Envelope Tracker With Multi-Level Supply Modulation for RF Power Amplifiers
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Solution Overview
Problem
Existing power amplifiers in RF communication systems face inefficiencies in managing RF signal power, leading to reduced battery life and increased heat generation, particularly in managing the envelope of RF signals across varying communication standards like 5G NR.
Innovation Solution
A mobile device with an envelope tracker system that includes a multi-level supply modulator and control circuit, capable of selectively connecting different regulated voltages to the power amplifier supply voltage, providing a gradual transition and operating in both envelope tracking and average power tracking modes to optimize power efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a power amplifier is used to amplify RF signals in RF communication systems, then the transmit power level is increased, but power consumption increases and battery life is reduced
Solution Approach 1:
The patent applies dynamics by making the power amplifier supply voltage dynamic rather than fixed. The envelope tracker continuously adjusts the supply voltage to the power amplifier based on the instantaneous envelope of the RF signal, allowing the amplifier to operate at optimal power levels for each signal condition rather than running at constant high power, thus reducing overall power consumption while maintaining required transmit power levels when needed
Solution Approach 2:
The patent changes the parameter of supply voltage from a constant value to a dynamically varying parameter that tracks the signal envelope. By modifying the supply voltage parameter in real-time according to the RF signal characteristics, the system achieves better power efficiency without compromising the ability to deliver high transmit power when the signal requires it
2Power
If a power amplifier is used to amplify RF signals in RF communication systems, then the transmit power level is increased, but heat generation increases
Solution Approach 1:
The dynamic adjustment of supply voltage reduces the time the power amplifier operates at high power levels, thereby reducing cumulative heat generation. The envelope tracker ensures the amplifier only operates at high voltage when the signal envelope requires high power, minimizing thermal stress and heat accumulation in the amplifier components
3Loss of energy
If an envelope tracker with multi-level supply modulator is used to control power amplifier supply voltage, then power added efficiency is enhanced, but device complexity increases
Solution Approach 1:
The patent segments the supply voltage control into multiple discrete levels rather than using a continuous analog control. The multi-level supply modulator divides the voltage range into several stepped levels, each corresponding to different signal envelope conditions. This segmentation simplifies the control architecture compared to continuous control while still achieving significant power added efficiency improvements through selective voltage switching
Solution Approach 2:
The envelope tracker acts as an intermediary device between the battery/power source and the power amplifier. It mediates the power delivery by conditioning the supply voltage according to the signal envelope, isolating the power amplifier from direct battery connection and enabling efficient power transfer through intelligent voltage management rather than requiring complex modifications to the amplifier itself
Data Source
AI summary
Envelope tracking systems for power amplifiers are provided herein. In certain embodiments, an envelope tracker is provided for a power amplifier that amplifies a radio frequency (RF) signal. The envelope tracker controls a power amplifier supply voltage of the power amplifier based on an envelope signal indicating an envelope of the RF signal. The envelope tracker includes a first controllable resistance between a first regulated voltage and the power amplifier supply voltage and a second controllable resistance between a second regulated voltage and the power amplifier supply voltage. The first regulated voltage and the second regulated voltage are of different voltage levels.