Bidirectional Switch With Common Drift Region for Lower Conduction Loss
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Solution Overview
Problem
Current source rectifiers, inverters, and converters with bidirectional blocking capability suffer from high conduction losses due to forward diode voltage, as they require active control of only one blocking direction.
Innovation Solution
A monolithically integrated bidirectional switch with a compound semiconductor substrate and two gates, where one gate is normally-on and the other is normally-off, or both are symmetrical, allowing for active control to block voltages of both polarities and conduct current in a single direction through a common drift region, reducing conduction losses by eliminating the need for separate drift regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate drift regions are used for bidirectional blocking, then blocking capability is improved, but conduction losses increase
Solution Approach 1:
The patent merges two separate drift regions into a single shared drift region that serves both blocking directions. The bidirectional switch uses one common drift region between the input and output terminals, eliminating the need for separate drift regions for each blocking direction, thereby reducing conduction losses while maintaining bidirectional blocking capability.
Solution Approach 2:
The common drift region performs multiple functions: it blocks voltages of both polarities in reverse direction while conducting current in forward direction. This universal drift region replaces what would traditionally require two separate drift regions, achieving multi-functionality with a single structure.
2Device complexity
If forward diode voltage is used for blocking, then device simplicity is improved, but conduction losses increase
Solution Approach 1:
The patent replaces passive diode blocking with active transistor-based blocking using gates. Instead of relying on forward diode voltage for blocking, the invention uses electric field control through gates to achieve blocking, substituting a passive mechanical/electrical system with an active controlled system that has lower losses.
3Adaptability or versatility
If active control of one blocking direction is implemented, then device functionality is improved, but device complexity increases
Solution Approach 1:
The patent employs asymmetric gate structures where one gate (first gate) is connected to a control terminal for active control, while the other gate (second gate) is connected to the input terminal. This asymmetric configuration enables active control of blocking in one direction while the other direction is passively controlled, achieving versatile functionality without excessive complexity.
Data Source
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.