Envelope Tracking Amplifier Delay Sensitivity via Voltage Range Control
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Solution Overview
Problem
Envelope tracking systems in mobile communication devices face reduced linearity and efficiency due to inherent bandwidth limitations, particularly with the advent of 5G-NR technology, which modulates RF signals at higher bandwidths, leading to temporal misalignment and degraded performance.
Innovation Solution
An envelope tracking amplifier circuit is designed with a voltage processing circuit to reduce the dynamic range of the ET modulated voltage and a control circuit to adjust the supply voltage, improving delay sensitivity and maintaining system-wide efficiency, especially in high-bandwidth scenarios by operating in both low- and high-bandwidth modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If envelope tracking system operates at higher bandwidth to support 5G-NR technology, then data rate and communication capability are improved, but linearity and efficiency deteriorate due to temporal misalignment
Solution Approach 1:
The system performs preliminary action by reducing the dynamic range of the ET modulated voltage before it causes temporal misalignment issues. The voltage processing circuit proactively limits the voltage swing to a reduced dynamic range that can be accurately tracked despite temporal delays, preventing linearity degradation before it occurs.
Solution Approach 2:
The system changes parameters by dynamically adjusting the dynamic range of the ET modulated voltage based on operating conditions. The voltage processing circuit modifies the voltage parameter to operate within a reduced dynamic range when temporal alignment is critical, while the control circuit adjusts supply voltage to maintain overall efficiency at different bandwidth operating points.
2Speed
If envelope tracking system operates at higher bandwidth to support 5G-NR technology, then data rate and communication capability are improved, but efficiency deteriorates due to temporal misalignment
Solution Approach 1:
The control circuit performs preliminary action by reducing the supply voltage to the PA before temporal misalignment can cause excessive power consumption. By proactively lowering the supply voltage when operating at high bandwidth, the system prevents efficiency degradation while maintaining the ability to support 5G-NR data rates.
Solution Approach 2:
The system changes the supply voltage parameter dynamically based on bandwidth and dynamic range requirements. The control circuit adjusts the supply voltage to optimal levels that maintain efficiency at different operating points, allowing the system to operate at high data rates while minimizing power consumption through adaptive parameter control.
3Reliability
If dynamic range of ET modulated voltage is reduced to improve delay sensitivity, then linearity is improved, but voltage utilization deteriorates
Solution Approach 1:
The control circuit implements feedback by continuously monitoring the dynamic range requirements and adjusting the supply voltage accordingly. This feedback mechanism ensures that the reduced dynamic range operation maintains optimal voltage utilization, compensating for the lower voltage swing through intelligent supply voltage control that responds to actual operating conditions.
4Use of energy by moving object
If supply voltage is reduced to maintain system-wide efficiency, then power consumption is improved, but amplification capability deteriorates
Solution Approach 1:
The system applies partial action by reducing the supply voltage only to the extent necessary to maintain efficiency, rather than uniformly lowering it. The control circuit determines the optimal reduction level that maintains sufficient amplification capability for the given operating conditions, applying just enough voltage reduction to improve efficiency without excessively compromising amplification performance.
Data Source
AI summary
An envelope tracking (ET) amplifier circuit is provided. The ET amplifier circuit includes an ET voltage circuit configured to generate an ET modulated voltage based on a supply voltage for amplifying a radio frequency (RF) signal. The ET modulated voltage corresponds to a time-variant voltage envelope, which can be misaligned from a time-variant signal envelope of the RF signal due to an inherent temporal delay in the ET amplifier circuit. A voltage processing circuit is provided in the ET amplifier circuit to reduce dynamic range of the ET modulated voltage to help improve delay sensitivity in the ET amplifier circuit. A control circuit is configured to reduce the supply voltage according to the dynamic range to help maintain system-wide efficiency of the ET amplifier circuit at a defined level. As such, it may be possible to improve delay sensitivity and maintain sufficient system-wide efficiency in the ET amplifier circuit.