| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a laser diode drive device that suppresses power consumption when a laser diode is driven and raises an output voltage of a power supply circuit at high speed. <P>SOLUTION: The laser diode drive device includes: a drive-current control circuit 10 that is connected to a cathode of a laser diode LD so as to control a current flowing in the LD; and a power supply circuit 20 that is connected to an anode of the LD so as to generate a variable output voltage applied to the LD. The power supply circuit 20 generates an initial value Vo_init of an output voltage which is equal to the sum of the maximum drive voltage, larger than an assumed drive voltage of the LD and a prescribed first reference voltage Vr1, obtians the then cathode voltage of the LD, and generates a voltage reduced from the initial value Vo_init of the output voltage so as to reduce the difference between the obatained cathode voltage and the first reference voltage Vr1. The first reference voltage Vr1 is the minimum cathode voltage necessary to supply a prescribed current to the LD by the drive-current control circuit 10. <P>COPYRIGHT: (C)2011,JPO&INPIT |
