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:
Feb. 08, 1994
Filed:
Jan. 29, 1993
Mitsutoshi Sugawara, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
A current switching circuit includes a constant current source, a first transistor, a first resistor, second and third transistors, a selecting means, and a second resistor. The constant current source supplies a constant current. The first transistor is connected in series with the constant current source and has a base biased by one terminal of a power supply. The first resistor is connected between the first transistor and the other terminal of the power supply. The second and third transistors have collector currents as output currents and are rendered conductive by applying an output voltage of the first transistor to bases of the second and third transistors. The selecting means selectively applies the output voltage of the first transistor to the bases of the second and third transistors. The second resistor is connected between the other terminal of the power supply and a common connection point between emitters of the first and second transistors.