Field of the Invention
The present invention relates to a driving circuit for a light emitting element.
Description of the Related Art
Light emitting elements emit light due to a driving current that is supplied to them from a driving circuit. In laser diodes, which are an example of light emitting elements, light emission starts after a junction capacitance is charged with the driving current, and the desired light emission state is sustained by the driving current. Japanese Patent Laid-Open No. 5-243654 proposes a technique of supplying a preliminary current in advance to the laser diode, in order to shorten the time after the driving current is supplied until the laser diode starts to emit light (referred to as “rise time” below). The junction capacitance of the laser diode is charged by this preliminary current, so that the rise time of the laser diode is shortened.