Patent ID: 8026759

Claim:
A multistage amplifying circuit comprising: a first amplifying circuit that, alternatively in response to a control signal: samples a first analog voltage input to the first amplifying circuit, or amplifies a difference between the first analog voltage and a first digital voltage converted from the first analog voltage, a second amplifying circuit that, alternatively in response to the control signal: samples a second analog voltage input to the second amplifying circuit, or amplifies a difference between the second analog voltage and a second digital voltage converted from the second analog voltage, wherein the first amplifying circuit and the second amplifying circuit complement each other; and a common amplifier that receives an output voltage of the first amplifying circuit and an output voltage of the second amplifying circuit, wherein the common amplifier, alternatively in response to the control signal: resets the output voltage of the first amplifying circuit and determines an output voltage by using the second amplifying circuit, or resets the output voltage of the second amplifying circuit and determines the output voltage by using the first amplifying circuit.