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US 6,639,434 B1Granted
Low voltage differential signaling systems and methods
AssigneeLattice Semiconductor Corporation
InventorArifur Rahman
Life of this patent
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Abstract
A low voltage differential signaling driver is disclosed that is capable of supporting many different LVDS standards or signal level requirements. The low voltage differential signaling driver has a programmable offset voltage and a programmable differential output voltage, which may be programmed independently.
Claims18
A driver comprising:
- a multiplexer adapted to select from a plurality of reference voltages;
- an amplifier, coupled to the multiplexer, adapted to receive the reference voltage selected by the multiplexer and set an offset voltage of the driver based on the reference voltage;
- a current source circuit, coupled to the amplifier, adapted to provide an output current for the driver;
- a plurality of transistors, coupled to the current source circuit and to a data line, adapted to route the output current to produce a positive differential output voltage or a negative differential output voltage based on a data value on the data line;
- and
- a current limiting circuit, coupled to the plurality of transistors, adapted to limit the output current to a value that provides a desired differential output voltage.
3 more elements
A driver comprising:
- means for selecting one of a plurality of offset voltages;
- means for providing a driver current and the selected offset voltage to generate a positive differential voltage or a negative differential voltage based on a data signal;
- and
- means for selecting one of a plurality of values for the driver current to provide a desired differential voltage level for the positive differential voltage and the negative differential voltage.
1 more element
A method of providing a plurality of low voltage differential signal levels from a single driver, the method comprising:
- programming a desired offset voltage based on a plurality of selectable reference voltages;
- providing a programmable current source and the offset voltage to generate a driver current;
- channeling the driver current to provide a positive differential output voltage or a negative differential output voltage based on a value of a data signal;
- and
- limiting the driver current to a specified value to provide a desired value for the positive differential output voltage and the negative differential output voltage.
2 more elements
Dependencies are inferred from the claim text.