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:
Mar. 01, 2011
Filed:
Sep. 18, 2009
Shoji Kawahito, Hamamatsu, JP;
Kazutaka Honda, Hamamatsu, JP;
Yasuhide Shimizu, Isahaya, JP;
Kuniyuki Tani, Oogaki, JP;
Akira Kurauchi, Kawasaki, JP;
Koji Sushihara, Ikoma, JP;
Koichiro Mashiko, Takarazuka, JP;
Shoji Kawahito, Hamamatsu, JP;
Kazutaka Honda, Hamamatsu, JP;
Yasuhide Shimizu, Isahaya, JP;
Kuniyuki Tani, Oogaki, JP;
Akira Kurauchi, Kawasaki, JP;
Koji Sushihara, Ikoma, JP;
Koichiro Mashiko, Takarazuka, JP;
Semiconductor Technology Academic Research Center, Kanagawa, JP;
Abstract
A telescopic differential operational amplifier circuit for use in a pipelined A/D converter is provided with two auxiliary differential amplifiers connected to two cascode circuits, each including cascode-connected first to fourth transistors. During the sampling phase, first and second switches are turned on to apply a predetermined bias voltage to the gates of first and fourth transistors, and the input terminal of the differential operational amplifier circuit is set to a common mode voltage. During the hold phase, the first and second switches are turned off so that a voltage of each of the gates of the first and fourth transistors change to follow an input signal inputted via the input terminal with coupling capacitors operating as a level shifter of the input signal. Then the differential operational amplifier circuit performs push-pull operation operative only in a transconductance drive region, and is prevented from operating in a slewing region.