Amplifier system with current-mode servo feedback

An amplifier apparatus comprising:

• differential inputs disposed to receive a first and second input signal;
• a primary differential amplifier having inverting and non-inverting input nodes receiving said first and second input signal through respective first and second impedance elements and providing a main output signal;
• and
• feedback circuitry disposed to sample said main output signal and convey complementary current-mode negative feedback signals to said inverting and non-inverting input nodes, wherein said current-mode feedback signals are each servo feedback signals having the same low-pass characteristic.

An amplifier apparatus comprising:

• a first input differential amplifier disposed to receive a first input signal at its non-inverting input and output a first intermediate output signal;
• a second input differential amplifier disposed to receive a second input signal at its non-inverting input and output a second intermediate output signal;
• a primary differential amplifier disposed to receive at its non-inverting input said first intermediate output signal conveyed through a first impedance element and to receive at its inverting input said second intermediate output signal conveyed through a second impedance element, and provide a main output signal at its output node;
• and
• feedback circuitry disposed to sample said main output signal and convey a first negative feedback signal to said inverting input of said first input differential amplifier, and a second negative feedback signal to said inverting input of said second input differential amplifier.

A signal detection and amplification system comprising amplifier apparatus having:

• differential inputs disposed to receive a first and second input signal;
• a primary differential amplifier receiving said first and second input signal and providing a main output signal;
• and
• feedback circuitry disposed to sample said main output signal and convey complementary current-mode negative feedback signals to said differential inputs.