Envelope Tracking Amplifier Layout for Low Trace Inductance
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Solution Overview
Problem
Envelope tracking (ET) amplifier systems in mobile communication devices suffer from degraded efficiency and linearity due to trace inductance caused by long coupling distances between amplifier circuits, leading to increased power consumption and thermal dissipation, especially when RF signals are modulated above a certain bandwidth.
Innovation Solution
The ET amplifier apparatus co-locates the amplifier circuit with a local voltage amplifier circuit to reduce trace inductance, using a control circuit to activate the local voltage amplifier and provide a modulated voltage, thereby minimizing fluctuations in the modulated voltage and maintaining efficiency and linearity across varying modulation bandwidths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the amplifier circuit is located far from the voltage amplifier circuit, then the device complexity is reduced, but the trace inductance increases causing degraded efficiency and linearity
Solution Approach 1:
The system is divided into a remote amplifier circuit and a local voltage amplifier circuit, with the local circuit segmented to provide dedicated voltage amplification near the amplifier, reducing the impact of trace inductance while maintaining overall system simplicity
Solution Approach 2:
A local voltage amplifier circuit is introduced as an intermediary between the remote main voltage amplifier and the amplifier circuit, providing buffered voltage supply that compensates for trace inductance effects without requiring direct connection to the main amplifier
2Reliability
If the trace inductance is reduced by co-locating circuits, then efficiency and linearity are improved, but the device complexity increases
Solution Approach 1:
The local voltage amplifier circuit provides localized voltage amplification specifically where needed near the amplifier circuit, creating a region of high voltage stability that compensates for trace inductance without requiring global system redesign
Solution Approach 2:
The local voltage amplifier circuit is nested within the amplifier apparatus, integrating multiple functions (voltage amplification, buffering, and local power supply) into a compact unit that reduces trace inductance while maintaining manageable device complexity
3Reliability
If the local voltage amplifier circuit is activated for high bandwidth modulation, then the efficiency is maintained, but the device complexity increases
Solution Approach 1:
The local voltage amplifier circuit is designed to be dynamically activated based on modulation bandwidth requirements, allowing the system to adapt its complexity level to match the operational demands without permanently increasing device complexity
Solution Approach 2:
The control circuit changes operational parameters by activating the local voltage amplifier circuit specifically when high bandwidth modulation is detected, adjusting the system's voltage supply characteristics to maintain efficiency only when needed
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
This configuration reduces trace inductance to below a defined threshold, improving the efficiency and linearity of the amplifier circuit, even when RF signals are modulated at higher bandwidths, thereby enhancing overall performance and reducing power consumption.
Implementation Method 1
trace inductance between the amplifier circuit and the local voltage amplifier circuit
Implementation Method 2
an amplifier circuit configured to amplify an RF signal based on a modulated voltage
Data Source
AI summary
An envelope tracking (ET) amplifier apparatus is provided. The ET amplifier apparatus includes an amplifier circuit configured to amplify a radio frequency (RF) signal based on a modulated voltage. In examples discussed herein, the amplifier circuit is co-located with a local voltage amplifier circuit configured to supply the modulated voltage such that a trace inductance between the amplifier circuit and the local voltage amplifier circuit can be reduced to below a defined threshold. By co-locating the amplifier circuit with the local voltage amplifier circuit to reduce a coupling distance between the amplifier circuit and the local voltage amplifier circuit and thus the trace inductance associated with the coupling distance, it may be possible to reduce degradation in the modulated voltage. As a result, it may be possible to improve efficiency and maintain linearity in the amplifier circuit, particularly when the RF signal is modulated at a higher modulation bandwidth.