Envelope Tracking Modulator with Adapted Static Voltage for RF Efficiency
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Solution Overview
Problem
Conventional wireless communication devices face inefficiencies in power amplifiers, leading to reduced communication time, increased heat removal needs, and higher operational costs, particularly due to low power-added efficiency in RF power amplifiers.
Innovation Solution
A power amplifier device with an envelope tracking modulator that adjusts static and dynamic voltages based on measurements from a power sensor to maintain peak efficiency, using a matching circuit with components like PIN diodes and varicap diodes to ensure optimal operating conditions, compliant with standards like WCDMA or LTE.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional power amplifiers are used in wireless devices, then the device can transmit RF signals, but the power amplifier consumes most of the power resulting in low power-added efficiency
Solution Approach 1:
The patent implements envelope tracking that dynamically adjusts the supply voltage to the power amplifier based on the instantaneous envelope of the modulated signal. This dynamic voltage adjustment allows the amplifier to operate at optimal efficiency points across varying signal conditions, transforming the static operation into adaptive dynamic operation that maintains high efficiency throughout the signal cycle.
Solution Approach 2:
The invention changes the operating parameters of the power amplifier by varying the supply voltage in real-time according to the signal envelope. This parameter change enables the amplifier to operate in different regions of its efficiency curve, selecting the most efficient operating point for each instantaneous condition, thereby improving overall power-added efficiency.
2Duration of action of stationary object
If the power amplifier efficiency is low, then the wireless device can operate continuously, but the communication time is reduced for a given battery life
Solution Approach 1:
The system employs feedback mechanisms where the envelope detector monitors the output signal and feeds back control information to the voltage regulator. This closed-loop feedback ensures that the supply voltage continuously tracks the signal envelope, maintaining optimal efficiency and maximizing communication time for a given battery capacity.
3Loss of energy
If power amplifier efficiency is low, then the device can function, but heat removal requirements increase
Solution Approach 1:
By dynamically adjusting the supply voltage to match the signal envelope, the system minimizes the voltage differential across the amplifier device at any given moment. This dynamic operation reduces power dissipation and heat generation compared to static high-voltage operation, lowering thermal management requirements.
4Loss of energy
If Doherty amplifier is used to improve efficiency, then power-added efficiency increases for high PAR signals, but nonlinearity issues arise
Solution Approach 1:
The envelope tracking system changes the supply voltage parameter dynamically to maintain the amplifier in its linear region even at varying power levels. This parameter adjustment ensures that the amplifier operates efficiently while maintaining signal linearity, avoiding the nonlinearity problems associated with traditional high-efficiency amplifier topologies like Doherty.
Data Source
AI summary
This invention relates to a power amplifier device comprising an amplifier component (A) operable to receive an input signal (s;) and to provide an amplified output signal (so), according to a control signal (ctrl), an envelope tracking modulator (ET), providing the control signal (ctrl) according to a static voltage (V s) and a dynamic voltage (V D), a power supply (S) providing said static and dynamic voltages according to measurements performed by a power sensor (PS) on the amplified output signal, so that the static voltage (Vs) is determined as a mean value of the output signal (So) over a predetermined time duration.