Patent ID: 8004366

Claim:
An amplifier comprising: an input amplifier stage having a first input terminal and a second input terminal and having a first gain, the first input terminal receiving an input signal, the second input terminal receiving a constant DC voltage, the input amplifier stage operable from a power supply that develops a first potential between a first active supply terminal and a neutral terminal; an output amplifier stage coupled to an output of the input amplifier stage and having a second gain, the output amplifier stage operable from a power supply that develops a second potential between the first active supply terminal and a second active supply terminal and to provide an output signal; a feedback network coupled between the first input terminal and an output of the output amplifier stage; a level shifting unit coupled to the first input terminal and the feedback network, the level shifting unit responsive to a difference in magnitude between an external sense pin and the second input terminal and generate a level shifting current that enables the output amplifier stage to bring down a DC value in the output signal; and a charge pump coupled to the output amplifier stage, the charge pump operational to generate a negative supply voltage provided to the output amplifier stage and to minimize a noise associated with the negative supply voltage using a loop gain of the amplifier, wherein the loop gain is a combination of the first gain, the second gain, and a gain of the feedback network.