Impedance updating apparatus of termination circuit and impedance updating method thereof

An impedance updating, termination circuit, comprising:

• separate update controllers having a first inverter and a second inverter receiving an external input signal, a first latch connected to an output of the first inverter to store impedance information from a programmable impedance up controller, and a second latch connected to an output of the second inverter to store impedance information from a programmable impedance down controller,
• wherein the separate controller output an impedance update control signal of an up-terminator when the external input signal is a logic “high”, and output an impedance update control signal of an down-terminator when the external input signal is a logic “low”;
• and
• a terminator circuit having an up-terminator and a down-terminator connected to a common external input signal,
• wherein the terminator circuit receives impedance information from the first latch to update impedance of the up-terminator when a control signal for controlling an impedance update of the up-terminator is input from the separate update controller, and receives impedance information from the second latch to update impedance of the down-terminator when a control signal for controlling an impedance update of the down-terminator is input from the separate update controller.

An impedance updating termination circuit, comprising:

• a receiver circuit to receive an external input signal;
• a separate update controller having:
• an inverter connected to a second latch at its output;
• an input buffer connected to an output of the receiver circuit at its input and to an internal clock signal determining set-up time or hold time, and the output of the buffer connected to a first latch at its output and connected to the inverter at its output;
• the first latch for storing impedance information from a programmable impedance up controller;
• and the second latch for storing impedance information from a programmable impedance down controller, wherein the separate controller generates an up-update or down-update control signal in response to an up level or down level of an external input signal that passed through the receiver circuit to thereby control separately an up-update or down-update of impedance;
• and
• a terminator circuit having an up-terminator and a down-terminator connected to a common external input signal from the transmitter circuit, wherein the terminator circuit receives impedance information from the first latch to update impedance of the up-terminator when a control signal for controlling an impedance update of the up-terminator is input from the separate update controller, and receives impedance information from the second latch to update impedance of the down-terminator when a control signal for controlling an impedance update of the down-terminator is input from the separate update controller.

An impedance updating method of a termination circuit having up/down terminators and separate update controllers for detecting terminator through which minimum current flows in response to level of an external input signal, comprising the steps of:

• determining signal levels of the external input signal to thereby detect a terminator through which minimum current flows between the up- or down-terminator;
• separately storing first stored impedance information and second stored impedance information;
• and
• impedance updating the detected terminator through which minimum current flows in accordance with the separately stored first and second impedance information.