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. 06, 1994
Filed:
Feb. 17, 1994
Roelof F Wassenaar, Enschede, NL;
Johan H Huijsing, Schipluiden, NL;
Remco J Wiegerink, Borne, NL;
Ron Hogervorst, Voorschoten, NL;
John P Tero, Saratoga, CA (US);
Philips Electronics North America Corporation, New York, NY (US);
Abstract
A differential amplifier contains a pair of differential portions (10 and 12) that together provide representative signal amplification across the full amplifier power-supply voltage range. Each differential portion normally contains a pair of like-polarity differentially coupled FETs (Q1 and Q2, Q3 and Q4) that divide a tail current (I.sub.N, I.sub.P) into a pair of main currents (I.sub.1 and I.sub.2, I.sub.3 and I.sub.4). The two FET pairs are complementary. A square-root circuit (24) controls the tail currents in such a way that the sum of their square roots is largely constant. Consequently, the amplifier transconductance is largely constant.