Method and apparatus for limiting the slew rate of output drivers by selectively programming the threshold voltage of flash cells connected thereto
AssigneeIntel Corporation
InventorGregory D. Sabin
Life of this patent
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AssigneeIntel Corporation
InventorGregory D. Sabin
Estimating the term…
The output driver includes a plurality of transistor devices connected to an output line. In one arrangement, a separate flash-programmable element is connected to each of the plurality of transistor devices. Each of the separate flash elements receives the data signal along an input line and outputs the data signal if the flash cell is enabled (or not programmed) and outputs a constant voltage level, regardless of the data signal, if the flash element is not enabled. Hence, only those output transistors connected to flash elements that have been enabled are triggered by the output signal. Other transistors merely receive a constant voltage and are, therefore, not triggered regardless of the output signal. In another arrangement, the output driver is configured to forward output signals to all of the output transistors but the flash cells are programmed to adjust a time delay occurring prior to reception by the output transistors. This is achieved by setting the threshold voltage for the flash elements to differing values. The flash cells may be programmed to provide sequentially increasing time delays. Hence, the corresponding output transistors are activated sequentially resulting in a reduction in the increase of current drawn as a function of time, thereby reducing the total amount of voltage noise. In either arrangement, the various flash-programmable elements of the output drivers of the integrated circuit chip are programmed after fabrication of the chip.
In an output driver for outputting signals, subject to a current change slew rate, from an integrated circuit chip wherein the output driver includes a plurality of transistor devices connected to an output line, an improvement comprising:
An output driver having a programmable slew rate for use on an integrated circuit, said output driver comprising:
For use in an output driver of an integrated circuit wherein the output driver includes a data line for providing data, a plurality of output transistor devices each having an output connected to a common output pad, and a plurality of programmable flash devices with each device connected between the data line and an input of a respective one of the output transistor devices, a method comprising the steps of:
A method for selecting the slew rate of an output driver for use on an integrated circuit, said method comprising the steps of:
A computer system comprising:
Dependencies are inferred from the claim text.