Differential Envelope Tracking Circuit for Wideband RF Power Dissipation
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Solution Overview
Problem
Existing RF power amplifier circuits in mobile communication devices face increased power dissipation issues due to the use of multiple antennas and power amplifiers, which compromises performance and user experience, especially in higher frequency spectrums like millimeter wave frequencies.
Innovation Solution
A wide-bandwidth envelope tracking (ET) circuit is implemented, utilizing a pair of tracker circuits to provide modulated voltages and currents to differential amplifier circuits, allowing for efficient amplification of RF signals up to 160 MHz without increasing power dissipation by reducing output impedance and enhancing slew rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple antennas and power amplifiers are employed to increase output power for higher data rates, then RF signal transmission capability is improved, but power dissipation increases
Solution Approach 1:
The patent divides the single power amplifier into multiple parallel amplifier circuits (first and second amplifier circuits), each handling a portion of the RF signal. This segmentation allows the system to achieve higher total output power while each individual amplifier operates at lower power levels, improving overall efficiency and reducing power dissipation per amplifier.
Solution Approach 2:
The patent implements dynamic supply voltage adjustment for each amplifier circuit based on the instantaneous power requirements of the RF signal. The supply voltage is modulated to match the signal envelope, allowing amplifiers to operate at optimal efficiency across varying power levels rather than running at constant high voltage, thereby reducing overall power dissipation.
2Loss of energy
If envelope tracking is used to improve PA efficiency, then power dissipation is reduced, but linearity and efficiency are impacted at millimeter wave frequencies
Solution Approach 1:
The patent segments the envelope tracking system into multiple independent tracker circuits, each associated with a specific amplifier circuit. This allows each tracker to independently manage the supply voltage for its corresponding amplifier, optimizing the envelope tracking performance for each channel and maintaining linearity and efficiency at millimeter wave frequencies while reducing overall power dissipation.
3Productivity
If wider bandwidth is supported for RF signals, then data rate capability is improved, but power dissipation increases
Solution Approach 1:
The patent divides the wide bandwidth RF signal processing into multiple parallel amplifier circuits, each handling a portion of the frequency spectrum or signal stream. This segmentation allows the system to support wider overall bandwidth for higher data rates while each individual amplifier operates efficiently at lower power levels, preventing the exponential power increase that would occur with a single wideband amplifier.
Data Source
AI summary
A wide-bandwidth envelope tracking (ET) circuit is provided. In examples discussed herein, the wide-bandwidth ET circuit is configured to enable a differential amplifier circuit(s) to amplify a radio frequency (RF) signal(s) modulated at a wide-bandwidth (e.g., up to 160 MHz) without increasing power dissipation. Specifically, the wide-bandwidth ET circuit employs a pair of tracker circuits to concurrently provide ET modulated voltages and currents (e.g., direct current and/or alternating current) to the differential amplifier circuit(s) for amplifying the RF signal(s). For example, each of the tracker circuits can be configured to provide one-half (½) of the total current required by the differential amplifier circuit(s). Accordingly, the tracker circuits can be implemented with smaller output stages. As a result, the tracker circuits can supply the ET modulated voltages at a higher slew rate and reduced output impedance, thus helping to improve power dissipation in the wide-bandwidth ET circuit.