RF Power Amplifier Voltage Hold to Suppress APT Audible Noise
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Solution Overview
Problem
Electronic devices operating in Average Power Tracking (APT) mode experience audible noise due to the expansion and contraction of dielectric materials in capacitors, which generates vibrations and noise, especially when high voltages are applied and suspended.
Innovation Solution
Providing a driving voltage to the power amplifier even during periods when no RF signal is transmitted, specifically when events related to audible noise occur, to mitigate the noise generation by controlling the converter to maintain a stable voltage across the capacitor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If APT mode is used to control supply voltage according to RF signal transmission power, then power efficiency is improved, but audible noise is generated due to capacitor dielectric expansion and contraction
Solution Approach 1:
The patent applies periodic action by controlling the converter to provide driving voltage during specific periods (when no RF signal is transmitted and audible noise events occur) rather than continuously. This periodic voltage provision prevents capacitor dielectric expansion/contraction during critical periods, reducing audible noise while maintaining APT mode power efficiency during active transmission periods.
Solution Approach 2:
The patent uses preliminary action by detecting audible noise events in advance and proactively controlling the converter to provide driving voltage during the remaining period before noise occurs. This preventive approach stabilizes the capacitor voltage before expansion/contraction can generate audible noise, resolving the contradiction between power efficiency and noise reduction.
2Loss of energy
If driving voltage is suspended during non-transmission periods to save power, then energy consumption is reduced, but audible noise occurs due to voltage changes across the capacitor
Solution Approach 1:
The patent implements periodic action by selectively suspending driving voltage only during specific non-transmission periods when audible noise events are detected, rather than continuously suspending it. This selective periodic approach reduces energy consumption during safe periods while preventing audible noise during critical periods when voltage changes would cause dielectric expansion/contraction.
Solution Approach 2:
The patent applies feedback by monitoring for audible noise events and using this information to control the converter's driving voltage provision. The feedback mechanism detects when voltage changes would cause audible noise and adjusts the driving voltage accordingly, resolving the contradiction between energy savings and noise prevention through closed-loop control.
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 approach effectively reduces audible noise occurrences by stabilizing the voltage across the capacitor, thereby minimizing vibrations and noise levels during both transmission and non-transmission periods.
Implementation Method 1
At least one capacitor is connected between at least part of the at least one converter and the at least one power amplifier
Implementation Method 2
The expansion and contraction of the dielectric material may generate vibration
Implementation Method 3
at least one power amplifier configured to amplify the at least one RF signal and to output the at least one amplified RF signal
Data Source
AI summary
An electronic device may include: at least one communication processor, an RFIC, at least one power amplifier, and at least one converter and wherein the at least one communication processor is configured to: set a driving voltage, to be applied to a first power amplifier for amplifying a first RF signal provided from the RFIC among the at least one power amplifier, to be a first voltage, based on an APT mode, control at least part of the at least one converter to provide a first voltage, set based on the APT mode, to the first power amplifier during a transmission period of the first RF signal, and control at least part of the at least one converter to provide the first voltage to the first power amplifier during at least partial period of a remaining period in which no RF signal is transmitted, based on the occurrence of an event associated with audible noise.