Power Amplifier Delay Matching for Supply Signal Alignment
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Solution Overview
Problem
Inefficient alignment between the input signal and supply voltage in amplifiers leads to misalignment, resulting in reduced efficiency, particularly in RF signal amplification where the supply voltage is derived from the input signal, causing inefficiencies due to processing circuitry errors.
Innovation Solution
A method and apparatus that compare the output signal with distorted versions of the input signal, each associated with a different time delay value, to adjust the timing of either the input signal or the supply voltage to match the output signal, thereby compensating for misalignment without actual timing measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If envelope tracking power supply is used to improve efficiency, then energy efficiency is improved, but timing misalignment occurs between supply voltage and input signal
Solution Approach 1:
The system pre-generates multiple distorted versions of the input signal with different time delay values before comparison. This preliminary preparation of candidate signals with varying delays enables the selection process to identify the optimal timing alignment without requiring real-time measurement, thus resolving the timing misalignment issue while maintaining envelope tracking efficiency
Solution Approach 2:
The system compares the actual output signal with multiple pre-generated distorted versions and uses this comparison feedback to determine which time delay value produces the best match. This feedback mechanism automatically adjusts the timing alignment by selecting the optimal delay value, thereby resolving the contradiction between efficiency improvement and timing precision
2Manufacturing precision
If timing adjustment is made to improve signal alignment, then signal alignment is improved, but system complexity increases
Solution Approach 1:
Instead of implementing complex real-time timing measurement and adjustment mechanisms, the system preliminarily generates all possible distorted signal versions with different delays before comparison. This approach achieves precise signal alignment through pre-computation rather than complex real-time control, thereby improving alignment precision without proportionally increasing system complexity
Solution Approach 2:
The system creates multiple copies of the input signal with different distortion and delay characteristics. By comparing these pre-generated copies with the actual output, the system determines the optimal timing alignment. This copying approach simplifies the alignment process by avoiding complex measurement and adjustment circuitry, thus achieving precise alignment without excessive system complexity
Data Source
AI summary
There is described a method of controlling signal alignment in a power amplifier, comprising: receiving an input signal to be amplified; receiving a supply voltage for the power amplifier, the supply voltage being derived in dependence on the signal to be amplified; amplifying the input signal to produce an output signal; comparing the output signal with a plurality of distorted versions of the input signal, each distorted version of the input signal being associated with a different time delay value; and adjusting the timing of either the input signal or the supply voltage by an amount in dependence on a time delay value determined to be associated with a distorted version of the input signal which most closely matches the output signal.