Reference voltage driving circuit and pipelined analog to digital converter including same

A pipelined ADC comprising:

• a first source follower for receiving a predetermined first reference voltage (REFT) to output a first output voltage (RTOP_MDAC) corresponding to the first reference voltage;
• a second source follower for receiving a second reference voltage different from the first reference voltage to output a second output voltage (RBOT_MDAC) corresponding to the second reference voltage;
• an amplifier part for receiving the first output voltage and the second output voltage to output output signals (RTOP_FL) (RBOT_FL) amplified in unity gains;
• a first converting part for converting to a first digital signal a first analog signal sampled and held by receiving a predetermined analog signal;
• a second converting part (2≦i≦n) for receiving the signal held by the first converting part and a first digital signal, and outputting i th digital signal for every i th circuit block including a plurality (n) of circuit blocks;
• and
• a DCL for processing the first to the n th digital signals outputted from the first converting part and the second converting part and outputting a final digital signal,
• wherein the i circuit block of the second converting part comprises:
• an MDAC for converting the i−1 digital signal outputted from an i−1 stage to a reference voltage, based on the first and second output voltages as reference voltages, and for outputting the i th analog signal summed with the i−1 analog signal outputted from the i−1 stage;
• and
• a flash ADC for converting the i analog signal to the i th digital signal and outputting it, based on the output signals (RTOP_FL) and (RBOT_FL) amplified by the amplifier.