Signal line precharging tristate drive circuit.

摘要

The signal line precharging tristate driver circuit quickly and automatically precharges its off-chip signal line to the desired level just before it switches to its tristate or high impedance output condition. This is accomplished by providing precharge circuitry (10) coupled to the driver circuit (4 through 9) and responsive to the tristate control signal for overriding the normal input data signal and causing the driver circuit to commence charging the signal line. There is further provided tristate circuitry (20, 30, 31, 34, 35, 37, 38, 39) coupled to the driver circuit and responsive to its output voltage level for switching the driver circuit to the high impedance output condition when its output voltage and, hence, the signal line voltage reaches a desired predetermined value.