| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a light-emitting diode drive circuit capable of adjusting light emitting luminance in a light-emitting diode precisely by restraining an increase in a circuit scale, and capable of improving the rising and falling characteristics of the light-emitting diode drive current in gradation control. <P>SOLUTION: Current output sections 44<SB>1</SB>to 44<SB>m</SB>have: a first current mirror circuit that is composed with one portion of a reference current section and generates first and second currents based on a reference current; an upper transistor of a plurality of systems for allowing current proportional to a first current to flow corresponding to a switch that has been turned on in the switches of the plurality of systems; and a second current mirror circuit comprising the lower transistor of the plurality of systems cascadedly connected to the upper transistor of the plurality of systems. The first current mirror circuit has current varying circuits M38, M39, 42 varying the second current depending on when the reference current is less than a prescribed value and when the reference current is not less than the prescribed value. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
