Dual-Gate MOSFET Structure for Short-Circuit Current Limiting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor devices, such as power MOSFETs, are prone to short circuit events, which can lead to device failure and require improved robustness to prevent such occurrences.
Innovation Solution
The semiconductor device incorporates a control electrode configured to control a JFET formed by the body region, drift region, and second body region, allowing for independent control of the current through the device during short circuit events by reducing the drive voltage applied to the control electrode when a threshold current is exceeded.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single-gate MOSFET structure is used, then the device is simple in structure and easy to manufacture, but the device lacks robustness against short circuit events and cannot effectively limit current during failures
Solution Approach 1:
The transistor cell is segmented into multiple functional regions: a first gate electrode for switching control and a second gate electrode (control electrode) for current limiting control. The drift region is divided into a first drift region and a second drift region, with the second drift region forming a JFET structure controlled by the control electrode. This segmentation allows independent control of switching and current limiting functions, improving short circuit robustness without requiring a completely new device architecture.
Solution Approach 2:
The JFET structure formed by the first body region, first drift region, second drift region, and second body region acts as an intermediary current limiting mechanism. The control electrode serves as a mediator that can independently modulate the current through the JFET channel, providing an additional layer of protection against short circuits while maintaining the normal MOSFET switching operation through the first gate electrode.
2Reliability
If the drive voltage to the control electrode is reduced when threshold current is exceeded, then the current through the device is effectively limited during short circuits, but this requires additional monitoring and control circuitry
Solution Approach 1:
The system implements feedback control by monitoring the current through the transistor cells and adjusting the drive voltage applied to the control electrode accordingly. When the monitored current exceeds a threshold current, the feedback mechanism reduces the drive voltage to the control electrode, which in turn reduces the current through the JFET structure. This closed-loop feedback provides automatic current limiting protection without requiring external intervention or complex additional circuitry.
Solution Approach 2:
The semiconductor device performs self-protection by using its own control electrode and JFET structure to limit current during short circuit events. The device monitors its own current state and automatically adjusts the control electrode drive voltage to prevent damage, making the protection mechanism intrinsic to the device structure rather than requiring separate external protection circuits.
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
This design effectively limits the current through the device during short circuits, preventing failure by reducing the drive voltage applied to the control electrode, thereby minimizing damage and ensuring device reliability.
Implementation Method 1
a control electrode configured to provide a control signal for controlling a JFET formed by the first body region, the drift region, and the second body region
Implementation Method 2
a first gate electrode configured to provide a control signal for switching the transistor cell
Data Source
AI summary
A semiconductor device includes a semiconductor body having first and second opposing surfaces in a vertical direction, and transistor cells at least partly integrated in the semiconductor body. Each transistor cell includes first and second source regions, first and second body regions, a drift region separated from the respective source region by the corresponding body region, a first gate electrode, and a control electrode. The drift region is arranged between the first and the second body region in a horizontal direction that is perpendicular to the vertical direction and extends from the first surface into the semiconductor body in the vertical direction. The first gate electrode is configured to provide a control signal for switching the transistor cell. The control electrode is configured to provide a control signal for controlling a JFET formed by the first body region, the drift region, and the second body region.