Patent ID: 8111100
Filing Date: 2012-02-07
Classification: H03F

Abstract:
1. A system for amplification of a differential input signal comprising: a first resistor coupled as a portion of a circuit branch from a first virtual short to a second virtual short, said first and second virtual shorts being driven respectively by a first and a second amplifier configured for negative feedback; a device having a first terminal coupled to said first resistor, a second terminal coupled to an output of said second amplifier, and a high impedance output terminal passing a current substantially controlled by a difference in potential between said first and said second terminals; a third amplifier having a positive input coupled to a first bias voltage through a second resistor, a negative input coupled to said first bias voltage through a third resistor, and an output node; and a fourth resistor coupled as a portion of a negative feedback path for said third amplifier; wherein said differential input signal is differentially applied to a first input of said first amplifier and a second input of said second amplifier; and said high impedance output terminal is coupled to said positive input of said third amplifier.