GaN Power Amplifier Stages with Varying Breakdown Voltages
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Solution Overview
Problem
Existing gallium nitride (GaN) power amplifiers struggle to maximize both linearity and efficiency when fabricated into monolithic integrated circuits, as the gain of RF power amplifiers becomes non-linear with increasing input power, leading to distortion and reduced amplification.
Innovation Solution
A GaN power amplifier with multiple stages integrated into a monolithic integrated circuit, where at least one stage includes a first GaN transistor with a breakdown voltage no more than 75% of a second GaN transistor, operating at different supply voltages to enhance linearity and efficiency, with specific transistor configurations such as varying gate lengths, source-drain distances, and field plates to optimize performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple amplifier stages are fabricated on a monolithic integrated circuit using GaN technology, then device integration and compactness are improved, but maximizing both linearity and efficiency simultaneously remains unrealized
Solution Approach 1:
The patent applies local quality by fabricating different GaN transistor devices with different breakdown voltages (e.g., 45V and 90V) on the same monolithic integrated circuit. Each transistor is locally optimized with specific gate lengths, source-drain distances, and field plate configurations to operate at different supply voltages, enabling simultaneous optimization of linearity and efficiency in different amplifier stages while maintaining compact integration.
2Power
If amplifier stages operate at higher input power levels, then output power is improved, but gain becomes non-linear and distortion increases
Solution Approach 1:
The patent segments the amplification function into multiple amplifier stages, each with different breakdown voltage transistors operating at different supply voltages. This segmentation allows each stage to be optimized for specific operating conditions, with lower voltage transistors providing linear operation at lower power levels and higher voltage transistors handling higher power levels, thereby maintaining overall gain linearity across the full power range.
Solution Approach 2:
The patent changes the breakdown voltage parameter of GaN transistors by varying physical dimensions (gate length, source-drain distance) and structure (field plates). This parameter change enables transistors to operate at different supply voltages, allowing the amplifier to maintain linear operation across different input power levels by appropriately selecting which transistor operates at which power level.
3Reliability
If GaN transistors are configured with different breakdown voltages, then linear operation at different supply voltages is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple transistor types with different breakdown voltages onto a single monolithic integrated circuit substrate. This combining approach allows different transistor configurations (45V and 90V devices) to coexist and be controlled through unified biasing and matching networks, achieving diverse linear operation capabilities without proportionally increasing overall device complexity.
Data Source
AI summary
A gallium nitride (GaN) power amplifier having a plurality of amplifier stages integrated into a monolithic integrated circuit is disclosed. The plurality of amplifier stages is coupled together between a radio frequency signal input and a radio frequency signal output, wherein at least one of the plurality of amplifier stages includes a first GaN transistor that is configured to have a first breakdown voltage that is no more than 75% of a second breakdown voltage of a second GaN transistor included in a different one of the plurality of amplifier stages.