Patent ID: 6424219
Filing Date: 2002-07-23
Classification: H03F

Abstract:
An operational amplifier, comprising:a first differential input stage circuit having a differential input terminal including a first positive input terminal and a first negative input terminal and a first output end, which is connected between a low-potential side power source and a high-potential power side to ensure an input range from a level at the low-potential side power source to a level at the high-potential side power source; a second differential input stage circuit having a differential input terminal including a second positive input terminal and a second negative input terminal and a second output end, which is connected between a low-potential side power source and a high-potential power side to ensure an input range from a level at the low-potential side power source to a level at the high-potential side power source; a first drive stage circuit having a first input end, a third output end, and a fourth output end, which is connected between the low potential side power source and the high potential side power source; a second drive stage circuit having a second input end, a fifth output end, and a sixth output end, which is connected between the low potential side power source and the high potential side power source; a first semiconductor device in which a first electrode is connected to a third output end of the first drive stage circuit and a second electrode is connected to the high-potential side power source, and a third electrode is connected to a first output terminal; a second semiconductor device in which a first electrode is connected to a fourth output end of the first drive stage circuit and a second electrode is connected to a middle-potential side power source, and a third electrode is connected to the first output terminal; a third semiconductor device in which a first electrode is connected to a fifth output end of the second drive stage circuit and a second electrode is connected to the middle-potential side power source, and a third electrode is connected to a second output terminal; a fourth semiconductor device in which a first electrode is connected to a sixth output end of the second drive stage circuit and a second electrode is connected to the low-potential side power source, and a third electrode is connected to the second output terminal; a first switching means having switches respectively connecting to the first output end of the first differential input stage circuit and the first input end of the first drive stage circuit and the second input end of the second drive stage circuit, in which the switches are operated in reverse with each other; and a second switching means having switches respectively connecting to the second output end of the second differential input stage circuit and the first input end of the first drive stage circuit and the second input end of the second drive stage circuit, in which the switches are operated in reverse with each other.