Patent ID: 7206329
Filing Date: 2007-04-17
Classification: B82Y,G06K,H01S

Abstract:
1. A driving system for a semiconductor laser device comprising: a semiconductor laser device for emitting light by energization; and a compensation circuit, connected to the semiconductor laser device in series, for compensating for an amount of current flowing through the semiconductor laser device; wherein the compensation circuit automatically compensates for a fluctuation in light output caused by a fluctuation in current vs. light output characteristics of the semiconductor laser device occurring due to a temperature change in a light emitting portion of the semiconductor laser device by use of a change in voltage vs. current characteristics of the semiconductor laser device occurring due to the temperature change in the light emitting unit of the semiconductor laser device, wherein the compensation circuit includes a negative resistance circuit comprising: first MOSFET device having a gate electrode connected to an input terminal and a substrate bias electrode connected to an output terminal; a second MOSFET device having a source electrode connected to the input terminal and a drain electrode connected to the output terminal, the drain electrode of the first MOSFET element being connected to the gate electrode of the second MOSFET device; and a resistance device having terminals, one of which is connected to the gate electrode of the second MOSFET and the other of which is connected to a power source voltage.