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CHOPPER STABILIZED AMPLIFIER

  • US 20170111018A1
  • Filed: 10/14/2016
  • Published: 04/20/2017
  • Est. Priority Date: 10/16/2015
  • Status: Active Grant
First Claim
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1. A chopper stabilized amplifier comprising:

  • a non-inverting input pin that receives a first voltage;

    an inverting input pin that receives a second voltage;

    a main amplifier that generates an output signal according to a difference between the first voltage and the second voltage; and

    a correction circuit,wherein the main amplifier comprises;

    a differential input stage that generates a first current signal, wherein the differential input stage includes a first gm amplifier having a non-inverting input terminal connected to the non-inverting input pin and an inverting input terminal connected to the inverting input pin; and

    an output stage that receives the first current signal so as to generate the output signal of the main amplifier,wherein the correction circuit comprises;

    a second gm amplifier configured as a fully differential amplifier that amplifies a voltage difference between its non-inverting input terminal and its inverting input terminal, so as to output a differential current signal from its inverting output terminal and its non-inverting output terminal;

    an integrating circuit that integrates a differential input current input to its non-inverting input terminal and its inverting input terminal, that samples and holds the current integrated for a predetermined period, and that generates a differential voltage signal;

    a first selector arranged as an upstream stage of the second gm amplifier, so as to switch a state between;

    (i) a first state in which the non-inverting input pin and the inverting input pin are respectively connected to the inverting input terminal and the non-inverting input terminal of the second gm amplifier; and

    (ii) a second state in which the non-inverting input pin and the inverting input pin are respectively connected to the non-inverting input terminal and the inverting input terminal of the second gm amplifier;

    a second selector arranged downstream from the second gm amplifier, so as to switch a state between;

    (i) a first state in which the inverting output terminal and the non-inverting output terminal of the second gm amplifier are respectively connected to the inverting input terminal and the non-inverting input terminal of the integrating circuit; and

    (ii) a second state in which the inverting output terminal and the non-inverting output terminal of the second gm amplifier are respectively connected to the non-inverting input terminal and the inverting input terminal of the integrating circuit; and

    a third gm amplifier that converts the differential voltage signal generated by the integrating circuit into a second current signal, and that superimposes the second current signal on the first current signal.

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