Dual-Drive Power Amplifier Source Terminal Swing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional power amplifiers in CMOS technology face limitations in efficiency, output power, linearity, and reliability due to low breakdown voltages and intrinsic device losses, especially at higher frequencies, which are exacerbated by stringent efficiency and linearity requirements in 5G New Radio applications.
Innovation Solution
A dual-drive power amplifier configuration where transistors are driven out-of-phase at the gate and source terminals using a dual-drive coupling network, allowing the source terminals to swing in-phase with the drain and reducing the knee voltage, thereby increasing output power and efficiency while enabling lower supply voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional power amplifier designs are used in highly scaled silicon processes with low supply voltages, then device reliability is improved, but power added efficiency and output power see diminishing returns due to transistor knee voltage becoming a significant portion of supply voltage
Solution Approach 1:
The invention segments the traditional single-drive approach into a dual-drive configuration, where the transistor is driven at both the gate and source terminals independently. This segmentation allows separate control of voltage swings at different terminals, enabling the source voltage to swing below ground potential while the gate receives the primary drive signal, thereby increasing output power without compromising reliability
Solution Approach 2:
The invention adds another dimension to the traditional gate-driven approach by introducing source terminal driving as an additional control dimension. The dual-drive coupling network creates a new degree of freedom in voltage control, allowing the source voltage to be modulated independently to extend the output voltage swing beyond what is possible with gate-driven operation alone
2Device complexity
If traditional power amplifier designs are used, then simplicity of design is maintained, but efficiency and linearity suffer due to intrinsic device large-signal losses at higher frequencies
Solution Approach 1:
The invention introduces a dual-drive coupling network as an intermediary component that mediates between the input signal and the transistor terminals. This coupling network distributes the drive signal to both gate and source terminals with appropriate phase and amplitude relationships, enabling efficiency improvements without requiring complex redesign of the entire amplifier architecture
3Reliability
If supply voltage is reduced to ensure device reliability, then reliability is improved, but power added efficiency deteriorates since knee voltage becomes a significant portion of supply voltage
Solution Approach 1:
The invention applies a counterweight approach by driving the source terminal with an out-of-phase signal that effectively counteracts the knee voltage drop. The source drive creates a voltage swing that opposes the knee voltage effect, allowing the transistor to operate more efficiently even at reduced supply voltages where knee voltage would normally dominate
4Adaptability or versatility
If array operations are performed, then system capability is enhanced, but antenna impedance mismatches and undesired large PA voltage swings occur resulting in efficiency degradation
Solution Approach 1:
The dual-drive coupling network provides a form of internal feedback mechanism where the source terminal drive is derived from and coupled to the gate drive signal. This feedback relationship allows the amplifier to automatically adjust the source voltage swing to compensate for impedance mismatches and voltage swing variations caused by array operations, maintaining efficiency across different operating conditions
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
The dual-drive power amplifier configuration significantly enhances output power, linearity, and efficiency, while allowing for reduced supply voltages, improving reliability and enabling broadband operation with low-loss inter-stage matching networks.
Implementation Method 1
a first transmission line section of a pair is configured to transmit an input signal Vin through to drive a gate of the opposite transistor
Implementation Method 2
the second transmission line section is grounded at one end and coupled with the first transmission line section such that a coupled portion αVin of the input signal Vin drives the source terminal
Data Source
AI summary
A dual-drive power amplifier (PA) where the PA core includes a differential pair of transistors M1 and M2 that are driven by a coupling network having two transmission-line couplers, where a first transmission line section of a coupler is configured to transmit an input signal Vin through to drive a gate of the opposite transistor, while the second transmission line section is grounded at one end and coupled with the first transmission line section such that a coupled portion αVin of the input signal Vin drives the source terminal of a corresponding transistor. The arrangement of the coupling network allows the source terminals to be driven below ground potential. Embodiments disclosed here further provide an input matching network, a driver, an inter-stage matching network, and an output network for practical implementation of the PA core.