| 摘要 |
A pull-up output driver circuit includes a field effect transistor (FET) fabricated in a well region having a first conductivity type. The well region, in turn, is surrounded by a semiconductor region having a second conductivity type. The FET has a source connected to an output pad and a drain connected to a VCC voltage supply rail. The gate of the FET and the well region are connected to a driving circuit, and the semiconductor region is connected to the VCC voltage supply rail. A lateral bipolar transistor is formed by the drain, the source and the well region, and a vertical parasitic bipolar transistor is formed by the source, the semiconductor region and the well region. The driving circuit provides a signal (or signals) to the gate and well region to control the pull-up driver circuit. The FET turns on at a relatively low threshold voltage because the lateral bipolar transistor and the FET are turned on at substantially the same time.
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