| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an offset cancel output circuit of a source driver for liquid crystal drive. <P>SOLUTION: An offset cancel output circuit includes an operational amplifier in which a reference voltage is applied to a non-inversion input end, an input capacitor and an output capacitor each having one end connected to an inversion input end, and a switch element circuit having a first field effect transistor connected between the inversion input end and an output end of the operational amplifier, for charging each of the input capacitor and the output capacitor with an offset voltage during a reset operation, and applying a gradation voltage to the other end of the input capacitor and connecting the other end of the output capacitor to the output end of the operational amplifier during a normal output operation. The switch element circuit applies a first potential equal to the reference voltage to a base of the first field effect transistor during the reset operation and the normal output operation, and applies a second potential different from the first potential instead of the first potential to the base to prevent a leak current flowing from a source/drain of the first field effect transistor to the base, when switching the gradation voltage during the normal output operation. <P>COPYRIGHT: (C)2012,JPO&INPIT |
