Photoconductive Switch Module for High-Voltage Low-Resistance Control
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Solution Overview
Problem
Conventional power semiconductor device switches, such as MOSFETs, face limitations due to the un-modulated resistivity of the drift layer, leading to a tradeoff between specific on-state resistance and breakdown voltage, which is challenging for high-voltage operations.
Innovation Solution
A light-controlled switch module (LCSM) utilizing a photoconductive semiconductor switch (PCS) with a semiconductor body that generates carriers throughout the drift region when illuminated, decoupling the conductivity and breakdown relationship, and featuring thermal and electrical isolation of the light source from the switch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional power semiconductor device switches (MOSFET) are used, then the device structure is simple and easy to manufacture, but the tradeoff between specific on-state resistance and breakdown voltage limits high-voltage operations
Solution Approach 1:
The patent replaces the electrical gate control mechanism of conventional MOSFETs with an optical control mechanism using a light-controlled semiconductor switch. The light source emits photons that generate carriers in the drift region, turning the switch on without requiring high-voltage electrical biasing. This substitution eliminates the need for complex high-voltage gate drivers and enables high-voltage operations with improved reliability.
2Use of energy by moving object
If the light source is positioned close to the semiconductor body for efficient light coupling, then light utilization efficiency is improved, but thermal coupling increases causing unwanted heating
Solution Approach 1:
The patent segments the housing into distinct regions: a first region containing the light source and a second region containing the semiconductor body, separated by a thermally insulating barrier. This segmentation allows the light source to be positioned close to the semiconductor body for efficient light coupling while the thermal barrier prevents heat transfer, thus maintaining low thermal coupling between the two components.
Solution Approach 2:
The patent introduces a thermally insulating barrier as an intermediary element between the light source and the semiconductor body. This barrier is positioned between the first region (light source) and the second region (semiconductor body) to block thermal coupling while allowing light to pass through or around it, thus enabling efficient light utilization without unwanted heating.
3Reliability
If electrical isolation between light source and switch is implemented, then electrical interference is reduced, but additional isolation structures increase manufacturing complexity
Solution Approach 1:
The patent employs a housing structure that simultaneously serves multiple functions: it provides mechanical support for mounting the light source and semiconductor body, creates spatial separation between the first and second regions, and incorporates thermally insulating properties to block heat transfer. This multi-functional housing reduces the need for additional separate isolation structures, thereby maintaining ease of manufacture while achieving effective thermal and electrical isolation.
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 LCSM achieves lower resistance than conventional switches, reduces gate driver noise, and eliminates the need for high-voltage biasing, enabling improved switching times and high-voltage operations with reduced thermal conductivity between the light source and switch.
Implementation Method 1
Photoconductive semiconductor switches (PCSS) are opto-electrical devices made of semi-insulating semiconductor material that conduct electricity when they are turned on with light through optical excitation. In general, when photon energy is sufficient to raise electrons above a bandgap energy of a PCSS semiconductor material, free electrons are generated and electrical current flows through the PCSS.
Implementation Method 2
The housing includes a thermally insulating barrier between the first region and the second region to reduce heat transfer from the light source to the semiconductor body.
Data Source
AI summary
Light controlled switching modules are provide. In embodiments, a light controlled switching module includes: a housing; a light controlled semiconductor switch mounted to the housing, the light controlled semiconductor switch including a semiconductor body; at least one light source mounted to the housing in a spaced relationship from the light controlled semiconductor switch and positioned to direct light emitted from the at least one light source toward the semiconductor body; and first and second electrodes mounted to the housing and connected to the light controlled semiconductor switch, wherein the first and second electrodes are configured to have variable resistance between the first and the second electrode.