OFFSET COMPENSATION CIRCUIT, DRIVE CIRCUIT WITH OFFSET-COMPENSATION FUNCTION USING THE SAME, AND LIQUID-CRYSTAL DISPLAY DEVICE

摘要

PPROBLEM TO BE SOLVED: To provide an offset compensation circuit in which an offset voltage can be accurately canceled. PSOLUTION: In a drive circuit 25 with the offset-compensation function, switches S1, S2-1, S2-2 are turned on to charge a capacitor 27-1 to an offset voltage VOF of a drive circuit 26, the switches S1, S2-1 are turned off and a switch S3-1 is turned on to charge a capacitor 27-2 to a voltage loss ▵V1 caused by a parasitic capacitor C0 of an input node N21 of the drive circuit 26. The switches S3-1, S2-2 are then turned off and switches S3-2, S4 are turned on. At such a time, a voltage loss ▵V2 caused by the parasitic capacitor C0 is also generated, and an output voltage VO becomes VI-▵V2. On the condition of CO=C1=C2, ▵V2 becomes 1/6 of ▵V1. Therefore, adverse influences by the parasitic capacitor C0 of the drive circuit 26 can be reduced. PCOPYRIGHT: (C)2005,JPO&NCIPI