BUFFER AMPLIFIER, DRIVER IC, AND DISPLAY APPARATUS USING THAT DRIVER IC

摘要

[PROBLEMS] To provide a buffer circuit that is driven by a low voltage and performs a high speed operation. [MEANS FOR SOLVING PROBLEMS] A buffer circuit comprises a first comparator in which a MOS transistor having one of P and N channels between the input and output terminals of a buffer amplifier constitutes a comparing part in which a predetermined offset voltage is established for the comparison operation of this comparing part; and a switch circuit that is switched ON/OFF in response to an output signal from the first comparator. The buffer circuit flows a current from a power supply line through the switch circuit to the output terminal, thereby accelerating the rise of the output voltage of the buffer amplifier. The buffer circuit further comprises a second comparator in which a MOS transistor having the other of P and N channels constitutes a comparing part; and an operation limiting circuit that limits the comparison operation of the second comparator into a range of the dead band of the transistor constituting the comparing part of the first comparator. The switch circuit is switched ON/OFF in response to the output signal of the first comparator and that of the second comparator.