Differential signal generator circuit

A differential signal generator circuit comprising:

• a first amplifier for comparing an input signal with a threshold voltage and outputting differential signals;
• and
• a second amplifier for adjusting the threshold voltage in response to the input signal, wherein said second amplifier includes
• a first transistor and a second transistor forming a differential pair, each of said first and second transistors including a source, a drain, and a gate, the gate of said first transistor receiving the input signal, the drain and the gate of said second transistor being connected together,
• a third transistor and a fourth transistor forming a first current mirror, said third transistor being connected between the drain of said first transistor and a reference potential point, said fourth transistor being connected between the drain of said second transistor and said reference potential point,
• a current source connected to the sources of said first and second transistors, and
• an adjusting section for adjusting drain current of said first transistor in response to an externally applied current or voltage, whereby the threshold voltage is adjusted in response to drain voltage of said second transistor.