Dual-Mode APT Loop Filter for Fast Power Tracking and Low Ripple
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Solution Overview
Problem
Conventional average power tracking (APT) circuits in wireless communication devices face challenges in quickly changing transmission power levels, leading to frequent control signal changes that introduce unwanted ripples and ringing, which negatively impact noise performance and efficiency, especially in 5G-NR systems.
Innovation Solution
A dual-mode APT controller that rapidly adjusts the control voltage in a first mode to reach a target value and then switches to a second mode with reduced ringing, using variable resistance and capacitance in the loop filter, and optionally employs a pulse shaper circuit to facilitate faster changes, ensuring a clean control voltage during transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the size of capacitors and inductors in the control circuit is reduced to enable faster control signal changes, then the speed of control signal change is improved, but unwanted ripples and ringing are introduced in the control signal
Solution Approach 1:
The patent applies dynamics by making the loop filter parameters (resistance and capacitance values) changeable rather than fixed. The system dynamically switches between a first set of parameters for fast transient response and a second set for clean steady-state operation, allowing the control circuit to adapt its characteristics based on operational requirements.
Solution Approach 2:
The patent directly applies parameter changes by modifying resistance and capacitance values in the loop filter. A controller adjusts these parameters based on the operational state, switching between parameter sets to achieve either fast response or low ripple performance as needed.
2Stability of the object's composition
If conventional APT circuits use fixed loop filter parameters to maintain stable control voltage, then signal stability is improved, but the ability to quickly respond to frequent power level changes is degraded
Solution Approach 1:
The system transitions from a static loop filter design to a dynamic one where parameters can be adjusted in real-time. The controller monitors operational state and switches between parameter sets, enabling the loop filter to provide both fast response during transients and stable operation during steady-state conditions.
Solution Approach 2:
The patent implements parameter changes by varying resistance and capacitance values in the loop filter based on operational requirements. This allows the system to optimize the balance between response speed and stability for different operating conditions.
Data Source
AI summary
A dual-mode average power tracking (APT) controller operates in a first mode to move the control voltage quickly without concern for ripple or ringing. When this coarse adjustment takes the control voltage to within a desired margin of a target, the controller may switch to a second mode, where the APT controller more slowly approaches the target, but has reduced ringing or ripples. The mode is changed by changing resistance and capacitance values in a loop filter within the APT circuit. In a further aspect, a pulse shaper circuit may inject a pulse to force the control voltage to change more rapidly. By switching modes in this fashion, the control voltage may quickly reach a desired target, and then remain in the second mode during a transmission time slot such that the control voltage is clean throughout.