Differential amplifier with complementary unit structure

A method for signal amplification, comprising:

• comparing a common-mode voltage of an amplifier having a complementary metal-oxide-semiconductor structure with a reference voltage, the complementary metal-oxide-semiconductor structure having a first pair of transistors and a second pair of transistors;
• amplifying a differential input voltage between a first input voltage at gates of the first pair of transistors and a second input voltage at gates of the second pair of transistors;
• providing a bias current to sources of a transistor of the first pair of transistors and a transistor of the second pair of transistors based on the comparison;
• and
• generating the reference voltage such that the reference voltage is equal to a gate-to-source voltage of a replica transistor being a replica of another transistor of the second pair of transistors.

An apparatus for signal amplification, comprising:

• means for amplifying a differential input voltage between a first input voltage at gates of a first pair of transistors of a complementary metal-oxide-semiconductor structure and a second input voltage at gates of a second pair of transistors of the complementary metal-oxide-semiconductor structure;
• means for comparing a common-mode voltage of the means for amplifying with a reference voltage;
• means for providing a bias current to sources of a transistor of the first pair of transistors and a transistor of the second pair of transistors based on the comparison;
• and
• means for generating the reference voltage such that the reference voltage is equal to a gate-to-source voltage of a replica transistor being a replica of another transistor of the second pair of transistors.