| 摘要 |
PROBLEM TO BE SOLVED: To provide a pickup circuit that utilizes a base-emitter voltage of a transistor(TR) so as to suppress occurrence of an undershoot thereby decreasing the settling time if an integrated circuit incorporating a light receiving element outputs a pulse signal. SOLUTION: The pickup circuit is provided with a push-pull circuit 25 that is connected between a power supply line and a ground line GND where an emitter of an NPN bipolar TR 23 and an emitter of a PNP bipolar TR 24 are connected to an output terminal 29, a photodiode 11 that converts an optical signal into a current, a feedback circuit 28 that feeds back an output signal of a pickup output terminal 29 corresponding to a current flowing to the photo diode 11 to an input of a differential circuit 17 to produce an input signal, the differential circuit 17 that amplifies this input signal, and a clip circuit 32 that clamps a base level of a bipolar TR 24 when the push-pull circuit 25 receives a differential output signal of the differential circuit 17 and outputs a pickup output signal. |
