Patent ID: 6999687

Claim:
An optical receiving device, comprising: a photodiode having a first terminal coupled to a voltage source, and a second terminal, wherein when detecting an optical signal, the photodiode generates a current signal output from the second terminal; a transimpedance amplifier, whose input terminal is coupled to the second terminal, for converting the current signal to a voltage signal and outputting the voltage signal from the output terminal of the transimpedance amplifier; a coupling unit coupled to the second terminal and the input of the transimpedance amplifier; and a buffer unit coupled to the coupling unit and being a voltage follower comprising a transistor and a current source, coupled between the voltage source and a reference code in series, wherein a connection node of the voltage source and the reference code is coupled to the first terminal, and a gate of the transistor is coupled to the coupling unit; and wherein the coupling unit couples a first voltage-changing signal, occurring in the input terminal of the transimdepance amplifier with the current signal, to an input terminal of the buffer unit, and after receiving the first voltage-changing signal, the buffer unit outputs a second voltage-changing signal to the first terminal.