Hybrid GaN HEMT Switch With Vertical Device Load Sharing
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Solution Overview
Problem
Current semiconductor switches, such as IGBTs and GaN HEMTs, face inefficiencies in low to medium load conditions due to high forward voltage drops and lack of integration with smart sensing and protection features, and parallel combinations with vertical devices are complex and costly.
Innovation Solution
A semiconductor switch combining a lateral GaN HEMT with a vertical high voltage device, like an IGBT or SiC MOSFET, using a single control terminal and an interface circuit to enable compatible driving voltages and integrate sensing and protection functions, allowing for monolithic integration of additional circuits for enhanced reliability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a parallel combination of lateral GaN HEMT and vertical device is used, then efficiency at low to medium loads is improved, but device complexity increases
Solution Approach 1:
The patent merges a lateral GaN HEMT with a vertical device (IGBT or SiC MOSFET) into a single integrated switch package. The lateral HEMT handles low to medium current loads with low forward voltage drop, while the vertical device handles high voltage blocking and high current loads. This combination resolves the contradiction by integrating two complementary device architectures that together cover the full operating range more efficiently than either device alone.
2Ease of operation
If a single control terminal is used to drive both HEMT and vertical device, then ease of operation is improved, but voltage compatibility complexity increases
Solution Approach 1:
The patent introduces an interface circuit as an intermediary between the single control terminal and the two parallel switches. This interface circuit receives a single control signal and automatically distributes appropriate gate drive voltages to both the HEMT and vertical device, handling voltage level translation and timing coordination. This resolves the contradiction by providing ease of operation through a single control terminal while managing the voltage compatibility complexity within the interface circuit rather than requiring external complexity.
3Reliability
If integrated sensing and protection features are added, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent integrates multiple functions into the interface circuit, including sensing, protection, and control signal distribution. The interface circuit monitors the operating state of both parallel switches and implements protection mechanisms, making it a multi-functional universal component. This resolves the contradiction by consolidating sensing and protection features within the existing interface circuit structure rather than adding separate dedicated circuits, thereby improving reliability while minimizing additional complexity.
Data Source
AI summary
A semiconductor switch comprising a first main terminal, a second main terminal, and a control terminal, the semiconductor switch including a III-nitride integrated circuit, the III-nitride integrated circuit including a high voltage HEMT, the high voltage HEMT comprising high voltage HEMT source terminal, a high voltage HEMT drain terminal, and a high voltage HEMT gate terminal, and at least part of an interface circuit. The semiconductor switch includes a high voltage transistor device that includes a transistor device first terminal, a transistor device second terminal, and a transistor device gate terminal, wherein the high voltage HEMT source terminal and the transistor device first terminal are operatively connected to the first main terminal, the high voltage HEMT drain terminal and the transistor device second terminal are operatively connected to the second main terminal. The high voltage HEMT gate terminal is operatively connected to the control terminal via the interface circuit.