Amplifier circuit

An amplifier circuit, comprising:

• a sampling circuit configured to sample a voltage of an input signal;
• an amplifier having an input terminal connected to an output terminal of the sampling circuit;
• a feedback capacitor connected between an output terminal of the amplifier and the output terminal of the sampling circuit;
• a quantizer including a comparator that has an input terminal connected to the output terminal of the sampling circuit and configured to quantize voltage at the output terminal of the sampling circuit using a comparison result from the comparator and to output a digital code according to the comparison;
• and
• a control circuit including:
• an input terminal connected to the output terminal of the sampling circuit, and
• a register for storing a cancellation digital code for cancelling the difference between an offset of the amplifier and an offset of the comparator in response to a code storing signal;
• an offset control circuit that outputs the cancellation digital code stored in the register in response to an active calibration signal;
• and
• a signal control circuit that outputs the digital code from the quantizer in response to an inactive calibration signal;
• and
• a first digital-analog (D/A) converter configured to output an analog signal in accordance with digital codes from the control circuit.

A pipeline analog-to-digital converter, comprising:

• an encoder having an encoder output and a plurality of encoder inputs and;
• and
• a plurality of pipeline stages connected in series, each pipeline stage having a stage input and a stage output, each pipeline stage including:
• a sub-ADC having an input connected to the stage input and an output connected to one of encoder inputs in the plurality of encoder inputs;
• a sub-DAC having an input connected to the output of the sub-ADC and the one of the encoder inputs in the plurality of encoder inputs;
• a subtractor connected to the stage input and an output of the sub-DAC, the subtractor configured to provide a difference signal according to a difference between a signal received at the stage input and a signal output from the sub-DAC;
• and
• an amplifier circuit having an input terminal connected to the subtractor at which the difference signal is received, the amplifier circuit including:
• a sampling circuit configured to sample a voltage of an input signal;
• an amplifier having an input terminal connected to an output terminal of the sampling circuit;
• a feedback capacitor connected between an output terminal of the amplifier and the output terminal of the sampling circuit;
• a quantizer including a comparator that has a first input terminal connected to the output terminal of the sampling circuit and a second input terminal connected to a reference potential terminal, the quantizer configured to quantize a voltage at the output terminal of the sampling circuit according to a comparison of the voltage at the output terminal of the sampling circuit to a voltage at the reference potential terminal and to output a digital code according to the comparison;
• a control circuit receiving the digital code from the quantizer and including a register for storing the digital code as a cancellation digital code for cancelling a difference between an offset of the amplifier and an offset of the comparator;
• and
• a first digital-analog (D/A) converter configured to output an analog signal in accordance with digital codes from the control circuit.