Termination of transmission lines using simultaneously enabled pull-up and pull-down circuits

An information handling system, comprising:

• at least two transmission lines each having a characteristic impedance, each of said transmission lines having a first end, each of said first ends being commonly connected to each other first end, and a second end;
• a plurality of drivers equaling the number of transmission lines in said plurality of transmission lines, each driver coupled to a second end of a different one of said transmission lines, each driver comprising a pull-down circuit having a pull-down resistance and a pull-up circuit having a pull-up resistance, the parallel combination of said pull-up resistance with said pull-down resistance matching the characteristic impedance of said transmission lines such that an output resistance of each of said drivers is approximately equal to the characteristic impedance of the transmission lines;
• and
• at least one receiver circuit coupled to a second end of one of said transmission lines.

An information handling system, comprising:

• at least three transmission lines each having a characteristic impedance, each of said transmission lines having a first end, each of said first ends being commonly connected to each other first end, and a second end;
• a plurality of drivers, each driver individually coupled to a second end of one of said transmission lines, each driver comprising a pull-down circuit having a pull-down resistance and a pull-up circuit having a pull-up resistance, the parallel combination of said pull-up resistance with said pull-down resistance matching the characteristic impedance of said transmission lines;
• at least one receiver circuit coupled to a second end of one of said transmission lines;
• and
• at least one on-chip terminator, each of said on-chip terminators comprising a pull-down circuit having a pull-down resistance and a pull-up circuit having a pull-up resistance, the parallel combination of said terminator pull-up resistance with said terminator pull-down resistance matching the characteristic impedance of said transmission lines such that an output resistance of said at least one on-chip terminator is approximately within ten percent of the characteristic impedance of the transmission lines.

An information handling system, comprising:

• at least three transmission lines each having a characteristic impedance, each of said transmission lines having a first end, each of said first ends being commonly connected to each other first end, and a second end;
• a plurality of drivers, each driver individually coupled to a second end of one of said transmission lines, each driver comprising a pull-down circuit having a pull-down resistance and a pull-up circuit having a pull-up resistance, the parallel combination of said pull-up resistance with said pull-down resistance matching the characteristic impedance of said transmission lines;
• at least one receiver circuit coupled to a second end of one of said transmission lines;
• and
• at least one on-chip terminator, each of said on-chip terminators having an output resistance matching the characteristic impedance of said transmission lines such that an output resistance of said at least one on-chip terminator is approximately within ten percent of the characteristic impedance of the transmission lines.

An information handling system, comprising:

• a plurality of resistance elements;
• at least a first and second transmission Line each having a characteristic impedance, each of said transmission lines having a first end and a second end wherein said first ends are coupled together through different ones of said resistance elements;
• a driver circuit connected to said second end of said first said transmission line;
• at least one receiver circuit connected to said second end of said second transmission line not connected to said driver circuit;
• and
• a plurality of on-chip terminator each terminating a second end of a different one of each said transmission lines not connected to said driver circuit, each of said terminators comprising a pull-down circuit having a pull-down resistance and a pull-up circuit having a pull-up resistance, the parallel combination of said pull-up resistance with said pull-down resistance matching the characteristic impedance of said transmission lines such that an output resistance of said at least one on-chip terminator is approximately within ten percent of the characteristic impedance of the transmission lines.

An information handling system, comprising:

• a plurality of resistance elements;
• at least two transmission lines having a characteristic impedance, each of said transmission lines having a first end and a second end wherein said first ends are coupled together through different ones of said resistance elements;
• a plurality of drivers equaling the number of transmission lines in said plurality of transmission lines, each driver coupled to a second end of a different one of said transmission lines, each driver comprising a pull-down circuit having a pull-down resistance and a pull-up circuit having a pull-up resistance, the parallel combination of said pull-up resistance with said pull-down resistance matching the characteristic impedance of said transmission lines such that an output resistance of each of said drivers is approximately equal to the characteristic impedance of the transmission lines;
• and
• at least one receiver circuit connected to a second end of one of said second transmission lines.

