| 摘要 |
For use in a semiconductor circuit device, a tri-state output buffer responds to a control signal generated in the semiconductor circuit device and a below-ground voltage level at an output terminal to prevent wasted drain and substrate current, and to reduce capacitance at the pull-up node driving the output terminal. The output buffer includes a power supply signal providing at least one voltage level with respect to common, an output terminal, a pull-up node, a pull-down node, a first circuit responding to the control signal by providing a first control voltage on the pull-up node, and a second circuit responding to the control signal by providing a second control voltage on the pull-down The output buffer is designed to respond to a voltage level on the output terminal being at a level substantially below common by preventing current flow from the power supply to the output terminal. |
