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:
Jul. 22, 1986
Filed:
Mar. 26, 1984
Suk K Kim, Brooklyn Park, MN (US);
Edward J Zimany, Jr, Morristown, NJ (US);
AT&T Bell Laboratories, Murray Hill, NJ (US);
Abstract
Current source circuitry consisting of a first n-channel field effect transistor (FET) and voltage generator circuitry coupled to the gate of the first FET. The voltage generator circuitry acts to control the current through the first FET such that it is essentially constant even with power supply, temperature, and many processing variations. The voltage generator circuitry consists of a second FET, a two input differential operational amplifier, a resistor, and an n-p-n transistor if the resistor has a positive temperature coefficient. A negative feedback path using the amplifier and the second FET ensures against current changes in the first and second FETs even if there are changes in one of the power supply levels and/or many semiconductor processing variations.