Multi-Input Current Mirror Detector for PA Envelope Tracking
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Solution Overview
Problem
In high-frequency wireless communication systems like 5G-NR, maintaining the power supply voltage of power amplifiers at an optimal level to ensure efficiency is challenging due to sudden changes in signal amplitude, which can lead to inefficiencies and increased power consumption.
Innovation Solution
A current mode multi-input maximum signal detector is employed, which includes a maximum current detection circuit with multiple input current ports and a maximum current port. This circuit uses current mirror circuits to generate a maximum current corresponding to the largest input current, thereby controlling the supply voltage of the power amplifier to maintain efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power supply voltage is increased to maintain efficient operation during sudden signal amplitude changes, then the power amplifier efficiency is improved, but power consumption increases
Solution Approach 1:
The patent applies preliminary action by generating multiple delayed versions of the envelope signal before detecting the maximum. These delayed signals are created in advance to anticipate sudden amplitude changes, allowing the power supply voltage to be maintained at efficient levels without excessive power consumption. The delay circuits prepare multiple time-shifted envelope signals that are then processed to determine the maximum, enabling proactive voltage control rather than reactive adjustment.
Solution Approach 2:
The patent uses an intermediary approach by introducing a maximum signal detector that processes multiple delayed envelope signals to determine the maximum amplitude. This intermediary device (the detector circuit with delay elements) acts as a mediator between the envelope signal and the power supply voltage control, enabling accurate tracking of signal amplitude while avoiding direct coupling that would cause excessive power consumption during transitions.
2Use of energy by moving object
If the power supply voltage is reduced to save power, then power consumption decreases, but the power amplifier cannot maintain efficient operation during sudden signal changes
Solution Approach 1:
The delay circuits generate multiple advanced versions of the envelope signal, allowing the system to anticipate sudden amplitude changes before they occur. This preliminary action enables the power supply voltage to be maintained at efficient levels in advance, preventing the power amplifier from operating inefficiently while minimizing unnecessary power consumption during stable signal conditions.
Solution Approach 2:
The patent applies dynamics by creating multiple time-varying delayed versions of the envelope signal. These dynamic, time-shifted signals allow the system to adapt to changing signal conditions, enabling the power supply voltage to dynamically track the maximum amplitude while maintaining efficiency during sudden transitions and reducing power consumption during stable periods.
3Measurement precision
If multiple delayed envelope signals are processed to track maximum amplitude, then the accuracy of voltage control is improved, but the circuit complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the envelope signal processing into multiple separate delay circuits, each generating a time-shifted version of the original signal. This segmentation allows the maximum amplitude to be accurately tracked by comparing discrete delayed signals, improving measurement precision while keeping each individual circuit element relatively simple and manageable.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively keeps the power amplifier in an efficient operating range while reducing power consumption by accurately tracking the maximum signal amplitude and adjusting the supply voltage accordingly.
Implementation Method 1
The maximum current detection circuit includes multiple current mirror circuits, each controlled by one of the input currents. Each of the current mirror circuits includes outputs, each coupled to a respective one of the input current ports and the maximum current port.
Data Source
AI summary
A maximum current detection circuit with multiple input current ports and a maximum current port generates, on the maximum current port, a maximum current corresponding to the largest input current on one of the input current ports. The maximum current detection circuit includes multiple current mirror circuits, each controlled by one of the input currents. Each of the current mirror circuits includes outputs, each coupled to a respective one of the input current ports and the maximum current port. The current mirror circuit controlled by the largest input current becomes the dominant source for the input currents on each of the input current ports and also drives the maximum current on the maximum current port. The input currents may be single-ended or differential signals. The input currents may be respectively delayed signals of a windowing circuit in an envelope tracking circuit controlling a power amplifier of a wireless device.