| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a light emitting device drive circuit for low-voltage driving and low power consumption driving, which controls brightness of a light emitting device. <P>SOLUTION: A light emitting device 8 is connected to the output terminal 3 of a light emitting device drive circuit 20 constituting a charge pump circuit. When the oscillation frequency of an oscillator 12 is sufficiently high, switch elements 14, 15, 16, and 17 of the charge pump circuit are switched over, so that the voltage at both ends of a charged capacitor 11 is connected in series to a power source 7, which is applied to the light emitting device 8. When the oscillation frequency is low, the electric charge which is charged in the capacitor 11 at half-cycle of oscillation is discharged so that the voltage of the output terminal 3 falls, and the brightness of the light emitting device 8 is dropped compared with the case where the oscillation frequency is high. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
