| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical current amplifier circuit capable of easily changing setting of an amplification factor. SOLUTION: An NPN transistor Q11 and an NPN transistor Q12 comprise a differential circuit, and an output current of a variable current source CS11 flows to a resistor R11 connected between differential input terminals of the differential circuit. By adjusting the output current of the variable current source CS11, a control voltage to be applied between the differential input terminals is changed, and a current ratio of a collector current of the NPN transistor Q11 and a collector current of the NPN transistor Q12 is changed. A photodiode PD11 outputs a photo-diode output current Ipd corresponding to the intensity of received light in the state of applying a bias set by an output voltage of a constant voltage source V11 thereto. The photodiode output current Ipd becomes the collector current of the NPN transistor Q11. The collector current of the NPN transistor Q12 becomes an output current Iout of an optical current amplifier section 1. COPYRIGHT: (C)2006,JPO&NCIPI
|
