GaN Cascode Transistor Gate Drive Circuit for Erroneous Turn-On Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
GaN-based semiconductor devices face challenges in realizing normally-off operation due to parasitic capacitance and erroneous turn-on issues, particularly in high-voltage power circuits where safety requires reliable normally-off operation.
Innovation Solution
A semiconductor device configuration that includes a normally-off transistor cascode-connected with a normally-on transistor, utilizing a gate drive circuit, capacitors, diodes, and a switch to manage gate potential and prevent erroneous turn-on, allowing for simple circuit design without the need for a negative voltage source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a normally-on GaN-based transistor is used to achieve high electron mobility and small device size, then productivity and device performance are improved, but reliability deteriorates because normally-off operation cannot be realized
Solution Approach 1:
The invention divides the transistor structure into two distinct transistors: a GaN-based normally-on transistor for high-performance switching and a Si-based normally-off transistor for safety control. This segmentation allows each transistor to fulfill its specific function optimally while together achieving both high performance and reliable normally-off operation.
Solution Approach 2:
The invention uses a composite structure combining GaN-based semiconductor material and Si-based semiconductor material in a cascode configuration. This composite approach leverages the superior electron mobility of GaN while incorporating the normally-off characteristic of Si transistors, resolving the contradiction between performance and safety.
2Reliability
If a mirror clamp circuit is added to suppress erroneous turn-on, then reliability is improved, but device complexity increases
Solution Approach 1:
The capacitor is charged during the transistor on-state and automatically discharges to clamp the gate potential when the transistor turns off. This self-service mechanism suppresses erroneous turn-on without requiring external control circuits or additional active components, maintaining circuit simplicity while improving reliability.
Solution Approach 2:
The capacitor is pre-charged to a specific voltage level during the transistor on-state before turn-off occurs. This preliminary charging action ensures that when the transistor turns off, the stored charge is immediately available to clamp the gate potential and prevent erroneous turn-on, eliminating the need for complex real-time control 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
The configuration effectively suppresses erroneous turn-on and ensures reliable normally-off operation of GaN-based semiconductor devices in high-voltage applications, maintaining circuit simplicity and safety.
Implementation Method 1
a first capacitor (30) having a first end and a second end, wherein the second end is electrically connected to the second gate
Implementation Method 2
a first diode (40) having a first anode electrically connected between the second end and the second gate, and a first cathode
Data Source
AI summary
A semiconductor device according to an embodiment includes: a normally-off transistor having a first source, a first drain, and a first gate; a normally-on transistor having a second source electrically connected to the first drain, a second drain, and a second gate; a first capacitor having a first end and a second end, wherein the second end is electrically connected to the second gate; a first diode having a first anode electrically connected between the second end and the second gate, and a first cathode; a gate drive circuit electrically connected to the first gate and the first end; and a switch having a third end and a fourth end, wherein the third end is electrically connected to the first end.