Chopper-Stabilized Current Feedback Amplifier

A current feedback amplifier comprising:

• a plurality of upper current mirrors coupled between a voltage supply and an upper cascode circuit, the upper current mirrors and the upper cascode circuit having a first group of chopper circuits configured to modulate current through the upper current mirrors and the upper cascode circuit;
• a plurality of lower current mirrors coupled between a lower cascode circuit and ground, the lower current mirrors and the lower cascode circuit having a second group chopper circuits configured to modulate current in the lower current mirrors and the lower cascode circuit;
• an input buffer having a non-inverting input and an inverting input and coupled between the upper and lower cascode circuits, the non-inverting and inverting inputs having a third group of chopper circuits configured to modulate current at the non-inverting and inverting inputs;
• a first and a second phase detector circuit configured to conduct current responsive to a transition current in at least one of the upper and the lower current mirrors;
• a logic circuit having inputs coupled to the first and second phase detector circuits and operable to output a logic ONE (1) if at least one of the first and second phase detectors conduct current and operable to output a logic ZERO (0) if neither the first nor second phase detector conducts current;
• a switched capacitor filter having an input coupled to an output of the upper and lower current mirrors and having an input coupled to an output of the logic circuit, the switched capacitor filter configured to turn OFF responsive to the logic ONE (1) and to turn ON responsive to the logic ZERO (0), the switched capacitor filter configured to produce a first filtered signal;
• and
• an output stage having an input coupled to receive the first filtered signal and configured to produce an output signal for the current feedback amplifier.

A current feedback amplifier comprising:

• an input buffer having a non-inverting input and an inverting input, the non-inverting and inverting inputs having a first group of chopper circuits configured to modulate current at the non-inverting and inverting inputs;
• a plurality of current mirrors coupled to the input buffer, the current mirrors having a second group of chopper circuits configured to modulate current in the current mirrors;
• phase detector circuitry coupled to the current mirrors and configured to detect a transition current in the current mirrors;
• a switched capacitor filter having an input coupled to an output of the current mirrors, wherein the switched capacitor filter is turned OFF responsive to the detection of the transition current by the phase detector circuitry, the switched capacitor filter configured to produce a first filtered signal;
• and
• an output stage having an input coupled to receive the first filtered signal and configured to produce an output signal for the current feedback amplifier.