Integrated MOV and Semiconductor Crowbar for Overvoltage Protection
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Solution Overview
Problem
Existing semiconductor devices for overvoltage protection, such as clamping devices and crowbar devices, suffer from slow response times, high leakage currents, and limited durability, making them inadequate for effectively managing transient overvoltage events.
Innovation Solution
An overvoltage protection device integrating a metal oxide varistor (MOV) with a semiconductor crowbar device, where the semiconductor crowbar component acts as a high impedance switch during an off-state, reducing leakage current and providing fast response and durable protection by clamping voltage to a low level when an overvoltage condition is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a clamping device is used for overvoltage protection, then voltage clamping is achieved, but the response time is slow and clamping voltage is high
Solution Approach 1:
The patent combines a semiconductor crowbar device and a metal oxide varistor (MOV) into a single integrated overvoltage protection device. The semiconductor layers (first through fourth) form a crowbar mechanism that rapidly responds to overvoltage conditions, while the MOV provides robust voltage clamping. This merger resolves the contradiction by achieving both fast response (from the semiconductor crowbar) and effective voltage clamping (from the MOV) simultaneously.
2Reliability
If a metal oxide varistor is used for overvoltage protection, then voltage clamping is achieved, but leakage current is high and self-heat dissipation accelerates aging
Solution Approach 1:
The integrated device merges the semiconductor crowbar structure with the MOV, where the semiconductor layers provide a low-leakage path during normal operation. The crowbar mechanism remains in high-impedance state during off-state, significantly reducing leakage current compared to a standalone MOV, while the MOV maintains its voltage clamping capability when triggered.
Solution Approach 2:
The patent changes the electrical parameters of the protection device by integrating the semiconductor crowbar, which alters the leakage current characteristics. The semiconductor structure modifies the overall device behavior, reducing the leakage current parameter while maintaining the clamping voltage parameter through the synergistic interaction between the crowbar and MOV components.
3Reliability
If a crowbar device is used for overvoltage protection, then voltage return to lower stage is achieved, but the device does not return to low leakage state without resetting
Solution Approach 1:
The patent merges the voltage restoration function of the crowbar device with the automatic reset capability inherent in the semiconductor structure. The semiconductor layers are designed to automatically transition from conducting to blocking state when the overvoltage condition subsides, eliminating the need for manual resetting while maintaining reliable voltage restoration.
4Speed
If a semiconductor crowbar device is used, then fast response is achieved, but clamping voltage may be high without proper integration
Solution Approach 1:
The patent merges the fast-response semiconductor crowbar mechanism with the robust voltage-clamping MOV structure. The semiconductor layers provide rapid detection and initiation of protection, while the MOV ensures the final clamping voltage remains at an appropriate level. This combination resolves the contradiction by achieving both fast response and controlled clamping voltage.
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 integrated device achieves low clamping voltage, low leakage, and fast response times, effectively protecting electronic equipment from overvoltage events while maintaining durability and accurate breakover voltage behavior.
Implementation Method 1
voltage may be clamped to a level characteristic of the particular clamping device
Implementation Method 2
when a certain voltage is reached
Data Source
Figure 1A~1B
Figure 2~3B
Figure 4A
AI summary
An overvoltage protection device (100) may include a metal oxide varistor (MOV) (102) having a first surface (114) and a second surface (116); a semiconductor substrate (202) having a first outer surface (126) and a second outer surface (128) and comprising a semiconductor crowbar device (104) comprising a plurality of semiconductor layers arranged in electrical series to one another, the semiconductor substrate (202) being disposed on a first side of the metal oxide varistor (102), a conductive region (124) disposed between the second surface (116) of the MOV (102) and the first outer surface (126) of the semiconductor substrate (202); a first electrical contact (120) disposed on the first surface (114) of the MOV (102); and a second electrical contact (122) disposed on the second outer surface (128) of the semiconductor substrate (202).