Operational amplifier circuit

An operational amplifier circuit, comprising:

• first and second differential amplifier circuits, at least one of which operates in response to an input signal within a voltage range between a high potential power supply and a low potential power supply;
• a level shifter unit outputting a level shifted signal generated by level shifting of output signals of the first and second differential amplifier circuits;
• and
• an output circuit including complementary output transistors series being coupled between the high potential power supply and the low potential power supply and inputting the level shifted signal;
• wherein the level shifter unit outputs the level shifted voltage as a voltage obtained by a subtraction of threshold values of the complementary output transistors from a potential difference between the high potential power supply and the low potential power supply, and wherein the level shifter unit includes a voltage regulating unit regulating the level shifted voltage so as to cancel variations in the threshold values of the complementary output transistors.