Source follower circuit, laser driving apparatus, semiconductor laser apparatus, current-voltage convertion circuit, and light receiving circuit

摘要

Provided are a source follower circuit having a current source having its improved current characteristics, laser driving apparatus, semiconductor laser apparatus, current-voltage conversion circuit, and light receiving circuit. Each of the laser driving apparatus, semiconductor laser apparatus, current-voltage conversion circuit, and light receiving circuit comprises the source follower circuit. The source follower circuit 10 comprises a source follower stage 12 and a bias stage 14. The source follower stage has III-V compound semiconductor transistors 16, 18 and 20. The bias stage 14 has a first node 22 for providing a first bias voltage and a second node 24 for providing a second biasing voltage different from the first biasing voltage. The gate of transistor 16 is coupled to input 26 and a source thereof is coupled to output 28. The gate of transistor 18 is connected to the second node 24. The gate of transistor 20 is connected to the first node 24. The transistor 20 is arranged between the source of the transistor 16 and the drain of the transistor 18.