Patent ID: 7991032

Claim:
A laser driver, comprising: driving means having a first emitter follower for supplying a drive current to a laser, and a second emitter follower for discharging electric charges accumulated in the laser; drive current detecting means for detecting a magnitude of the drive current; reference current detecting means for receiving as its input a reference current as a reference for the drive current, and detecting a magnitude of the reference current; control voltage generating means for comparing a detection result obtained in said drive current detecting means and a detection result obtained in said reference current detecting means with each other, and generating a control voltage corresponding to the comparison result; and light emission controlling means for stopping the generation of the control voltage by said control voltage generating means and causing a given voltage corresponding to the magnitude of the reference current to be outputted to an input node of said first emitter follower to operate said first emitter follower for a first time period from start of a light emission time period of said laser, releasing the stop of the generation of the control voltage by said control voltage generating means and causing the control voltage thus generated to be outputted to said input node of said first emitter follower to operate said first emitter follower until end of the light emission time period of said laser, and operating said second emitter follower to discharge electric charges accumulated in said laser for a second time period after the end of the light emission time period of said laser.