Multilevel driver for high speed chip-to-chip communications
First Claim
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1. An apparatus comprising:
- a plurality of driver slices arranged in parallel, each driver slice having a digital driver input and a slice output, each driver slice configured to generate a signal at a signal level determined by the digital driver input, and wherein each driver slice comprises;
a plurality of resistive elements having a first and a second end, the first end of each of the resistive elements being connected to the driver slice output; and
,for each resistive element, a voltage switching circuit connected to the second end of the resistive element, the voltage switching circuit configured to selectively couple the second end of the resistive element to a respective constant-voltage node in a group of at least two constant-voltage nodes, the voltage switching circuit being controlled by the digital driver input; and
,a common output node connected to (i) the plurality of driver slice outputs, (ii) a wire of a multi-wire bus.
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Abstract
Transmission line driver systems are described which are comprised of multiple paralleled driver elements. The paralleled structure allows efficient generation of multiple output signal levels with adjustable output amplitude, optionally including Finite Impulse Response signal shaping and skew pre-compensation.
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Citations
20 Claims
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1. An apparatus comprising:
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a plurality of driver slices arranged in parallel, each driver slice having a digital driver input and a slice output, each driver slice configured to generate a signal at a signal level determined by the digital driver input, and wherein each driver slice comprises; a plurality of resistive elements having a first and a second end, the first end of each of the resistive elements being connected to the driver slice output; and
,for each resistive element, a voltage switching circuit connected to the second end of the resistive element, the voltage switching circuit configured to selectively couple the second end of the resistive element to a respective constant-voltage node in a group of at least two constant-voltage nodes, the voltage switching circuit being controlled by the digital driver input; and
,a common output node connected to (i) the plurality of driver slice outputs, (ii) a wire of a multi-wire bus. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method comprising:
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obtaining an input stream of symbol values; providing the input stream of symbol values to a plurality of driver slices, each driver slice having a respective resistive element; generating a plurality of series of signal levels determined by the input stream of symbol values, each respective series of signal level values generated using a respective driver slice, wherein generating the respective series of signal levels comprises selectively coupling the respective resistive element to a constant-voltage node of a respective group of constant-voltage nodes, the constant-voltage node selected based on the input stream of symbol values; and forming an output symbol value based on a summation of the plurality of series of signal levels at a common output node. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification