Current mode chopper amplifier

Abstract

A circuit, comprising an input chopper configured to receive an input signal, a differential amplifier having an input coupled to an output of the input chopper, a current mode chopping circuit coupled to an output of the differential amplifier, and a first current mirror bias transistor pair coupled between a voltage supply and the current mode chopping circuit.

What is claimed is: 
     
         1 . A circuit, comprising:
 an input chopper configured to receive an input signal;   a differential amplifier having an input coupled to an output of the input chopper;   a current mode chopping circuit coupled to an output of the differential amplifier; and   a first current mirror bias transistor pair coupled between a voltage supply and the current mode chopping circuit.   
     
     
         2 . The circuit of  claim 1 , further comprising a first bias cascode transistor pair coupled between the first current mirror bias transistor pair and a second bias cascode transistor pair coupled to the current mode chopping circuit. 
     
     
         3 . The circuit of  claim 1 , further comprising a current source coupled to gate terminals of the first current mirror bias transistor pair. 
     
     
         4 . A circuit, comprising:
 a first stage comprising an input chopper circuit, a first amplifier, and a current mode chopper circuit;   a second stage comprising a second amplifier;   a third stage comprising a third amplifier; and   a feed-forward path comprising a fourth amplifier.   
     
     
         5 . The circuit of  claim 4 , wherein an input of the first stage is coupled to an input of the feed-forward path and configured to receive a differential input signal, wherein an output of the first stage is coupled to an input of the second stage, and wherein an output of the second stage is coupled to an output of the feed-forward path and an input of the third stage.