Patent ID: 7317358

Claim:
A differential amplifier circuit, comprising: a bias unit which generates a bias voltage; a first transistor which is connected between a first output node and a first source potential and whose conducting state is controlled by a control voltage; a second transistor which is connected between a second output node and the first source potential and whose conducting state is controlled by the control voltage; a plurality of resistors of essentially equal resistance values connected in series between the first and second output nodes; an operational amplifier, of which a positive phase input terminal is connected between the resistors, and a negative phase input terminal is supplied with a reference voltage to thereby output the control voltage; a third transistor which is connected between a first internal node and the first output node and has a control electrode supplied with a first input signal; a fourth transistor which is connected between a second internal node and the second output node and has a control electrode supplied with a second input signal; a resistance circuit which connects between the first and second internal nodes; a fifth transistor which is connected between a second source potential and the first internal node and causes a constant current corresponding to the bias voltage to flow; and a sixth transistor which is connected between the second source potential and the second internal node and causes a constant current corresponding to the bias voltage to flow.