| 摘要 |
PURPOSE:To prevent an optical output from varying owing to ambient temperature, and to make frequency characteristics to be good, by causing a predetermined current to flow through a light-emitting device according to the temperature to maintain the constant optical output, and by so controlling a current flowing through a field effect transistor as to be constant. CONSTITUTION:In a circuit for driving a light-emitting device 100 using a field effect transistor 200, a means 500 for controlling optical output, which is connected across the light-emitting device 100, causes a predetermined current to flow through the light emitting device 100 according to the ambient temperature to maintain a constant optical output at the light-emitting device 100, and so controls a current flowing the field effect transistor 200 as to be constant. As a result, the light-emitting device driving circuit can be obtained which maintains the constant optical output at the light-emitting device without being affected by the temperature, and has a good frequency characteristics. |
