| 摘要 |
<p>PURPOSE:To prevent damage to liquid crystal even when power failure is momentarily generated in a liquid crystal display device and to enable normal display by validating power supply after the lapse of prescribed time when the liquid crystal driving power supply is made invalid by the momentary power failure. CONSTITUTION:When the momentary power failure is generated, a power failure detection signal S2 outputted from a power supply part 21 is made valid and made invalid again later. At such a time, a clear signal S1 similarly outputted from the power supply part 21 is not made valid. Further, both a power source V0 for control and a power source V1 for driving the liquid crystal are not made invalid as well. In this case, when it is detected that the power failure detection signal S2 is made valid, a control part 22 instructs a timer monitor part 24 to start counting. The timer monitor part 24 counts time set in advance and after the counting is completed, it is informed of the control part 22. At that time, the control part 22 validates a liquid crystal driving power source V2. Therefore, even when the momentary power failure is generated, the normal display is enabled as long as a system is under an active state.</p> |
