Bus termination voltage supply

A system which provides a first voltage on a first voltage supply node, comprising:

• a plurality of bus agents coupled to a bus to drive a signal line;
• a driver which has a driver control input and which couples said first voltage supply node to an output node, the driver providing at the output node a termination voltage for a changing load;
• a first resistive element which couples said output node to a bias voltage node;
• a second resistive element which couples said bias voltage node to a second voltage supply node;
• a bias element which couples said first voltage supply node to said driver control input;
• a bias transistor which has a control input coupled to said bias voltage node and which cooperates with the first resistive element, the second resistive element, and the bias element to compensate for voltage fluctuations in said output voltage caused by changes in the changing load at the output node couples said driver control input to said second voltage supply node;
• and
• a resistive termination coupling said termination voltage on said output node to said signal line.

A system which provides a first voltage from a first voltage supply, comprising:

• a plurality of bus agents coupled to a bus to drive a signal line;
• isolation means for isolating an output voltage from fluctuations in the first voltage while supplying current from said first voltage supply to maintain said output voltage on an output node;
• biasing means coupled to said output node and coupled to a second voltage supply, said biasing means providing a bias voltage to a control input of said isolation means;
• feedback means coupled to said biasing means and coupled to said first voltage supply, said feedback means cooperating with said biasing means to maintain said output voltage by adjusting said bias voltage provided to said control input of said isolation means to compensate for voltage fluctuations in said output voltage caused by the plurality of bus agents switching the signal line;
• and
• resistive means resistively coupling said output node to said signal line.

A system comprising:

• a plurality of bus agents coupled to drive a signal line;
• a first resistive element having a first resistive element first terminal coupled to a system voltage supply;
• a Darlington pair having a Darlington pair collector input coupled to the system voltage supply, a Darlington pair base terminal to a second terminal of the first resistive element, and a Darlington pair emitter terminal connected to supply a termination voltage to the signal line;
• a voltage divider having a first divider resistor and a second divider resistor coupled in series between the Darlington pair emitter terminal and a ground terminal, the voltage divider having a voltage divider node between the first and second divider resistors;
• and
• an NPN transistor having a transistor base terminal coupled to the voltage divider node, a transistor collector coupled to a second terminal of the first resistive element, and an emitter coupled to the ground terminal.