Interface circuit adaptive to high speed and low voltage operation

An interface circuit for interfacing between a first integrated circuit on a transmitting side and a second integrated circuit on a receiving side over a line on a printed circuit board, comprising:

• an output circuit provided on said first integrated circuit on said transmitting side and including a current source for supplying a given current, and a switching circuit for intermittently cutting off said given current according to a binary signal and delivering said intermittently cut-off current as a current signal to said line;
• and
• an input circuit provided on said second integrated circuit on said receiving side and including a transimpedance circuit whose input impedance is matched with a characteristic impedance of said line and which converts said current signal into a voltage signal, and a comparison circuit for identifying said voltage signal relative to a given threshold voltage and reproducing said binary signal, said output circuit further including an additional current source for supplying a half of a current supplied by said current source and a transistor for delivering said half of a current to said line;
• and
• said input circuit further including an additional transimpedance circuit whose input impedance is matched with a characteristic impedance of said line and which converts said half of a current into a voltage, the converted voltage determining said given threshold voltage for said comparison circuit.