Patent ID: 8724082

Claim:
A semiconductor laser driver to drive at least one semiconductor laser, the semiconductor laser comprising: a control circuit to control a light emission intensity for the semiconductor laser based on a detected light emission intensity and on a predetermined light emission intensity setting value; a nonvolatile memory to store the multiple different predetermined magnifications, wherein the current magnification setting circuit amplifies the monitor current output from the photoelectric conversion element to the amplified current based on one of the multiple different predetermined magnifications stored in the nonvolatile memory; and a light detection circuit to detect a quantity of light emitted from the semiconductor laser as the detected light emission intensity and output the detected light emission intensity to the control circuit, the light detection circuit comprising: a photoelectric conversion clement to convert the quantity of light emitted from the semiconductor laser into an electrical current and output the converted electrical current as a monitor current; a current magnification setting circuit to amplify the monitor current output from the photoelectric conversion element to a predetermined amplified current at one of multiple different predetermined magnifications; and a detection resistor to convert the amplified current output from the current magnification setting circuit into a voltage and output the voltage as the detected light emission intensity.