CURRENT-VOLTAGE CONVERTING AND AMPLIFYING CIRCUIT ADOPTING A LIMITER CIRCUIT BY A CURRENT DETECTION, ESPECIALLY RELATED TO FLOWING A LIMITER CURRENT BY DETECTING A CURRENT INSTEAD OF AN OUTPUT VOLTAGE

摘要

PURPOSE: A current-voltage converting and amplifying circuit adopting a limiter circuit by a current detection is provided to flow a limiter current for preventing saturation by detecting a current, thereby improving transient features of an RF waveform and an S/N(Signal to Noise) ratio. CONSTITUTION: A photo detection element(12) generates a current by receiving an optical signal. An amplifier(G1) receives the current, and amplifies the received current. An emitter follower(G2) is connected to an output of the amplifier(G1). An output buffer(G3) is connected to an output of the emitter follower(G2). A current detection limiter block(11) has an input end and an output end of a limiter current, is turned on when the current of the amplifier(G1) exceeds a predetermined threshold value, and flows the limiter current. A feedback resistor(Rf) is connected between an output of the amplifier(G1) and the photo detection element(12).