Differential output circuit

1 . A differential output circuit which performs data transmission by means of a differential current, comprising:

a first current source for outputting an electric current to the outside of the circuit;

a second current source for introducing an electric current from the outside of the circuit;

an output polarity switching circuit for switching the polarity of the differential current generated by the first and second current sources;

a voltage source for supplying a predetermined voltage; and

a resistor connected between a predetermined node and the voltage source, the predetermined node being interposed between the first and second current sources.

2 . The differential output circuit of claim 1 , wherein:

any one of the first and second current sources has a current value larger than that of the other current source; and

the other current source is connected to the voltage source.

3 . The differential output circuit of claim 2 , wherein:

the first current source has a current value larger than that of the second current source; and

the voltage source is a ground node.

4 . The differential output circuit of claim 2 , wherein:

the second current source has a current value larger than that of the first current source; and

the voltage source is a power supply node.

5 . The differential output circuit of claim 1 , wherein each of the first and second current sources is a variable current source.

6 . The differential output circuit of claim 1 , wherein the predetermined node is a connection point between any one of the first and second current sources and the output polarity switching circuit.

7 . The differential output circuit of claim 1 , wherein the predetermined node is an output terminal of the differential current.