CMOS folding amplifier having high resolution and low power consumption

摘要

A folding differential amplifier includes a switching preamplifier used to select between first and second differential amplifiers as a function of an input signal. The switching preamplifier includes first and second outputs that are coupled together by a first shorting switch having an open phase and a closed phase. The first and second outputs are held at a steady state value during the closed phase of the shorting switch and allowed to vary during the open phase of the shorting switch. First and second differential amplifiers each have first and second outputs and the first output of the first differential amplifier is coupled to the second output of the second differential amplifier. Similarly, the second output of the first differential amplifier is coupled to the first output of the second differential amplifier. These cross coupled outputs form first and second amplifier outputs respectively. The first and second amplifier outputs of the can be coupled together by a second shorting switch having a closed phase and an open phase. The closed phase of the second shorting switch lasting longer than the closed phase of the first shorting switch.