Two-Wire AC Switch Using GaN Bidirectional Element
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Solution Overview
Problem
Conventional two-wire AC switches using silicon-based semiconductor devices face limitations in reducing on-resistance, leading to high conduction losses and restrictions on power consumption, making them unsuitable for loads exceeding 200 W.
Innovation Solution
A two-wire AC switch utilizing a bidirectional switch element made of group-III nitride semiconductors, specifically AlGaN/GaN hetero-junction field-effect transistors with two gate electrodes, which reduces on-resistance and enhances breakdown voltage characteristics, allowing for efficient bi-directional current control and reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a silicon-based TRIAC is used as a bidirectional switch element, then the device can control AC power supply to loads, but the on-resistance is high causing large conduction losses and heat generation
Solution Approach 1:
The patent changes the fundamental material parameter from silicon to group-III nitride semiconductor, which has inherently lower on-resistance and higher breakdown voltage characteristics. This material parameter change enables the bidirectional switch element to achieve low conduction loss while maintaining reliable switching capability for high-power loads exceeding 200W.
Solution Approach 2:
The patent employs composite material structure by combining group-III nitride semiconductor with aluminum gallium nitride (AlGaN) to form hetero-junction field-effect transistors. This composite structure leverages the superior electrical properties of nitride semiconductors to simultaneously reduce on-resistance and enhance breakdown voltage, resolving the contradiction between energy loss and switching reliability.
2Loss of energy
If the bidirectional switch element is made of silicon, then the device structure is simple, but the material limit prevents further reduction of on-resistance
Solution Approach 1:
The patent fundamentally changes the material parameter from silicon to group-III nitride semiconductor, breaking through the material limit that prevents further on-resistance reduction in silicon-based devices. This parameter change enables continued optimization of conduction loss without being constrained by silicon's inherent physical limitations.
3Temperature
If conventional TRIAC switches are used, then the device can operate bidirectionally, but heat generation is excessive for high-power applications
Solution Approach 1:
The patent changes the material parameter to group-III nitride semiconductor, which has superior thermal and electrical properties. This enables the device to handle high-power loads exceeding 200W with significantly reduced heat generation, resolving the contradiction between temperature control and productivity enhancement.
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 use of group-III nitride semiconductor-based bidirectional switch elements in two-wire AC switches significantly lowers on-resistance, enabling stable switching operations for larger loads and reducing heat generation, thus overcoming the limitations of conventional switches.
Implementation Method 1
Spontaneous polarization and piezoelectric polarization cause electric charges on a hetero-junction interface between aluminum gallium nitride (AlGaN) and gallium nitride (GaN)
Implementation Method 2
Spontaneous polarization and piezoelectric polarization cause electric charges on a hetero-junction interface between aluminum gallium nitride (AlGaN) and gallium nitride (GaN)
Implementation Method 3
a bidirectional switch element causing passing current to flow bi-directionally and selecting whether to flow or block the passing current
Data Source
AI summary
A two-wire AC switch suppressing heat from a bidirectional switch element inside the switch is provided. The two-wire AC switch 100a connected between an AC power supply 101 and a load 102 includes: a bidirectional switch element 103 which flows passing current bi-directionally, selects whether to flow or block the current, is connected in series with the AC power supply 101 and the load 102 to form a closed-loop circuit, and is made of a group-III nitride semiconductor; a full-wave rectifier 104 performing full-wave rectification on power supplied from the AC power supply 101; a power supply circuit 105 smoothing a voltage after the full-wave rectification to generate DC power; a first gate drive circuit 107 and a second gate drive circuit 108 each outputting a control signal to the bidirectional switch element 103; and a control circuit 106 controlling the first and second gate drive circuits 107 and 108.