| 摘要 |
PROBLEM TO BE SOLVED: To suppress increase in power consumption and expand the options for designs to a transistor for supplying a drive current. SOLUTION: In a drive circuit for driving a light-emitting element such as a laser diode LD, there are provided: a step-up circuit 11 for boosting an input voltage for supplying it to the light-emitting element; a light-receiving element such as a photo diode PD for monitoring the light from the light-emitting element; and a boosting control circuit 13 for controlling the boosting voltage of the step-up circuit, on the basis of the monitored quantity of the light receiving element. In a driving method of the light-emitting element for boosting the input voltage to supply it to the light-emitting element, the light from the light-emitting element is monitored, and the boosting voltage to the light-emitting element is controlled, on the basis of its monitored quantity. There is a case where a control circuit 12 for controlling the drive current flowing into the light emitting element is provided, on the basis of the monitored quantity of the light-receiving element. COPYRIGHT: (C)2010,JPO&INPIT
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