Analog-to-digital conversion apparatus and method having dynamic gain compensation mechanism

An analog-to-digital conversion method having dynamic gain compensation mechanism, comprising:

• receiving and performing conversion on an analog input signal to generate a digital conversion result by a first stage conversion circuit;
• calculating an analog residue between the analog input signal and the digital conversion result and feeding a pseudo-noise to the analog residue to generate a feeding result by a second stage conversion circuit, so as to perform amplification on the feeding result according to a gain parameter to generate a digital residue;
• performing correlation calculation on the pseudo-noise and the digital residue to generate a compensation gain corresponding to the gain parameter by a gain calculation circuit;
• controlling the first stage conversion circuit to operate according to a plurality of first output resolutions and recording a plurality of output code ranges of the digital residue and a plurality of gain values of the compensation gain by a control circuit;
• according to the output code ranges, setting a plurality of output code intervals that are not overlapped with each other in a full output code range that a second output resolution of the second stage conversion circuit corresponds to by the control circuit;
• calculating a plurality of interval gain values corresponding to the output code intervals according to the gain values to further establish a look-up table between the output code intervals and the interval gain values accordingly by the control circuit;
• determining one of the output code intervals that an output code amount of the digital residue locates to look up the look-up table to retrieve one of the interval gain values as a compensation gain value by a compensation gain generation circuit;
• and
• adding the digital conversion result and the pseudo-noise to obtain an added result, performing compensation on the added result according to the compensation gain value to obtain a compensated result and adding the compensated result and the digital residue to generate a digital output signal by an output calculation circuit.