An information handling system, comprising:

• a plurality of resistance elements;
• at least three transmission line having a characteristic impedance, each of said transmission lines having a first end and a second end wherein said first ends are coupled together through different ones of said resistance elements;
• a plurality of drivers, each driver coupled to a second end of one of said transmission lines, each driver comprising a pull-down circuit having a pull-down resistance and a pull-up circuit having a pull-up resistance, the parallel combination of said pull-up resistance with said pull-down resistance matching the characteristic impedance of said transmission lines such that an output resistance of each of said drivers is approximately equal to the characteristic impedance of the transmission lines;
• and
• at least one receiver circuit connected to a second end of one of said transmission lines.

An information handling system, comprising:

• a plurality of resistance elements;
• at least three transmission line having a characteristic impedance, each of said transmission lines having a first end and a second end wherein said first ends are coupled together through different ones of said resistance elements;
• a plurality of drivers, each driver individually coupled to a second end of one of said transmission lines, each driver comprising a pull-down circuit having a pull-down resistance and a pull-up circuit having a pull-up resistance, the parallel combination of said pull-up resistance with said pull-down resistance matching the characteristic impedance of said transmission lines;
• at least one receiver circuit connected to a second end of one of said transmission lines;
• and
• at lease one on-chip terminator, each of said on-chip terminators having an output resistance matching the characteristic impedance of said transmission lines such that said output resistance is approximately within ten percent of said characteristic impedance of said transmission lines.

A method for operating an information handling system, comprising:

• providing at least two transmission lines each having a characteristic impedance, each of said transmission lines having a first end, each of said first ends being commonly connected to each other first end, and a second end;
• providing a plurality of drivers equaling the number of transmission lines in said plurality of transmission lines, each driver coupled to a second end of a different one of said transmission lines, each driver comprising a pull-down circuit having a pull-down resistance and a pull-up circuit having a pull-up resistance, the parallel combination of said pull-up resistance with said pull-down resistance matching the characteristic impedance of said transmission lines;
• at least one receiver circuit coupled to a second end of one of said transmission lines;
• designating one of said drivers as the active driver;
• designating each driver in said plurality of drivers other than said active driver as a terminating driver;
• causing each terminating driver to enable its pull-up circuit and pull-down circuit, to terminate the transmission line to which said terminating driver is connected such that an output resistance of each of said terminating drivers is approximately equal to said characteristic impedance of said transmission line to which said corresponding terminating drivers is connected;
• and
• causing said active driver to drive a signal onto the transmission line to which said active driver is connected.

A method for operating an information handling system, comprising:

• providing at least three transmission lines each having a characteristic impedance, each of said transmission lines having a first end, each of said first ends being commonly connected to each other first end, and a second end;
• providing a plurality of drivers equaling the number of transmission lines in said plurality of transmission lines, each driver individually coupled to a second end of one of said transmission lines, each driver comprising a pull-down circuit having a pull-down resistance and a pull-up circuit having a pull-up resistance, the parallel combination of said pull-up resistance with said pull-down resistance matching the characteristic impedance of said transmission lines;
• providing at least one receiver circuit coupled to the second end of one of said transmission lines;
• providing at least one on-chip terminator, each of said on-chip terminators comprising a pull-down circuit having a pull-down resistance and a pull-up circuit having a pull-up resistance, the parallel combination of said terminator pull-up resistance with said terminator pull-down resistance matching the characteristic impedance of said transmission lines;
• designating one of said drivers as the active driver;
• designating each driver in said plurality of drivers other than said active driver as a terminating driver;
• causing each terminating driver to enable its pull-up circuit and pull-down circuit to terminate the transmission line to which said terminating driver is connected;
• causing at least one on-chip terminator to enable its pull-up circuit and pull-down circuit to terminate the transmission line to which said at least one on-chip terminator is connected such that an output resistance of said on-chip terminator is approximately within ten percent of said characteristic impedance of the transmission line to which said terminator is connected;
• and
• causing said active driver to drive a signal onto the transmission line to which said active driver is connected.

