Differential amplifier

A differential amplifier, comprising:

• a differential input circuit, adjusting a second current and a third current flowing into the differential input circuit according to a first input voltage, a second input voltage, and a first current;
• a first current source circuit, coupled between the differential input circuit and a ground terminal, and generating the first current according to a first reference voltage and a third reference voltage;
• a current-mirror circuit, coupled between an output terminal and the ground terminal, and generating a fifth current according to a fourth current and the third reference voltage;
• a second current source circuit, coupled between a power terminal and the output terminal, and generating a sixth current and a seventh current according to a second reference voltage, a first part of the sixth current flowing into the differential input circuit and forming the second current, a second part of the sixth current flowing into the output terminal, a first part of the seventh current flowing into the differential input circuit and forming the third current, a second part of the seventh current flowing into the current-mirror circuit and forming the fourth current;
• and
• an impedance circuit, coupled between the current-mirror circuit and the ground terminal.