Patent ID: 8130034

Claim:
A rail-to-rail amplifier comprising: a first amplification unit configured to perform an amplification operation on differential input signals in a domain in which DC levels of the differential input signals are higher than a first threshold value; a second amplification unit configured to perform an amplification operation on the differential input signals in a domain in which the DC levels of the differential input signals are lower than a second threshold value which is higher than the first threshold value, the second amplification unit being cascade-coupled to the first amplification unit; and an adaptive biasing unit configured to interrupt a current path of the second amplification unit in a domain in which the DC levels of the differential input signals are higher than the second threshold value, wherein the first and second amplification units are configured to simultaneously perform the respective amplification operations in a domain in which the DC levels of the differential input signals are higher than the first threshold value but lower than the second threshold value.