Patent ID: 8278968

Claim:
A termination control circuit comprising: a first node to receive a first reference voltage; a second node to receive a second reference voltage; an adjustable resistor exhibiting an adjustable impedance responsive to an impedance-control signal; a comparator having a first input coupled to the first node to receive the first reference voltage, a second input coupled to the second node via the adjustable resistor, and a comparator output; a transistor disposed in a path between the second input and a supply terminal, the supply terminal to receive a third reference voltage; and a counter operatively coupled between the comparator output and the adjustable resistor, the counter to update the impedance-control signal responsive to a signal from the comparator output; wherein updating the impedance-control signal adjusts the impedance between the second node and the second input of the comparator; and wherein the transistor selectively disables current flow through the adjustable resistor.