Multi-Carrier Power Tracking for RF Amplifier Supply Voltage
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Solution Overview
Problem
Wireless devices face inefficiencies in generating power supply voltages for power amplifiers handling multiple transmit signals simultaneously, leading to wasted power and potential intermodulation distortion due to the power supply voltage not tracking the envelope of the output RF signal.
Innovation Solution
A power tracking system that determines a power tracking signal based on the in-phase and quadrature components of multiple transmit signals and generates a power supply voltage to match the envelope of the output RF signal, using a power tracker and power supply generator to optimize the power supply voltage for a single or multiple power amplifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate power amplifiers are used for each transmit signal, then each signal can be amplified independently with proper power tracking, but the device complexity and cost increase significantly
Solution Approach 1:
The patent combines multiple power amplifiers into a single shared power amplifier that processes multiple transmit signals simultaneously. This merging approach reduces the number of power amplifier circuits while maintaining power tracking capability through a unified power supply generator that receives combined I and Q components from all transmit signals.
Solution Approach 2:
The single power amplifier is designed to handle multiple transmit signals across different frequency carriers, making it a multi-functional device. The power supply generator similarly serves multiple signals by processing aggregated I and Q components, providing universal power tracking for all transmit signals rather than dedicated tracking for each signal.
2Device complexity
If a fixed power supply voltage is used for the power amplifier, then the circuit is simple to implement, but power-added efficiency decreases due to wasted power when the power supply voltage does not track the signal envelope
Solution Approach 1:
The patent transitions from a fixed power supply voltage to a dynamic power supply voltage that tracks the envelope of the combined transmit signals. The power supply generator continuously adjusts the power supply voltage based on real-time I and Q component inputs, making the power supply adaptive to signal variations and improving power-added efficiency.
Solution Approach 2:
The power supply generator implements feedback by continuously monitoring the I and Q components of the transmit signals and adjusting the power supply voltage accordingly. This closed-loop approach ensures the power supply voltage matches the signal envelope, minimizing wasted power while maintaining efficiency.
3Device complexity
If the power supply voltage does not track the envelope of the output RF signal, then the power amplifier can operate with a simple fixed voltage supply, but intermodulation distortion increases due to inefficient power delivery
Solution Approach 1:
The power supply voltage is made dynamic by continuously adjusting it to match the envelope of the combined transmit signals. This dynamic adjustment is achieved through the power supply generator that processes I and Q components in real-time, ensuring the power supply voltage adapts to signal variations and reduces intermodulation distortion.
Solution Approach 2:
The patent changes the power supply voltage parameter from a fixed value to a time-varying value that tracks the signal envelope. This parameter change is implemented through the power supply generator that modulates the power supply voltage based on the instantaneous I and Q component magnitudes, thereby reducing intermodulation distortion.
Data Source
AI summary
Techniques for generating a power tracking supply voltage for a circuit (e.g., a power amplifier) are disclosed. The circuit may process multiple transmit signals being sent simultaneously on multiple carriers at different frequencies. In one exemplary design, an apparatus includes a power tracker and a power supply generator. The power tracker determines a power tracking signal based on inphase (I) and quadrature (Q) components of a plurality of transmit signals being sent simultaneously. The power supply generator generates a power supply voltage based on the power tracking signal. The apparatus may further include a power amplifier (PA) that amplifies a modulated radio frequency (RF) signal based on the power supply voltage and provides an output RF signal.