Comparator for analog to digital converter

A method for converting an analog signal to a digit value, comprising:

• receiving, by a comparator, a first analog input signal and an input reference signal;
• comparing, by the comparator, the first analog signal to the input reference signal;
• outputting, by the comparator, a digital value based on the first analog signal crossing the input reference signal;
• shifting the first analog signal by an amount based on a delay between the output of the digital value and a time of the first analog signal crossing the input reference signal;
• and
• outputting the first digital value as a digital output signal representing at least a portion of the first analog input signal.

An analog-to-digital convertor (ADC) comprising:

• a cross detector configured to:
• receive an input reference signal;
• and
• output a first digital value;
• a voltage shifter circuit including:
• a comparator configured to:
• receive an analog signal and the input reference signal;
• and
• output a second digital value based on the first digital value and the analog signal;
• an up/down counter configured to receive the second digital value and output a voltage offset based on the second digital value;
• and
• a voltage level shifter configured to receive the voltage offset and output a shifted analog signal to the cross detector.