Patent ID: 8289079
Filing Date: 2012-10-16
Classification: G09G,H03F

Abstract:
1. An operational amplifier comprising: a control unit configured to switch an operation mode between first and second operation modes; an input section configured to receive input signals and supply one of the input signals as a first input signal to a first input node in said first operation mode and to a second input node in said second operation mode and the other of the input signals as a second input signal to said first input node in said second operation mode and to said second input node in said first operation mode; a first differential stage circuit section configured to differentially-amplify said first input signal supplied through said first input node in said first operation mode, and said second input signal supplied through said first input node in said second operation mode; a second differential stage circuit section configured to differentially-amplify said second input signal supplied through said second input node in said first operation mode, and said first input signal supplied through said second input node in said second operation mode; a first output drive stage circuit section configured to amplify said first input signal differentially-amplified by said first or second input differential stage circuit section to output as a first drive voltage; a second output drive stage circuit section configured to amplify said second input signal differentially-amplified by said first or second input differential stage circuit section to output as a second drive voltage; an output section configured to output through a first output node, said first drive voltage in said first operation mode and said second drive voltage in said second operation mode, and to output through a second output node, said second drive voltage in said first operation mode and said first drive voltage in said second operation mode; first and second power supplies configured to supply voltages in a first voltage range to said first differential stage circuit section and said first output drive stage circuit section in said first operation mode, and to supply voltages in said first voltage range to said second differential stage circuit section and said first output drive stage circuit section in said second operation mode; and third and fourth power supplies configured to supply voltages in a second voltage range which is different from said first voltage range, to said second differential stage circuit section and said second output drive stage circuit section in said first operation mode, and to supply voltages in said second voltage range in said first differential stage circuit section and said second output drive stage circuit section in said second operation mode, wherein said first or second drive voltage on said first output node is fed back to said first differential stage circuit section from one of said first and second output drive stage circuit sections, and wherein said first or second drive voltage on said second output node is fed back to said second differential stage circuit section from the other of said first and said second output drive stage circuit sections.