n-BIT CONVERTER WITH n-1 MAGNITUDE AMPLIFIERS AND n COMPARATORS

摘要

A serial-type A/D converter that uses magnitude amplifiers ("magamps") and comparators for effecting the conversion of analog signals to Gray scale code signals that are then converted to binary digital signals by a Gray scale code-to-binary portion of the serial-type A/D converter. More specifically, a serial-type A/D converter that uses an n-bit converter that has n-1 magamps and n-comparators. The n-1 magamps are cascaded such that the VOL and VOH outputs of a stage is the inputs to the next stage. The output of the comparators are input to the Gray scale code-to-binary portion of the serial A/D converter. The latching of the comparators occurs outside of the magamps. This allows for the parallel latching of the n comparators. The speed of the serial-type A/D converter is determined by the bandwidth of the magamps. The serial-type A/D converter includes an offset method that significantly reduces the effects of early voltage, VA, on the output waveforms. Each stage of the serial-type A/D converter may have any desired gain and not limited to a particular gain.