GaN HEMT Series Switching Circuit for RF Impedance Matching
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Solution Overview
Problem
High-power RF matching networks in semiconductor fabrication face challenges with limited switching capabilities due to high voltage and current requirements, necessitating the development of efficient high voltage and high current switches for quick switching in RF matching networks.
Innovation Solution
The use of gallium nitride high-electron mobility transistors (GaN HEMTs) in switching circuits, configured in series with power sources to drive switches ON and OFF, enables efficient impedance matching in RF matching networks by reducing voltage stresses on active components and enhancing current handling capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high voltage and high current switches are used in RF matching networks, then power handling capability is improved, but switching speed is limited
Solution Approach 1:
The high voltage switch is divided into multiple series-connected transistors (first transistor and second transistor), each handling a portion of the total voltage. This segmentation allows each transistor to be optimized for faster switching while collectively handling the full high voltage, resolving the contradiction between power handling and switching speed.
Solution Approach 2:
The patent introduces a third dimension to the switching architecture by adding a series connection of transistors along the voltage dimension. This vertical stacking of transistors enables the system to handle high voltage through multiple devices in series, while each individual transistor maintains fast switching characteristics, thus achieving both high power handling and fast switching.
2Speed
If traditional switches are used in high power applications, then voltage handling is limited, but switching speed can be maintained
Solution Approach 1:
The high voltage requirement is segmented across multiple transistors connected in series, with each transistor handling a fraction of the total voltage. This allows the use of transistors with optimized switching characteristics rather than relying on a single high-voltage device that would sacrifice switching speed.
Solution Approach 2:
Multiple transistors are merged in series to create a composite switch that achieves both high voltage handling capability and fast switching speed. The combined structure leverages the strengths of individual transistors while overcoming their individual limitations through parallel connection in the voltage dimension.
3Power
If high voltage matching networks are used, then power transmission capability is improved, but voltage stresses on components increase
Solution Approach 1:
The total voltage stress is segmented and distributed across multiple series-connected transistors, with each transistor experiencing only a portion of the total voltage. This reduces the voltage stress on each individual component while maintaining the overall high power transmission capability of the matching network.
Solution Approach 2:
The series connection of transistors acts as a protective structure that beforehand distributes and cushions the voltage stress across multiple devices. This prevents any single transistor from experiencing the full brunt of high voltage stress, thereby improving reliability while maintaining power transmission capability.
Data Source
AI summary
In one embodiment, a switching circuit includes a first switch coupled to a first switch terminal, the first switch comprising at least one gallium nitride high-electron mobility transistor (GaN HEMT); a second switch coupled in series with the first switch and a second switch terminal, the second switching comprising a GaN HEMT; and at least one power source configured to provide power to the first switch and the second switch; wherein the second switch is configured to drive the first switch ON and OFF.