| 摘要 |
PROBLEM TO BE SOLVED: To elongate a battery life used as a system power supply by suppressing an incoming current generated when a display is started. SOLUTION: The voltage level control circuit 27 is installed in display equipment in which the system voltage VSYS fed from the power supply circuit 22 is boosted by the booster circuit 24, the boosted voltage V1 is fed to the liquid crystal voltage generation circuit 28 and the display is carried out by generating the voltage V2-V5 to drive the display. The output voltage (V1) of booster circuit 24 is lowered by feeding the reference voltage VREF to the voltage comparator circuit 25 through this voltage level control circuit 27 after it is lowered when the display is started. This enables to suppress an occurrence of the incoming current to a lesser degree, avoid an impact to the system power supply VSYS and lengthen the life of the battery 21 used as the system power supply.
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