Signal transmission device

A signal transmission device having a transmission buffer and a reception buffer,

• wherein the transmission buffer comprises:
• a differential circuit portion that is connected between a first potential and a second potential, and that outputs a first transmission signal to a first transmission terminal and a second transmission signal to a second transmission terminal, depending on a first input signal input via a first input terminal and a second input signal input via a second input terminal;
• a variable current source portion that supplies current to the differential circuit portion;
• a switch portion that switches between a conductive state and a disconnected state between the first transmission terminal and a fixed potential and between the second transmission terminal and the fixed potential;
• and
• a controller that controls the current supplied by the variable current source portion to the differential circuit portion, and that controls the operation of the switch portion, and
• wherein the reception buffer comprises:
• a first differential pair of a first conductivity type that is connected between a third potential and a fourth potential, that outputs a first received current in response to the first transmission signal input via a first received terminal, and that outputs a second received current in response to the second transmission signal input via a second received terminal;
• a second differential pair of a second conductivity type that is connected between the third potential and the fourth potential, that outputs a third received current in response to the first transmission signal, and that outputs a fourth received current in response to the second transmission signal;
• a first current mirror portion that flows a first mirror current obtained by current mirroring the first received current, between the third potential and a second output terminal, and that flows a second mirror current obtained by current mirroring the second received current, between the third potential and a first output terminal;
• and
• a second current mirror portion that flows a third mirror current obtained by current mirroring the third received current, between the second output terminal and the fourth potential, and that flows a fourth mirror current obtained by current mirroring the fourth received current, between the first output terminal and the fourth potential.