Rail-to-rail comparator, pulse amplitude modulation receiver, and communication system using the same

A rail-to-rail comparator comprising:

• a first comparison unit configured to compare differential input signals to differential reference voltages;
• a second comparison unit configured to compare the differential input signals to the differential reference voltages;
• and
• an output unit configured to be driven in response to a clock signal, the output unit connected logically between the first and second comparison units, and configured to generate a complementary output signal.

A rail-to-rail comparator comprising:

• a first comparison unit configured to compare first and second input signals having a differential relationship to first and second reference voltages having a differential relationship, respectively;
• a second comparison unit configured to compare the first and second input signals to the first and second reference voltages, respectively;
• and
• an output unit configured to be connected logically between the first and second comparison units, and configured to generate an output signal according to an amount of current flowing through the first and second comparison units, in response to a clock signal.

A pulse amplitude modulation (PAM) receiver comprising:

• a comparison circuit configured to generate and compare differential input signals to differential reference voltages and generate an output signal;
• a decoder configured to restore a signal outputted from the comparison circuit into a data signal;
• and
• an output circuit configured to amplify and output the data is signal outputted from the decoder,
• wherein the comparison circuit comprises:
• a first comparison unit configured to compare the differential input signals to the differential reference voltages;
• a second comparison unit configured to compare the differential input signals to the differential reference voltages;
• and
• an output unit configured to be driven in response to a clock signal, and the output unit configured to generate a complementary output signal according to a comparison result of the first and second comparison units.

A PAM communication system comprising:

• a transmitter configured to generate and output signals having any one level of a level to multiple levels, as a differential signal pair;
• and
• a receiver comprising a comparison circuit configured to receive the differential signal pair, compare the received differential signal pair to differential reference voltages, and generate an output signal,
• wherein the comparison circuit comprises:
• a first comparison unit configured to compare the differential signal pair to the differential reference voltages;
• a second comparison unit configured to compare the differential signal pair to the differential reference voltages;
• and
• an output unit configured to be driven in response to a clock signal, and configured to generate a complementary output signal according to comparison results of the first and second comparison units.