| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce the power consumption of an output buffer which applies an analog voltage to a capacitive load on a display panel for image displaying. <P>SOLUTION: In a buffer for outputting an analog voltage Vout to be applied as a driving signal to a pixel capacity in the display area of an active matrix type liquid crystal display device, a CMOS circuit for generating the analog voltage is provided with four Pch transistors QP0 to QP3 interconnected in parallel, and four Nch transistors QN0 to QN3. During the charging of a pixel capacity, by controlling changeover switches SP1 to SP3, a bias current is reduced to lower driving capacity when large driving capacity becomes unnecessary after the start of the charging. During the discharging of charges stored in the pixel capacity, by controlling changeover switches SN1 to SN3, the bias current is reduced to lower driving efficiency when the large driving capacity becomes unnecessary after the start of the discharging. <P>COPYRIGHT: (C)2004,JPO |
