The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 29, 1987
Filed:
Dec. 27, 1985
Kaoru Imamura, Kawasaki, JP;
Kenichi Muramoto, Kawasaki, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
A protection circuit is provided for a planar transistor device. The protection circuit comprises a variable resistor device formed of a junction type field effect transistor. The resistor device is connected in series with the base of the planar transistor. The drain electrode of the J-FET is connected to the base of the planar transistor while the collector of the planar transistor is connected to the gate of the J-FET. Due to this interconnected scheme, base input resistance of the planar transistor is increased to reduce its base current when a high voltage is applied accidentally to the collector. The base current is not eliminated, however, and the device is protected but can still operate.