公开(公告)号：ITTO20000493D0

公开(公告)日：2000-05-26

申请号：ITTO20000493

申请日：2000-05-26

Applicant: ST MICROELECTRONICS SRL

Inventor： BASCHIROTTO ANDREA ,  CUSINATO PAOLO ,  MONTAGNA GIAMPIERO ,  CASTELLO RINALDO

IPC: H03F3/00 ,  H03F3/45

Abstract: A switched operational amplifier with fully differential topology, alternately switchable on and off, and a control circuit. The operational amplifier has a first differential output (4a) and a second differential output, and a control terminal. The control circuit includes a capacitive detecting network including a first capacitor and a second capacitor connected between the first and second differential outputs and a common-mode node, and a third capacitor connected between the common-mode node and ground in a first operative condition, and between the common-mode node and the supply voltage in a second operative condition. A control transistor is connected between the common-mode node and the control terminal of the operational amplifier and supplies a control current correlated to the voltage on the common-mode node. A switchable voltage source, connected to the common-mode node, supplies a desired voltage in a first operative condition, when the operational amplifier is off.