| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve efficiency while reducing a pattern area of a driving circuit for obtaining a driving current of a light emitting element. <P>SOLUTION: Positive power supply voltage Vdd is applied to an anode 26 of a white LED 25, and voltage -0.5 Vdd from a -0.5 Vdd generating circuit 40 is applied to a cathode 27 through an N-channel type MOS transistor M42. The -0.5 Vdd generating circuit 40 generates voltage -0.5 Vdd according to a clock ϕ from a clock generating circuit 30. Voltage of 1.5 Vdd is applied between the anode and cathode of the white LED 25 equivalently to the driving circuit. As a result of generally using the N-channel type MOS transistor in the -0.5 Vdd generating circuit 40, the pattern area of the circuit for obtaining the driving current of the LED 25 equivalent to the conventional one can be reduced. Further, parasitic capacitance is thereby reduced to improve the efficiency of the driving circuit. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
