| 摘要 |
PROBLEM TO BE SOLVED: To reduce power consumption at the time of a stand-by mode. SOLUTION: At a normal time, a bias is impressed on a circuit 42 of the prestage and a display device driving circuit 44 and they are made to be in operating states. The bias is interrupted in an emitter follower circuit 43 and it is in a nonoperating state and signals of R(G, B) and a COMMON signal from the prestage are inverted every 1 H to drive a liquid crystal display device as usually. At the time of the stand-by, the bias is interrupted and the circuit 42 of the prestage becomes to be in a nonoperating state. Besides, the emitter follower circuit 43 and the driving circuit 44 are in operating states. Since the voltage of VCC is applied to noninverted input terminals of operational amplifiers 9, 10 and the voltage of 1/2 of VCC is applied to inverted input terminals of them, the output of the COMMON and outputs of R, G, B become constants of 1/2 of VCC. As a result, since the potential difference is not generated in between both the output signals, the display screen of the liquid crystal display device becomes a white display.
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