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US 7,003,043 B2Granted
Replica driver mismatch correction using a variable offset comparator
AssigneeIntel Corporation
InventorsBryan K. Casper, Stephen R. Mooney, Aaron K. Martin
Life of this patent
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Abstract
A number of data symbols are driven into a transmission line while simultaneously driving the data symbols into another node. A difference between a signal level from the transmission line and a signal level from the other node while driving the symbols is determined. The difference is applied to a signal input of a variable offset comparator. One of a number of binary values (offset codes) are applied to an offset control input of the comparator, to adjust an implied, variable reference level of the comparator, prior to the comparator performing a comparison between the input signal and the implied reference level.
Claims21
A method comprising:
- (a) driving a plurality of data symbols into a transmission line while simultaneously driving the plurality of data symbols into another node;
- (b) determining a difference between a signal level from the transmission line and a signal level from the other node while performing (a), and applying the difference to a signal input of a comparator, the comparator having a substantially variable offset that is controllable to represent a variable reference level, an output of the comparator to provide a value that represents a comparison between a signal level at the comparator input and the variable reference level;
- and
- (c) applying one of a plurality of binary values to an offset control input of the comparator, to adjust the variable reference level prior to the comparator performing the comparison.
1 more element
A circuit comprising:
- a first driver having an output to be coupled to a transmission line;
- a second driver being a replica of the first driver, the first and second drivers having inputs being coupled to receive the same sequence of outgoing data symbols;
- a subtraction circuit having a first input to be coupled to the transmission line and a second input coupled to the output of the second driver;
- a comparator having an input coupled to an output of the subtraction circuit, the comparator having a substantially variable offset that is controllable to represent a variable reference level, an output of the comparator to provide a value that represents a comparison between a signal level at the comparator input and the variable reference level;
- and
- a control circuit having an output that is coupled to an offset control input of the comparator and is to provide a first binary value that corrects for one of a mismatch between the first and second drivers and a mismatch in the subtraction circuit.
3 more elements
A system comprising:
- a printed wiring board on which a bus is formed, an integrated circuit (IC) chip package installed on the board to communicate using the bus, the package having an IC chip that includes a logic function section and an I/O section as an interface between the logic function section and the bus, the I/O section having a first driver whose output is coupled to the bus, a second driver being a replica of the first driver, the first and second drivers having inputs being coupled to receive the same sequence of outgoing data symbols, a subtraction circuit having a first input coupled to the bus and a second input coupled to an output of the second driver, a comparator having an input coupled to an output of the subtraction circuit, the comparator having a substantially variable offset that is controllable to represent a variable reference level, an output of the comparator to provide a value that represents a comparison between a signal level at the comparator input and the variable reference level, and a control circuit having an output that is coupled to an offset control input of the comparator and is to provide a binary value.
A circuit comprising:
- means for transmitting a plurality of near end data symbols while allowing the simultaneous receipt of a plurality of far end data symbols;
- means for emulating the transmission of the plurality of near end data symbols;
- means for generating a difference between a signal level that represents one of the plurality of transmitted near end data symbols and a signal level that represents an emulation of said one of the plurality of transmitted near end data symbols;
- means for comparing the difference to an implied reference level without requiring a separate voltage input to receive the implied reference level;
- and
- means for adjusting the implied reference level to correct for one of a mismatch between the transmission and emulation means and a mismatch in the difference generation means.
3 more elements
Dependencies are inferred from the claim text.