficiently rather than adding separate discrete modules.
3Reliability
If traditional closed-loop power control is implemented, then power feedback is provided, but calibration time increases and non-linearity issues arise
Solution Approach 1:
The patent implements preliminary calibration during the manufacturing process, storing calibration data in lookup tables within the control chip. This preliminary action eliminates the need for field calibration, reducing calibration time to zero for end users while maintaining power control accuracy through pre-characterized compensation for non-linearity.
Solution Approach 2:
The patent creates a simplified model of the power amplifier's non-linear behavior through lookup tables that store pre-measured transfer characteristics. This copying approach allows the control system to compensate for non-linearity using simple table lookups rather than complex real-time calculations, maintaining accuracy while minimizing processing time and calibration requirements.
4Use of energy by moving object
If power amplifier efficiency is improved, then battery life increases, but distortion may increase without proper linearization
Solution Approach 1:
The patent implements a closed-loop feedback system where the power detector monitors the actual output power, and the control logic adjusts the power amplifier's input signal accordingly. This feedback mechanism allows the system to operate the power amplifier at high efficiency points while continuously correcting for any amplitude and phase distortion, maintaining signal quality despite efficient but potentially non-linear operation.
Solution Approach 2:
The patent dynamically changes the operating parameters of the power amplifier based on the desired output power level. By adjusting bias conditions and input signal characteristics in real-time, the system optimizes the power amplifier's efficiency at each operating point while maintaining linear operation through coordinated control of multiple parameters.
Data Source
AI summary
A method for operating a power controller in a wireless communication device is provided that includes generating a power controller output signal using an open loop polar modulation scheme. The power controller output signal is operable to control the power delivered to a high-band power amplifier and a low-band power amplifier. A band state is determined for the wireless communication device. The power controller output signal is provided to the high-band power amplifier when the band state is a high-band state and to the low-band power amplifier when the band state is a low-band state.