Abstract:
The buffer has an output stage formed by two complementary MOS transistors connected so as to operate in phase opposition between the supply terminals and two driver stages having the input in common. Each driver stage has a first branch comprising a current-generator connected between the gate electrode of the transistor to be driven and a supply terminal and an electronic switch controlled by the input and connected between the same gate electrode and the other supply terminal, and a second branch which comprises, connected in series, a transistor connected as a diode and an electronic switch controlled by the output, and is arranged between the gate electrode of the transistor to be driven and a respective supply terminal. The buffer can control a load with a constant switching current, is simple in structure, and occupies a small area.
Abstract:
A digital system comprises a digital data processing unit, at least one output buffer connected to the processing unit to generate output signals in response to digital signals arriving from the processing unit and at least one user unit connect as output buffer load. With a view to assuring that the switching current of the output buffer can be set to different values, the output buffer comprises means for fixing the switching current to a value that is substantially constant and independent of the load and means for selectively setting the value of the switching current and the processing unit comprises means for storing a predetermined parameter; said means are connected to the selective setting means for setting the values of the switching current as functions of the predetermined parameter.