Transmission circuit with equalization function and training system including the same

A transmission circuit comprising:

• a data driver comprising a plurality of driving units having different driving strengths and being coupled to an input/output pad, the data driver configured to select at least one of the plurality of driving units as a main driving unit and at least one other than the at least one as an auxiliary driving unit in response to a first impedance control signal;
• a driving strength and equalization control circuit configured to generate a plurality of main/auxiliary selection signals in response to a plurality of strength control signals, a plurality of equalization control signals, and input data;
• and
• a pre-driver configured to output a result of a logical combination of the plurality of main/auxiliary selection signals and a first impedance adjustment signal as the first impedance control signal.

A training system comprising:

• a semiconductor apparatus comprising a plurality of driving units coupled with an input/output pad,
• wherein the semiconductor apparatus is configured to perform a data transmission operation by selecting at least one main driving unit corresponding to a predetermined driving strength from among the plurality of driving units, and configured to perform an equalization operation by selecting at least one auxiliary driving unit from among remaining driving units excluding the main driving unit;
• and
• a host configured to write the semiconductor apparatus with write data having a predetermined pattern, and configured to perform a training operation by changing the auxiliary driving unit among the plurality of driving units according to read data.