A method for operating an information handling system, comprising:

• providing at least three transmission lines each having a characteristic impedance, each of said transmission lines having a first end, each of said first ends being commonly connected to each other first end, and a second end;
• providing a plurality of drivers, each driver individually coupled to a second end of one of said transmission lines, each driver comprising a pull-down circuit having a pull-down resistance and a pull-up circuit having a pull-up resistance, the parallel combination of said pull-up resistance with said pull-down resistance matching the characteristic impedance of said transmission lines;
• providing at least one receiver circuit coupled to a second end of one of said transmission lines;
• providing at least one on-chip terminator having an output resistance matching the characteristic impedance of said transmission lines;
• designating one of said drivers as the active driver;
• designating each driver in said plurality of drivers other than said active driver as a terminating driver;
• causing at least one terminating driver to enable its pull-up circuit and pull-down circuit to terminate the transmission line to which said terminating driver is connected;
• causing at least one on-chip terminator having an output resistance matching the characteristic impedance of said transmission lines to terminate the transmission line to which said at least one on-chip terminator is connected such that said output resistance is approximately within ten percent of said characteristic impedance of the transmission line to which said terminator is connected;
• and
• causing said active driver to drive a signal onto the transmission line to which said active driver is connected.

A method for operating an information handling system, comprising:

• providing a plurality of resistance elements;
• providing at least three transmission lines having a characteristic impedance, each of said transmission lines having a first end and a second end wherein said first ends are coupled together through different ones of said resistance elements;
• providing a plurality of drivers equaling the number of transmission lines in said plurality of transmission lines, each driver coupled to a second end of a different one of said transmission lines, each driver comprising a pull-down circuit having a pull-down resistance and a pull-up circuit having a pull-up resistance, the parallel combination of said pull-up resistance with said pull-down resistance matching the characteristic impedance of said transmission lines;
• providing at least one receiver circuit coupled to a second end of one of said transmission lines;
• designating one of said drivers as the active driver;
• designating each driver in said plurality of drivers other than said active driver as a terminating driver;
• causing each terminating driver to enable its pull-up circuit and pull-down circuit, to terminate the transmission line to which said terminating driver is connected such that an output resistance of each of said terminating drivers is approximately equal to said characteristic impedance of said transmission line to which said corresponding terminating drivers is connected;
• and
• causing said active driver to drive a signal onto the transmission line to which said active driver is connected.

A method for operating an information handling system, comprising:

• providing a plurality of resistance elements;
• providing at least two transmission lines having a characteristic impedance, each of said transmission lines having a first end and a second end wherein said first ends are coupled together through different ones of said resistance elements;
• providing a plurality of drivers, each driver individually coupled to a second end of one of said transmission lines, each driver comprising a pull-down circuit having a pull-down resistance and a pull-up circuit having a pull-up resistance, the parallel combination of said pull-up resistance with said pull-down resistance matching the characteristic impedance of said transmission lines;
• providing at least one receiver circuit coupled to a second end of one of said transmission lines;
• providing at least one on-chip terminator, each of said on-chip terminators comprising a pull-down circuit having a pull-down resistance and a pull-up circuit having a pull-up resistance, the parallel combination of said terminator pull-up resistance with said terminator pull-down resistance matching the characteristic impedance of said transmission lines;
• designating one of said drivers as the active driver;
• designating each driver in said plurality of drivers other than said active driver as a terminating driver;
• causing at least one terminating driver to enable its pull-up circuit and pull-down circuit to terminate the transmission line to which said terminating driver is connected such that an output resistance of said terminating driver is approximately equal to said characteristic impedance of said transmission line to which said terminating driver is connected;
• and
• causing at least one on-chip terminator to enable its pull-up circuit and pull-down circuit to terminate the transmission line to which said at least one on-chip terminator is connected such that an output resistance of said on-chip terminator is approximately within ten percent of said characteristic impedance of the transmission line to which said terminator is connected;
• and
• causing said active driver to drive a signal onto the transmission line to which said active driver is connected.

A method for operating an information handling system, comprising:

