Capacitive Voltage Divider for GaN HEMT Leakage Control
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Solution Overview
Problem
SiC and GaN power semiconductor devices suffer from leakage current, which reduces their performance, especially when connecting a voltage divider for sensing voltage to a gallium nitride-based high electron mobility transistor (HEMT), making it difficult to provide high-resistance elements to reduce leakage current and preventing voltage shift due to leakage current.
Innovation Solution
A semiconductor device design that uses capacitors instead of resistors in the voltage divider, coupled with a reset transistor to prevent voltage output from floating, thereby distributing voltage effectively and preventing voltage shift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-resistance elements are used to reduce leakage current in GaN-based HEMT voltage dividers, then leakage current is reduced, but it becomes difficult to provide such elements due to manufacturing constraints
Solution Approach 1:
The patent changes the fundamental parameter of the voltage division mechanism by replacing resistive division with capacitive division. Instead of using high-resistance elements that are difficult to manufacture in GaN HEMTs, the invention uses capacitors to achieve voltage division, thereby eliminating the manufacturing difficulty while maintaining the ability to reduce leakage current effects
Solution Approach 2:
The patent substitutes the electrical resistance-based voltage division mechanism with a capacitance-based mechanism. This replacement allows the system to achieve voltage division without relying on high-resistance elements that are problematic in GaN HEMT manufacturing, effectively replacing one physical principle (resistance) with another (capacitance) to solve the manufacturing constraint
2Ease of manufacture
If capacitors are used instead of resistors in the voltage divider, then manufacturing difficulty is reduced, but voltage output may float causing voltage shift
Solution Approach 1:
The patent introduces a reset transistor as an intermediary component to control the discharge path of the capacitors. This reset transistor acts as a mediator that prevents the voltage output from floating by providing a controlled discharge path to ground, thereby maintaining voltage stability while preserving the manufacturing advantages of the capacitive voltage divider
Solution Approach 2:
The reset transistor is controlled by a reset signal that monitors the voltage output state. When the voltage output tends to float, the feedback mechanism activates the reset transistor to discharge the capacitors and restore the voltage to a stable reference level, thus preventing voltage shift while maintaining the ease of manufacture
3Reliability
If a reset transistor is added to prevent voltage floating, then voltage stability is improved, but device complexity increases
Solution Approach 1:
The reset transistor serves multiple functions: it prevents voltage floating, provides a discharge path for the capacitors, and maintains voltage stability during transient conditions. By consolidating these multiple functions into a single component, the patent minimizes the increase in device complexity while achieving robust voltage stability
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 design effectively reduces leakage current and prevents voltage shift, ensuring stable voltage distribution in gallium nitride-based HEMTs by using capacitors and a reset transistor to reset the voltage output to 0 V or ground voltage.
Implementation Method 1
The voltage divider includes a plurality of capacitors, a voltage output circuit connected between the plurality of capacitors
Implementation Method 2
a reset transistor connected to the voltage output circuit... reset the voltage output to 0 V or ground voltage
Data Source
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AI summary
A semiconductor device includes a power semiconductor including a main transistor (H1); and, a voltage divider (D1) connected to the power semiconductor and including a plurality of capacitors (C1, C2), a voltage output circuit (Vvs) connected between the plurality of capacitors (C1, C2), and a reset transistor (T1) connected to the voltage output circuit (Vvs); wherein a gate electrode (155) of the main transistor (H1) is connected to a gate electrode (255) of the reset transistor (T1).