Adjustable output driver circuit
AssigneeMicron Technology, Inc.
InventorBrent Keeth
Life of this patent
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Abstract
An adjustable integrated circuit output driver circuit is described which has a push-pull output circuit comprised of a pullup and pulldown transistor. A series of parallel transistors are connected to both the pullup and pulldown transistors. The gates of the parallel transistors are selectively controlled to adjust the driver current connected to a data bus line. Adjustable slew rate control circuits are described which are coupled to the pullup and pulldown transistors. Slew rate control circuitry and output control circuitry is provided to selectively adjust the driver circuit either during manufacture or after installation on a data bus. An alternate open-drain adjustable output driver circuit is also described.
Claims11
An integrated circuit output driver circuit comprising:
- a push-pull output circuit comprising a pullup output transistor having a drain connected to a data communication line, and a pulldown output transistor having a drain connected to the data communication line;
- a first adjustable circuit connected to a source of the pullup output transistor for adjusting a resistance between the source of the pullup output transistor and a first reference voltage;
- a second adjustable a resistance between the source of the pulldown output transistor and a second reference voltage;
- a pullup slew rate circuit connected to a gate of the pullup output transistor;
- and
- a pulldown slew rate circuit connected to a gate of the pulldown output transistor.
Dependencies are inferred from the claim text.