• providing a plurality of resistance elements;
• providing at least three transmission lines having a characteristic impedance, each of said transmission lines having a first end and a second end wherein said first ends are coupled together through different ones of said resistance elements;
• providing a plurality of drivers, each driver individually coupled to a second end of one of said transmission lines, each driver comprising a pull-down circuit having a pull-down resistance and a pull-up circuit having a pull-up resistance, the parallel combination of said pull-up resistance with said pull-down resistance matching the characteristic impedance of said transmission lines;
• providing at least one receiver circuit coupled to a second end of one of said transmission lines;
• providing at least one on-chip terminator, each of said on-chip terminators having an output resistance matching the characteristic impedance of said transmission lines;
• designating one of said drivers as the active driver;
• designating each driver in said plurality of drivers other than said active driver as a terminating driver;
• causing at least one terminating driver to enable its pull-up circuit and pull-down circuit to terminate the transmission line to which said terminating driver is connected such that an output resistance of said at least one terminating driver is approximately equal to said characteristic impedance of said transmission line to which said at least one terminating driver is connected;
• causing at least one on-chip terminator having an output resistance matching the characteristic impedance of said transmission lines to terminate the transmission line to which said at least one on-chip terminator is connected such that said output resistance is approximately within ten percent of said characteristic impedance of the transmission line to which said terminator is connected;
• and
• causing said active driver to drive a signal onto the transmission line to which said active driver is connected.

An information handling system, comprising:

• a plurality of resistance elements;
• at least a first and second transmission line each having a characteristic impedance, each of said transmission lines having a first end and a second end wherein said first ends are coupled together through different ones of said resistance elements;
• a driver circuit connected to said second end of said first said transmission line;
• at least one receiver circuit connected to said second end of said second transmission line not connected to said driver circuit;
• and
• a plurality of on-chip terminator each terminating a second end of a different one of each said transmission lines not connected to said driver circuit, each of said terminators comprising a pull-down circuit having a pull-down resistance and a pull-up circuit having a pull-up resistance, the parallel combination of said pull-up resistance with said pull-down resistance matching the characteristic impedance of said transmission lines;
• wherein each of said resistance elements has a resistance value which is within ten percent of the result of multiplying the characteristic impedance of the transmission line by (n−2)/n where n is the number of transmission lines in the system.

An information handling system comprising:

• a plurality of resistance elements;
• at least two transmission lines having a characteristic impedance, each of said transmission lines having a first end and a second end wherein said first ends are coupled together through different ones of said resistance elements;
• a plurality of drivers equaling the number of transmission lines in said plurality of transmission lines, each driver coupled to a second end of a different one of said transmission lines, each driver comprising a pull-down circuit having a pull-down resistance and a pull-up circuit having a pull-up resistance, the parallel combination of said pull-up resistance with said pull-down resistance matching the characteristic impedance of said transmission lines;
• and at least one receiver circuit connected to a second end of one of said second transmission lines;
• wherein each of said resistance elements has a resistance value which is within ten percent of the result of multiplying the characteristic impedance of the transmission line by (n−2)/n where n is the number of transmission lines in the system.

An information handling system, comprising:

• a plurality of resistance elements;
• at least three transmission line having a characteristic impedance, each of said transmission lines having a first end and a second end wherein said first ends are coupled together through different ones of said resistance elements;
• a plurality of drivers, each driver coupled to a second end of one of said transmission lines, each driver comprising a pull-down circuit having a pull-down resistance and a pull-up circuit having a pull-up resistance, the parallel combination of said pull-up resistance with said pull-down resistance matching the characteristic impedance of said transmission lines;
• and
• at least one receiver circuit connected to a second end of one of said transmission lines;
• wherein each of said resistance elements has a resistance value which is within ten percent of the result of multiplying the characteristic impedance of the transmission line by (n−2)/n where n is the number of the transmission lines in the system.

An information handling system, comprising:

• a plurality of resistance elements;
• at least three transmission line having a characteristic impedance, each of said transmission lines having a first end and a second end wherein said first ends are coupled together through different ones of said resistance elements;
• a plurality of drivers, each driver individually coupled to a second end of one of said transmission lines, each driver comprising a pull-down circuit having a pull-down resistance and a pull-up circuit having a pull-up resistance, the parallel combination of said pull-up resistance with said pull-down resistance matching the characteristic impedance of said transmission lines;
• at least one receiver circuit connected to a second end of one of said transmission lines;
• and
• at lease one on-chip terminator, each of said on-chip terminators having an output resistance matching the characteristic impedance of said transmission lines;
• wherein each of said resistance elements has a resistance value which is within ten percent of the result of multiplying the characteristic impedance of the transmission line by (n−2)/n where n is the number of the transmission lines in the system.

