Patent ID: 6127891
Filing Date: 2000-10-03
Classification: H03F

Abstract:
An apparatus including a low voltage amplifier with gain boosting and a reduced power supply voltage requirement, comprising:first and second power terminals configured to convey a power supply voltage;a gain boost control circuit, coupled between said first and second power terminals, configured to receive said power supply voltage and a plurality of input signals and in accordance therewith provide a plurality of gain boost control signals;a cascode amplifier circuit, coupled between said first and second power terminals and to said gain boost control circuit, configured to receive said power supply voltage, a portion of said plurality of input signals and said plurality of gain boost control signals and in accordance therewith provide a plurality of gain boosted signals which correspond to said plurality of input signals; anda class AB amplifier circuit, coupled between said first and second power terminals and to said cascode amplifier circuit, configured to receive said power supply voltage and said plurality of gain boosted signals and in accordance therewith provide a class AB output signal which corresponds to said plurality of input signals;wherein said cascode amplifier circuit, said gain boost control circuit and said class AB amplifier circuit together operate with a minimum power supply voltage from said first and second power terminals which equals a sum of:one active transistor input bias potential acrossgate and source terminals of a metal oxide semiconductor field effect transistor, orbase and emitter terminals of a bipolar junction transistor;one active transistor output bias potential acrossdrain and source terminals of another metal oxide semiconductor field effect transistor, orcollector and emitter terminals of another bipolar junction transistor; andanother active transistor output bias potential acrossdrain and source terminals or still another metal oxide semiconductor field effect transistor, orcollector and emitter terminals of still another bipolar junction transistor.