Envelope Signal Step Adjustment for ET Power Amplifiers
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Solution Overview
Problem
Conventional RF power amplifiers operating in linear mode are inefficient when handling RF waveforms with high crest factors, leading to increased power consumption and reduced efficiency due to the need to accommodate peak power levels while wasting power during lower signal periods.
Innovation Solution
An envelope tracking (ET) enabled power amplifier system that adjusts envelope signals step-by-step to match the required power levels, using a controller to compare amplitude differences and adjust output signals in smaller increments to optimize efficiency, combined with a DC-DC converter and LC filter circuit for voltage management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the amplifier operates in linear mode to accommodate high crest factor signals, then signal fidelity is improved, but power efficiency deteriorates
Solution Approach 1:
The patent applies dynamics by making the power supply voltage variable rather than fixed. The envelope tracking system dynamically adjusts the supply voltage to match the instantaneous envelope of the RF signal, allowing the amplifier to operate efficiently across varying power levels while maintaining linear operation for high crest factor signals.
Solution Approach 2:
The invention changes the parameter of power supply voltage from a constant value to a time-varying parameter that tracks the signal envelope. This parameter change enables the amplifier to adapt its operating point dynamically, improving efficiency without sacrificing signal fidelity in linear mode operation.
2Device complexity
If the amplifier maintains fixed power supply voltage to simplify design, then device complexity is reduced, but power efficiency deteriorates during low signal periods
Solution Approach 1:
The system transitions from a static power supply design to a dynamic envelope tracking system. The power supply voltage is modulated to follow the signal envelope, enabling efficiency improvements during low signal periods while maintaining adequate voltage during peaks through coordinated control.
3Power
If the amplifier increases power supply voltage to accommodate peak power levels, then peak power capability is improved, but power consumption increases during low signal periods
Solution Approach 1:
The invention changes the power supply voltage from a fixed peak-level value to a time-varying parameter that matches the signal envelope. This allows the amplifier to have sufficient voltage headroom for peak power delivery while reducing voltage (and thus power consumption) during low signal periods through envelope tracking.
Solution Approach 2:
The patent converts the previously harmful effect of high voltage during low signal periods (wasted power) into a benefit by dynamically reducing voltage to match actual signal requirements. The envelope tracking mechanism transforms what was a static inefficiency into a dynamic efficiency improvement.
Data Source
AI summary
The present disclosure provides a device and a method for adjusting envelope signals for use by an envelope tracking (ET) enabled power amplifier. The device comprises: a controller configured to calculate a difference between a first amplitude of a first envelope signal received at a first time instance and second amplitude of a second envelope signal received at a second time instance; compare the difference with a predetermined threshold; and adjust an output envelope signal corresponding to the first envelope signal in response to determining that the difference is greater than or equal to the predetermined threshold, such that the output envelope signal is adjusted step-by-step from the second envelope signal to the first envelope signal with each amplitude step being less than or equal to a predetermined amplitude step.