A method for operating an information handling system, comprising:

• providing a plurality of resistance elements;
• providing at least three transmission lines having a characteristic impedance, each of said transmission lines having a first end and a second end wherein said first ends are coupled together through different ones of said resistance elements;
• providing a plurality of drivers equaling the number of transmission lines in said plurality of transmission lines, each driver coupled to a second end of a different one of said transmission lines, each driver comprising a pull-down circuit having a pull-down resistance and a pull-up circuit having a pull-up resistance, the parallel combination of said pull-up resistance with said pull-down resistance matching the characteristic impedance of said transmission lines;
• providing at least one receiver circuit coupled to a second end of one of said transmission lines;
• designating one of said drivers as the active driver;
• designating each driver in said plurality of drivers other than said active driver as a terminating driver;
• causing each terminating driver to enable its pull-up circuit and pull-down circuit, to terminate the transmission line to which said terminating driver is connected;
• and
• causing said active driver to drive a signal onto the transmission line to which said active driver is connected;
• wherein said step of providing said plurality of resistance elements further comprises providing a plurality of resistance elements each having a resistance value which is within ten percent of the result of multiplying the characteristic impedance of the transmission line by (n−2)/n where n is the number of the transmission lines in the system.

A method for operating an information handling system, comprising:

• providing a plurality of resistance elements;
• providing at least two transmission lines having a characteristic impedance, each of said transmission lines having a first end and a second end wherein said first ends are coupled together through different ones of said resistance elements;
• providing a plurality of drivers, each driver individually coupled to a second end of one of said transmission lines, each driver comprising a pull-down circuit having a pull-down resistance and a pull-up circuit having a pull-up resistance, the parallel combination of said pull-up resistance with said pull-down resistance matching the characteristic impedance of said transmission lines;
• providing at least one receiver circuit coupled to a second end of one of said transmission lines;
• providing at least one on-chip terminator, each of said on-chip terminators comprising a pull-down circuit having a pull-down resistance and a pull-up circuit having a pull-up resistance, the parallel combination of said terminator pull-up resistance with said terminator pull-down resistance matching the characteristic impedance of said transmission lines;
• designating one of said drivers as the active driver;
• designating each driver in said plurality of drivers other than said active driver as a terminating driver;
• causing at least one terminating driver to enable its pull-up circuit and pull-down circuit to terminate the transmission line to which said terminating driver is connected;
• causing at least one on-chip terminator to enable its pull-up circuit and pull-down circuit to terminate the transmission line to which said at least one on-chip terminator is connected;
• and
• causing said active driver to drive a signal onto the transmission line to which said active driver is connected;
• wherein said step of providing said plurality of resistance elements further comprises providing a plurality of resistance elements each having a resistance value which is within ten percent of the result of multiplying the characteristic impedance of the transmission line by (n−2)/n where n is the number of the transmission lines in the system.

A method for operating an information handling system, comprising:

• providing a plurality of resistance elements;
• providing at least three transmission lines having a characteristic impedance, each of said transmission lines having a first end and a second end wherein said first ends are coupled together through different ones of said resistance elements;
• providing a plurality of drivers, each driver individually coupled to a second end of one of said transmission lines, each driver comprising a pull-down circuit having a pull-down resistance and a pull-up circuit having a pull-up resistance, the parallel combination of said pull-up resistance with said pull-down resistance matching the characteristic impedance of said transmission lines;
• providing at least one receiver circuit coupled to a second end of one of said transmission lines;
• providing at least one on-chip terminator, each of said on-chip terminators having an output resistance matching the characteristic impedance of said transmission lines;
• designating one of said drivers as the active driver;
• designating each driver in said plurality of drivers other than said active driver as a terminating driver;
• causing at least one terminating driver to enable its pull-up circuit and pull-down circuit to terminate the transmission line to which said terminating driver is connected;
• causing at least one on-chip terminator having an output resistance matching the characteristic impedance of said transmission lines to terminate the transmission line to which said at least one on-chip terminator is connected;
• and
• causing said active driver to drive a signal onto the transmission line to which said active driver is connected;
• wherein said step of providing said plurality of resistance elements further comprises providing a plurality of resistance elements each having a resistance value which is within ten percent of the result of multiplying the characteristic impedance of the transmission line by (n−2)/n where n is the number of the transmission lines in the system.