| 摘要 |
PROBLEM TO BE SOLVED: To provide a light-emitting diode drive circuit having a small area in a semiconductor integrated circuit, and to provide a light-emitting diode system including the light-emitting diode drive circuit. SOLUTION: The light-emitting diode drive circuit includes a current drive circuit, a dynamic headroom controller, and a power supply circuit. The current drive circuit controls a current signal circulating to a light-emitting diode string in response to a first control signal including diode current information. The dynamic headroom controller supplies a third control signal to the power supply circuit by generating the third control signal changed in response to changes of the current signal circulating to the light-emitting diode string on the basis of a voltage signal of a first terminal of each light-emitting diode string and a second control signal including the light-emitting diode current information. Thus, the light-emitting diode drive circuit has a small area occupied in the semiconductor integrated circuit, and has high operating speed, and can be produced at inexpensive manufacturing cost. COPYRIGHT: (C)2011,JPO&INPIT |
