Monolithic Semiconductor Switch for High-Voltage Isolation
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Solution Overview
Problem
Existing semiconductor switches struggle to efficiently handle high operating voltages and rapid automatic shutdowns in the event of overcurrents, with complex structures and limited galvanic isolation, leading to reliability issues and unsuitable for high-voltage applications.
Innovation Solution
A monolithically integrated semiconductor switch comprising two field effect transistors with a dual thyristor configuration, where the source or emitter electrodes are short-circuited, and the drain or collector electrodes are connected to electrical connections, allowing for automatic shutdown without additional control electronics, enabling high blocking strengths and fast switching times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical circuit breakers are used to switch off overcurrent, then the current path can be safely interrupted with galvanic isolation, but the switching time becomes too long (over 100ms) and the structure becomes complex
Solution Approach 1:
The patent replaces the mechanical switching system with a semiconductor-based dual thyristor configuration. The mechanical moving parts (contacts, levers) are substituted by semiconductor devices that can switch off current paths electronically within microseconds, eliminating the 100ms+ switching delay while maintaining reliable current interruption through the inherent galvanic isolation of the semiconductor structure
Solution Approach 2:
The patent divides the single switching function into two separate thyristor devices operating in complementary fashion. The first thyristor handles the main current conduction while the second thyristor provides the isolation function. This segmentation allows each device to be optimized for its specific function, achieving both fast switching and reliable isolation without the complexity of mechanical systems
2Loss of time
If semiconductor switches (thyristors, GTOs, IGBTs) are used to achieve fast switching, then the switching time is reduced to microseconds, but galvanic isolation is lost and blocking currents flow in the mA range
Solution Approach 1:
The patent merges the functions of current conduction and galvanic isolation into a single integrated semiconductor device. The dual thyristor configuration combines the fast switching capability of semiconductor devices with the isolation function that was previously only available in mechanical breakers. The first thyristor conducts current while the second thyristor maintains the isolation barrier, achieving both microsecond switching and true galvanic isolation without blocking currents
Solution Approach 2:
The second thyristor acts as an intermediary device that maintains the isolation barrier while allowing the first thyristor to perform fast current interruption. This intermediary structure enables the fast switching of semiconductor devices to be transmitted across the isolation boundary, achieving microsecond response times while maintaining the galvanic isolation that prevents blocking currents in the control circuit
3Ease of operation
If IGBTs are used for switching, then the device can be turned off by control signal, but the on-state losses are significantly higher compared to thyristors
Solution Approach 1:
The patent changes the operating parameters of the thyristors to achieve controlled switching without the high on-state losses of IGBTs. By optimizing the doping profiles, layer thicknesses, and geometric dimensions of the dual thyristor structure, the device achieves low on-state voltage drops comparable to thyristors while enabling controlled turn-off through the complementary action of the two devices, eliminating the need for high-loss IGBT operation
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 solution provides a compact, low-maintenance semiconductor switch capable of handling high operating voltages up to 10kV or 200kV, with regenerative switch-off behavior, enhancing the reliability and efficiency of electrical network protection by eliminating the need for external control electronics.
Implementation Method 1
two field effect transistors, a source or emitter electrode of the first field effect transistor being short-circuited to a source or emitter electrode of the second field effect transistor
Data Source
Figure 1~4
Figure 5~6
Figure 7b~8b
AI summary
The present invention relates to a monolithically integrated semiconductor switch, in particular a power disconnect switch, with regenerative switching behavior. The semiconductor switch comprises two field-effect transistors, for example a p-JFET and an n-JFET, in monolithic integration. The source electrodes (S) of both JFETs and the well region of the n-JFET are short-circuited. Furthermore, the gate electrodes (G) of both JFETs and the drain electrode (D) of the p-JFET are short-circuited via the cathode (K). The well region of the p-JFET, however, is short-circuited to the anode (A). This results in a monolithically integrated semiconductor switch (1) that automatically switches off when a certain anode voltage or anode current is exceeded. The limit values for the anode voltage and the anode current can be determined by the component design.This makes it possible to achieve blocking strengths of up to 200kV with fast response.