OFFSET CONTROL CIRCUIT FOR AN OPTICAL DISK, AN INTEGRATED CIRCUIT, AN OPTICAL DISK DEVICE, AND AN OFFSET CONTROL METHOD, ESPECIALLY CONCERNED IN ENABLING A CONTROL VOLTAGE CONTROLLER TO GENERATE AN ERROR SIGNAL FOR SERVO CONTROLLING OF AN OPTICAL PICKUP AS WELL AS TO CONTROL AN OFFSET

摘要

PURPOSE: An offset control circuit for an optical disk, an IC, an optical disk device, and an offset control method are provided to enable a control voltage controller to control an offset based on a digital signal produced from an A/D converter, without forming individual A/D converters for generating an error signal and controlling the offset, thereby reducing power consumption. CONSTITUTION: Differential operational amplifiers(OPe,OPf) for offset controlling are applied with an output signal of an optical pickup in one-sided input terminals, while being applied with a control voltage on other-sided input terminals. An A/D converter(AD) outputs a digital signal based on output signals of the differential operational amplifiers(OPe,OPf). A control voltage controller(LO) varies the control voltage applied to the differential operational amplifiers(OPe,OPf) based on the digital signal, to remove an offset.