Overvoltage protector
Patent 4967256 Issued on October 30, 1990. Estimated Expiration Date: 
July 8, 2008. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
July 8, 2008. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesSemiconductor switching device Controlled breakover bidirectional semiconductor switch Patent #: 4797720 InventorsAssigneeApplicationNo. 216757 filed on 07/08/1988US Classes:257/112, With highly-doped breakdown diode trigger257/154, With resistive region connecting separate sections of device257/168, With means to increase breakdown voltage257/173, Device protection (e.g., from overvoltage)257/E29.337Thyristor diode (i.e., having only two terminals and no control electrode (e.g., Shockley diode, break-over diode)) (EPO)ExaminersPrimary: Hille, RolfAssistant: Fahmy, Wael Attorney, Agent or FirmForeign Patent References
International ClassesH01L 029/74H01L 029/72 H01L 029/90 AbstractAn overvoltage protector consists of a 4-layer diode having a buried region located adjacent to the central junction of the diode and of greater impurity concentration than the layer of the same conductivity type adjacent to it, so that the current through the diode preferentially flows through the buried region. The buried region is of smaller area than the emitter junction, so that avalanche multiplication in the buried region determines the breakover current of the diode. The holding current of the diode is set by parts of the second layer which perforate the first layer (emitter) thereby forming a resistive path in parallel with the emitter junction. A device for protecting against voltages of different polarities is decribed comprising two such diodes formed in parallel and connected in opposite senses with a common third layer. | |
