Patent ID: 8630324
Filing Date: 2014-01-14
Classification: G03G,H01S

Abstract:
1. A semiconductor laser drive device, comprising: a semiconductor-laser drive element to generate a drive current according to an input control signal to supply the drive current to a semiconductor laser; a control circuit to control the drive current by controlling the semiconductor-laser drive element; and a drive current detection circuit to detect a current value of the drive current supplied to the semiconductor laser and generate a digital control signal representing the detected digital value of the drive current to output, wherein the drive current detection circuit comprises: wherein the drive current detection circuit generates a drive-current detection signal indicating detection of the drive current for output when a predetermined relation between the value of the detection current and the value of the monitor current is established, and wherein the drive current detection circuit comprises a counter that increases or decreases the digital value of the digital control signal input to the D/A converter according to a clock signal to increase or decrease the value of the detection current output from the D/A converter.