| 摘要 |
PROBLEM TO BE SOLVED: To provide an operational amplifier for expanding an output voltage range with low power consumption without increasing the size of a circuit, and to provide a drive circuit and an electrooptical device. SOLUTION: The operational amplifier 100 includes a differential amplifier 110 that has a pair of n-type differential transistors DIF1 where an input voltage Vin and an output voltage Vout are supplied to a gate, and an n-type current source transistor CS1 for generating the sum of a drain current in transistors QN1, QN2 of the pair of differential transistors DIF1, and that amplifies the difference between the input voltage and the output one; and a p-type drive transistor DQP1 that is provided at a high-potential power supply side, and allows the gate to be controlled based on the voltage of an output node in the differential amplifier 110 for generating a drain voltage as the output voltage Vout. In the current source transistor CS1, the potential of an impurity layer in which the channel region is formed is set independently of the potential of the impurity layer in which the channel regions of other transistors are formed. COPYRIGHT: (C)2007,JPO&INPIT
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