Optically Triggered SiC Bipolar Power Switching Devices
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Solution Overview
Problem
Silicon carbide thyristors face challenges in large-scale manufacturing due to defects in wafers and designing optical drivers for large devices, which affects their performance and uniform light application.
Innovation Solution
The development of optically triggered wide bandgap bipolar power switching circuits and devices with galvanic isolation, using silicon carbide bipolar junction transistors and thyristors, allows for high noise immunity, fast switching, and remote control through fiber optics, addressing the manufacturing and design issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If large-scale silicon carbide thyristors are manufactured using entire wafers, then power handling capability is improved, but manufacturing defects are incorporated into the device which limits performance
Solution Approach 1:
The patent divides the large-scale power switching function into multiple smaller thyristor units that can be manufactured separately on silicon carbide wafers. Each smaller unit has a reduced area that can be fully covered by the optical beam, allowing defect-free manufacturing while maintaining high power handling capability through parallel operation of multiple units. This segmentation resolves the contradiction by enabling high power output without incorporating wafer defects into a single large device.
2Power
If the size of silicon thyristors is increased to handle higher power, then power handling capability is improved, but the design of optical driver becomes challenging due to difficulty in applying uniform light to large surface area
Solution Approach 1:
The patent segments the large switching function into multiple smaller thyristor units, each with a size that can be uniformly illuminated by the optical driver. The optical beam area is matched to the smaller unit size, ensuring uniform light distribution across each unit's surface. This segmentation makes the optical driver design feasible while maintaining high power handling capability through the combined operation of multiple units.
Solution Approach 2:
The patent transitions from a single large two-dimensional thyristor to multiple smaller two-dimensional units arranged in a three-dimensional configuration. This dimensional change allows the optical driver to effectively illuminate each unit while the overall system handles higher power through the collective operation of all units, resolving the contradiction between size and optical driver design.
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 solution provides high noise immunity, fast switch turn-on, high temperature, and high voltage operation with remote control capabilities, enhancing the performance and reliability of silicon carbide power switching devices.
Implementation Method 1
an optically triggered device configured to switch between a nonconductive state and a conductive state in response to light being applied thereto
Data Source
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AI summary
An electronic circuit includes a primarly wide bandgap bipolar power switching device configured to supply a load current in response to a control signal applied to a control terminal thereof, and a driver device configured to generate the control signal. At least one of the primary switching device or the driver device may include an optically triggered switching device. A discrete wide bandgap semiconductor device includes a primary bipolar device stage configured to switch between a conducting state and a nonconducting state upon application of a control current, and a bipolar driver stage configured to generate the control current and to supply the control current to the primary bipolar device stage. At least one of the primary bipolar device stage and the bipolar driver stage may include an optically triggered wide bandgap switching device.