Patent ID: 7239814

Claim:
A driving apparatus of a light-emitting device for driving an light-emitting device to generate an optical pulse signal based on a transmission pulse signal comprising: a light-receiving device for receiving monitoring light emitted from the light-emitting device and outputting a light-receiving current signal; a current-to-voltage conversion section for converting the light-receiving current signal to a voltage signal; an AC coupling amplifier section for amplifying an AC component of the voltage signal output from the current-to-voltage conversion section and outputting an AC amplified signal; a differential output section for amplifying the AC amplified signal and outputting a positive phase voltage signal and a negative phase voltage signal; a first detecting circuit for detecting a peak value or a bottom value of the positive phase voltage signal and outputting a voltage depending on the peak value or the bottom value; a second detecting circuit for detecting a peak value or a bottom value of the negative phase voltage signal and outputting a voltage depending on the peak value or the bottom value of the negative phase voltage signal; a first reference voltage circuit for generating a first reference voltage; a first calculation section for adding an output voltage of the first detecting circuit and an output voltage of the second detecting circuit, and for outputting a voltage depending on a difference between a result of the adding and the first reference voltage; a first DC current output section for outputting a first DC current depending on a calculation result of the first calculation section; a pulse current output section for converting the first DC current to a pulse current depending on the transmission pulse signal so as to supply the pulse current to the light-emitting device; and a bias current output section for supplying a bias current to the light-emitting device.