HEMT Clamping Circuit for Semiconductor Gate Protection
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Solution Overview
Problem
Power devices, particularly high voltage power devices, are susceptible to destruction by high voltage spikes that cause transient high currents, leading to potential breakdown.
Innovation Solution
A semiconductor device comprising a transistor and a clamping circuit, where the clamping circuit, comprising a D-HEMT and an E-HEMT, clamps the control signal and gate current to a predetermined level, limiting the maximum control signal and gate current to prevent device breakdown during high voltage spikes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a power device is designed to handle large power signals, then the power handling capability is improved, but the device becomes vulnerable to high voltage spikes causing breakdown
Solution Approach 1:
A clamping circuit is introduced as an intermediary protective element between the input signal and the power device (transistor). The clamping circuit includes a D-HEMT and E-HEMT configured to limit voltage spikes before they reach the main transistor, thereby protecting the power device while allowing it to maintain its high power handling capability
Solution Approach 2:
The clamping circuit is designed to activate before high voltage spikes can damage the power device. By setting the clamping voltage threshold below the breakdown voltage of the transistor, the circuit provides beforehand protection by clamping excessive voltages to safe levels, preventing transient high currents that would otherwise cause device failure
2Reliability
If a clamping circuit is added to protect the transistor, then the device reliability is improved, but the circuit complexity increases
Solution Approach 1:
The D-HEMT and E-HEMT in the clamping circuit serve multiple functions: they act as voltage clamping elements to protect the transistor, while also functioning as active devices that can be controlled to provide protection only when needed. This multi-functionality reduces the need for additional dedicated protective components, thereby limiting the increase in circuit complexity
Solution Approach 2:
The invention utilizes the threshold voltage characteristics of D-HEMT and E-HEMT devices to achieve voltage clamping. By exploiting the inherent electrical parameters of these transistors (threshold voltage, transconductance), the clamping function is achieved without requiring complex passive components or multiple discrete elements, thus maintaining relatively simple circuit architecture
Data Source
AI summary
A device includes a first transistor having a first source terminal, a first drain terminal, and a first gate terminal; and a second transistor having a second source terminal, a second drain terminal, and a second gate terminal. The second source terminal is coupled to the first gate terminal and the first source terminal is coupled to the second gate terminal. The first transistor has a first threshold voltage, and the second transistor has a second threshold voltage different from the first threshold voltage.