Differential comparator for amplifying small swing signals to a full swing output

A differential comparator comprising:

• a differential amplifier comprising a pair of inputs coupled to receive a pair of small swing complementary input signals, a pair of outputs that output first complementary output signals and first and second resistors coupled in series between the pair of outputs, wherein a common node between the first and second resistors is maintained at a predetermined voltage such that an output swing of the differential amplifier is centered about the predetermined voltage;
• first and second inverters coupled to receive the first complementary output signals, wherein each inverter has a trip point voltage equal to the predetermined voltage, the first and second inverters outputting second complementary output signals in response to the first complementary output signals, wherein the second complementary output signals are full swing complementary output signals;
• cross-coupled third and fourth inverters, wherein an input of the third inverter is coupled to an output of the first inverter and an output of the third inverter is coupled to an output of the second inverter, and an input of the fourth inverter is coupled to the output of the second inverter and an output of the fourth inverter is coupled to the output of the first inverter;
• and
• fifth and sixth inverters having inputs coupled to the outputs of the first and second inverters, respectively, wherein the fifth and sixth inverters provided additional gain.

A differential comparator comprising:

• a current switch having a pair of inputs coupled to receive a pair of small swing complementary input signals and a pair of outputs that output first complementary output signals having a voltage swing centered about a predetermined voltage in response to the complementary input signals;
• and
• first and second inverters coupled to receive the first complementary output signals, wherein each inverter has a trip point voltage equal to the predetermined voltage, the first and second inverters outputting second complementary output signals in response to the first complementary output signals, wherein the second complementary output signals are full swing complementary output signals;
• cross-coupled third and fourth inverters, wherein an input of the third inverter is coupled to an output of the first inverter and an output of the third inverter is coupled to an output of the second inverter, and an input of the fourth inverter is coupled to the output of the second inverter and an output of the fourth inverter is coupled to the output of the first inverter;
• and
• fifth and sixth inverters having inputs coupled to the outputs of the first and second inverters, respectively, wherein the fifth and sixth inverters provide additional gain.

A method for generating full swing complementary signals from small swing complementary signals comprising the steps of:

• generating complementary output signals having a voltage swing centered about a predetermined voltage in response to the small swing complementary signals;
• providing the complementary output signals to a pair of inverters each having a trip voltage equal to the predetermined voltage;
• and
• outputting from the pair of inverters the full swing complementary signals.