SOURCE FOLLOWER CIRCUIT, LASER DRIVING DEVICE, SEMICONDUCTOR LASER DEVICE, CURRENT/VOLTAGE CONVERTING CIRCUIT AND PHOTODETECTOR CIRCUIT

摘要

PROBLEM TO BE SOLVED: To provide a source follower circuit having a current source improved in constant current characteristics, a laser driving device provided with this circuit, a semiconductor laser device, a current/voltage converting circuit and a photodetector circuit. ;SOLUTION: The source follower circuit 10 is provided with a source follower stage 12 and a bias stage 14. The source follower stage has field-effect transistors 16, 18 and 20. The bias stage 14 has a first node for providing a first bias voltage and a second node for providing a second bias voltage different from the first bias voltage. The gate of the transistor 16 is connected to an input 26 and the source is connected to an output 28. The gate of the transistor 18 is connected to the second node. The gate of the transistor 20 is connected to the first node. The transistor 20 is provided between the source of the transistor 16 and the drain of the transistor 18.;COPYRIGHT: (C)2001,JPO