| 摘要 |
An op amp is arranged for low-voltage, rail-to-rail operation with a class AB output. The op amp includes a transconductance input stage, a folded cascode middle stage that includes a split cascode, a high-side driver, a low-side driver, a sampling circuit, and a split-cascode bias circuit. The split cascode includes two cascode transistors with their sources coupled to each other. Also, the sampling circuit that is arranged to sample the high-side driver current and the low-side sample current. The split cascode bias current is arranged to compare the sample current with a reference current, and to provide bias voltages to the gates of the two cascode transistors in the split cascode.
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