Boost Converter Control for Envelope Tracking Headroom
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Solution Overview
Problem
Existing envelope tracking systems for power amplifiers face inefficiencies in determining when to enable a boost converter to generate a boosted supply voltage and setting the target voltage, leading to suboptimal DC power consumption and linear operation.
Innovation Solution
A method and apparatus for controlling the boost converter, where an enable generation block and a target generation block use the tracking supply voltage to determine when to enable the boost converter and set the target voltage, ensuring sufficient headroom for the power amplifier while minimizing unnecessary power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the boost converter is continuously enabled to generate boosted supply voltage, then the power amplifier can maintain sufficient headroom and linearity, but DC power consumption increases
Solution Approach 1:
The boost converter is dynamically controlled rather than continuously enabled. The control circuit monitors the power amplifier output and dynamically switches the boost converter on or off based on whether sufficient headroom is needed, optimizing the trade-off between linearity and power consumption in real-time
Solution Approach 2:
The boost converter operates in periodic on-off cycles rather than continuously. The control circuit periodically evaluates the need for boosted voltage and enables the converter only during periods when the power amplifier requires additional headroom to maintain linearity
2Use of energy by moving object
If the boost converter is enabled only when necessary, then DC power consumption is minimized, but the power amplifier may lack sufficient headroom to maintain linearity
Solution Approach 1:
The control circuit uses feedback from the power amplifier output to determine when the boost converter should be enabled. By monitoring the actual operating conditions and comparing them against thresholds, the system ensures the boost converter is activated only when necessary to maintain linearity while minimizing power consumption
3Reliability
If the target voltage is set high to ensure sufficient headroom, then the power amplifier can operate linearly, but the boost converter consumes more power
Solution Approach 1:
The target voltage of the boost converter is dynamically adjusted based on actual operating conditions rather than being fixed at a high value. The control circuit modifies the target voltage parameter to match the minimum necessary level for maintaining linearity, reducing unnecessary power consumption while ensuring adequate headroom 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 approach optimizes the use of the boost converter by enabling it only when necessary and setting the target voltage appropriately, thereby reducing DC power consumption and maintaining linear operation of the power amplifier.
Implementation Method 1
the supply voltage of the power amplifier may be generated using a separate linear amplifier that tracks the envelope of the power amplifier output. In certain implementations, the linear amplifier is itself coupled to an amplifier supply voltage generated by a boost converter, which is capable of generating a boosted supply voltage for the linear amplifier that exceeds the maximum supply voltage otherwise available to the system
Implementation Method 2
Envelope tracking is a technique for increasing the efficiency of power amplifiers. In an envelope tracking (ET) system, the supply voltage of a power amplifier is dynamically adjusted to keep the power amplifier operating with sufficient headroom to maintain linearity, while nevertheless minimizing DC power consumption
Data Source
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AI summary
Techniques for controlling boost converter operation in an envelope tracking (ET) system. In an aspect, an enable generation block is provided to generate an enable signal (Ven) for a boost converter (110), wherein the enable signal (Ven) is turned on in response to detecting that a sum of a first headroom voltage and an enable peak of a tracking supply voltage (Vamp) is greater than an amplifier supply voltage (VDD_Amp) of the ET system. The enable signal (Ven) may be turned on for a predetermined enable on duration. In another aspect, a target generation block is provided to generate a target voltage (Vtarget) for the boost converter (110), wherein the target voltage (Vtarget) comprises the sum of a second headroom voltage and a target peak of the tracking supply voltage (Vamp).