| 摘要 |
PURPOSE:To attain the stable drive and to improve the transmission quality of a transmission optical signal by making two drive signals of a 3-state light emission control of a light emitting element as the same DC level and bringing an equivalent drive power at every drive signal into a desired value. CONSTITUTION:A light emitting element drive circuit is provided with two differential amplifiers 1, 2 and a reference voltage source 8 connected to input terminals 52, 62 of the amplifiers 1, 2. Further, the 1st drive signal and the 2nd drive signal are inputted respectively to other input terminals 51, 61 of the amplifiers 1, 2. Further, the positive logic output terminal 54 of the amplifier 1 and the negative logic output terminal 63 of the amplifier 2 are connected and the negative logic output terminal 53 of the amplifier 1 and the positive logic output terminal 64 of the amplifier 2 are connected. The light emitting element 3 is connected to one output terminal. Then the light emitting element 3 is driven by the 1st and 2nd drive signals and a 3-state output light is outputted from the light emitting element 3. |
