| 摘要 |
PURPOSE:To eliminate the need for a smoothing capacitor of a boosting driving circuit by specifying a relation between the rising and falling timing of a clock signal for boosting and the rising and falling timing of a liquid crystal driving AC signal. CONSTITUTION:Switches 5, 6 are changed over by a clock CL1b and a boosting capacitor CA is charged when this clock CL1b is at a high level. The drop of a low power source voltage VSS by the charging and discharging currents of a liquid crystal panel 4 does not arise if the timing period when a battery 1 and the capacitor CA are connected in series at the falling timing of the low level of the clock CL1b is so set as to attain the rising and falling timing of an alternating signal CL2b for liquid crystal driving and the boosting voltage is so set as to be held by the electrode capacity of the panel during the time of the parallel connection. Then, the need for the smoothing capacitor for preventing the drop of this voltage VSS is eliminated. |
