HIGH-SPEED ANALOGUE-DIGITAL CONVERTER HAVING A SIGNAL ANTI-ALIASING STRUCTURE IMPROVED BY REDUCING THE NUMBER OF ELEMENTARY CELLS

摘要

The invention relates to high-resolution analogue-digital converters using differential amplifier structures that are called anti-aliasing differential amplifiers made up of differential circuits (crossed differential pairs) and loads (cascode transistors). The anti-aliasing structure according to the invention comprises, when it is desired to make four curves folded over two periods within the useful range of voltages to be converted, four anti-aliasing blocks (one per curve). The first block comprises seven differential circuits (CR0 to CR6) and eight loads (CH0 to CH7), the outermost loads (CH0 and CH7) not being connected to the output of the block. The other blocks comprise six differential circuits (CR1 to CR6) and eight loads (CH0 to CH7), the final load (CH7) of each block not being connected to the output of this block. Compared with the existing structures, a smaller footprint, a lower consumption and a higher operating speed are achieved.