| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a constant current circuit, along with a light-emitting diode driving device using the same, which can greatly expand an operation voltage range of an output terminal capable of outputting output current with a high accuracy and can enhance efficiency. <P>SOLUTION: The constant current circuit is configured to generate a fourth constant current i4 having the same current value with a first constant current i1, supply the fourth constant current to an NMOS transistor M16 of the same conductivity type with an NMOS transistor M1, set a drain voltage of the NMOS transistor M16 obtained by performing level shift of a voltage of a drain in which the fourth constant current i4 is input in the NMOS transistor M16 and inputting the voltage in a gate of the NMOS transistor M16, as a reference voltage, compare the reference voltage with a voltage of a section that connects an NMOS transistor M14 composing a voltage adjustment circuit 4 with a constant current source 2 with the use of an error amplifier circuit OP1, and output a signal Dout indicating results of the comparison. <P>COPYRIGHT: (C)2012,JPO&INPIT |
