Patent ID: 7027027
Filing Date: 2006-04-11
Classification: G09G,H03F,H03K

Abstract:
1. A differential amplifying circuit, comprising: a first differential pair having first and second transistors of the same polarity, which outputs differential output signals in accordance with differential input signals supplied to gate terminals of said first and second transistors from differential output terminals; a second differential pair having third and fourth transistors having the same polarity as that of said first and second transistors with threshold voltages different from those of said first and second transistors, which outputs differential output signals in accordance with said differential input signals supplied to gate terminals of said third and fourth transistors from said differential output terminals; a bias supply part which supplies bias current to said first and second differential pairs; and a differential pair control part which controls whether or not to operate said second differential pair; wherein said bias supply part has only one current source which supplies current to said first and second differential pairs.