| 摘要 |
PROBLEM TO BE SOLVED: To provide a light-emitting element driving device for properly controlling the driving current of a light-emitting element, even if an operational amplifier constituting a circuit has an offset voltage. SOLUTION: A first peak holding circuit PH 1 holds the peak potential of a positive phase voltage signal outputted from a differential output amplifier A2, and a second peak holding circuit PH2 holds the peak potential of a reverse phase voltage signal outputted from the amplifier A2. An adding circuit ADD adds an output signal of the first peak holding circuit to the output signal of the second peak holding circuit. A differential input amplifier A3 amplifies a voltage of difference between a reference voltage Vr and an adding result voltage signal of the adding circuit, and outputs the amplified voltage. A current output circuit IPCONT outputs a direct current Io corresponding to the output voltage of the amplifier A3. A direct current switch circuit CUR-SW converts the direct current Io into a pulse current Ip, and supplies the converted current to a laser diode LD. COPYRIGHT: (C)2005,JPO&NCIPI
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