Dual-Gate Bidirectional Switch With Common Drift Region
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Solution Overview
Problem
Current bidirectional switches in source rectifiers, inverters, and converters suffer from high conduction losses due to forward diode voltage, which limits their efficiency and performance.
Innovation Solution
A monolithically integrated dual gate bidirectional switch is developed, which uses a common drift region for both blocking directions, eliminating the need for series-connected high-voltage devices and reducing conduction losses. This switch can be operated with active control of both gates using a single external signal or through passive control via a diode cascode configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If series connection of two high-voltage devices is used to achieve bidirectional blocking capability, then blocking capability is improved, but conduction losses increase due to forward diode voltage
Solution Approach 1:
The patent merges two high-voltage devices into a single integrated bidirectional switch structure. The common drift region is shared between both blocking directions, eliminating the need for series connection and the associated forward diode voltage losses. This consolidation maintains bidirectional blocking capability while reducing conduction losses.
Solution Approach 2:
The common drift region serves multiple functions: it provides blocking capability in both forward and reverse directions simultaneously. This multi-functional design eliminates the need for separate high-voltage devices for each blocking direction, thereby reducing overall conduction losses while maintaining full bidirectional blocking capability.
2Reliability
If series connection of two high-voltage devices is used to achieve bidirectional blocking capability, then blocking capability is improved, but device complexity increases
Solution Approach 1:
The patent combines two separate high-voltage devices into one integrated structure with a shared common drift region. This merging reduces device complexity by eliminating redundant components and interconnections while preserving the bidirectional blocking capability that would otherwise require series connection.
3Productivity
If active control of both gates is used to operate the bidirectional switch, then switching performance is improved, but control complexity increases
Solution Approach 1:
The patent introduces a control circuit that acts as an intermediary to manage the dual gate control requirements. This control circuit generates the appropriate gate signals based on a single external control input, thereby maintaining high switching performance while reducing the apparent control complexity for the user.
Solution Approach 2:
The bidirectional switch incorporates self-service control mechanisms where the device automatically manages its own gate control signals based on its operating state. This self-service capability reduces the external control signal requirements while maintaining optimal switching performance, as the device autonomously handles the complexity of dual gate coordination.
Data Source
Figure 1(A)~1(D)
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AI summary
A monolithically integrated bidirectional switch includes: an output terminal; a control terminal; a compound semiconductor substrate; a common drift region in the compound semiconductor substrate and in series between the input terminal and the output terminal; a first gate; and a second gate. The first gate is electrically connected to the control terminal and the second gate is electrically connected to the input terminal, or one of the first gate and the second gate is a normally-on gate and the other one of the first gate and the second gate is a normally-off gate. In either case, the monolithically integrated bidirectional switch is configured to conduct current in a single direction from the input terminal to the output terminal through the common drift region. A corresponding power electronic system that uses the monolithically integrated bidirectional switch is also described.