Bi-directional Transistor With By-pass Path
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Solution Overview
Problem
Existing bi-directional power MOSFET switches require two transistors in series, increasing costs and on-resistance, and lacking additional current flow paths.
Innovation Solution
A bi-directional transistor design that includes a first MOS transistor, a second switch transistor, and a by-pass switch, allowing for selective coupling of the body region to current carrying electrodes to enable bi-directional current conduction and voltage blocking, reducing the need for two transistors and enhancing current flow paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two power MOSFETs are connected in series to achieve bi-directional switching, then bidirectional voltage blocking capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines multiple functions (bidirectional switching, voltage blocking, and body diode functionality) into a single power MOSFET device. The body region is selectively coupled to different current carrying electrodes to enable the single transistor to perform functions that previously required two separate transistors connected in series.
Solution Approach 2:
The single power MOSFET is designed to perform multiple functions: it can block voltage in both directions, conduct current bidirectionally when needed, and provide body diode functionality. The selective coupling mechanism allows the same device structure to adapt to different operational requirements, making it a universal solution for bi-directional switching applications.
2Adaptability or versatility
If two power MOSFETs are connected in series to achieve bi-directional switching, then bidirectional voltage blocking capability is improved, but on-resistance increases
Solution Approach 1:
The patent merges the functionality of two series-connected transistors into a single transistor structure, thereby eliminating the cumulative on-resistance of two devices. The selective coupling of the body region enables this single transistor to achieve bidirectional switching with lower total on-resistance compared to the series configuration.
3Adaptability or versatility
If two power MOSFETs are connected in series to achieve bi-directional switching, then bidirectional voltage blocking capability is improved, but manufacturing cost increases
Solution Approach 1:
The patent consolidates what previously required two separate transistor devices into a single integrated power MOSFET structure. This merging reduces the number of discrete components needed, simplifies assembly, and lowers manufacturing costs while maintaining the bidirectional voltage blocking capability.
4Device complexity
If a single power MOSFET is used, then device complexity and cost are reduced, but bidirectional voltage blocking capability is lost
Solution Approach 1:
The patent introduces dynamic functionality through selective coupling of the body region to different current carrying electrodes based on operational requirements. This dynamic reconfiguration enables the single transistor to adapt its behavior for bidirectional voltage blocking, current conduction, or body diode operation, transforming a static single-device structure into a dynamically versatile component.
Data Source
AI summary
In one embodiment, a transistor is formed to have a first current flow path to selectively conduct current in both directions through the transistor and to have a second current flow path to selectively conduct current in one direction.