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:
Aug. 06, 1985
Filed:
Jan. 10, 1983
Ramanatha V Balakrishnan, San Jose, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
In a peripheral driver circuit a switching output transistor is operated from digital logic control and is provided with a shut off circuit which turns the output transistor off when its collector supply current exceeds its saturation current. A controlled base drive current is generated in a circuit that includes a scaled reference transistor that is operated at the same current density and the same collector voltage as the output transistor at its rated current. The reference transistor base current is amplified in a circuit having a current gain equal to the scaling between the reference and output transistors. Thus the base current applied to the output transistor is related to the driver rated current which ensures that saturation will occur up to at least the rated current and above which the shut off will be effective.