Dual-Drive Power Amplifier With Gate-Source Phase Inversion
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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 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 below ground potential and increasing the output voltage swing without raising the supply voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If traditional power amplifier designs use common-source/common-emitter topology with increased supply voltage to improve output power and efficiency, then power added efficiency and output power are improved, but device reliability deteriorates due to high breakdown voltage stress and large voltage swings
Solution Approach 1:
The patent inverts the traditional approach by driving the source terminal with a signal that is 180 degrees out of phase with the gate terminal. This inversion allows the transistor to operate with negative drain-to-source voltage during parts of the cycle, effectively doubling the output voltage swing without increasing the supply voltage, thereby maintaining reliability while improving power efficiency
Solution Approach 2:
The patent changes the operating parameters by applying dual-drive signals to the gate and source terminals with opposite phases. This parameter change enables the transistor to utilize its full voltage range more effectively, achieving higher output power and efficiency without exceeding breakdown voltage limits, thus resolving the contradiction between power performance and device reliability
2Power
If traditional power amplifiers increase supply voltage to achieve higher output power and efficiency, then power added efficiency improves, but linearity deteriorates due to transistor knee voltage becoming a significant portion of supply voltage
Solution Approach 1:
By driving the source terminal with an inverted signal relative to the gate, the patent enables the transistor to operate in a more linear region. The negative voltage swing at the source counteracts the knee voltage effect, maintaining better linearity even at higher output power levels without requiring increased supply voltage
3Power
If complex design techniques such as load modulation and harmonically tuned loads are used to improve power amplifier performance, then certain performance metrics are improved, but device complexity increases
Solution Approach 1:
The dual-drive coupling network serves multiple functions simultaneously: it provides the out-of-phase drive signals to the source terminal, performs impedance transformation, and enables voltage swing enhancement. This multi-functionality achieves improved power efficiency without requiring separate complex circuits for each function, thus avoiding increased device complexity
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 configuration significantly enhances the power amplifier's efficiency, linearity, and output power while enabling the use of lower supply voltages, improving reliability and broadband performance.
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, while the second transmission line section is grounded at one end and coupled with the first transmission line section
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.