A 0.35 μm CMOS voltage derivative sensor with sign and inflection outputs

A wideband first-order voltage differentiation circuit relies on switched capacitor (SC) techniques to yield an indication of slew direction. Fabricated in a 0.35 μm CMOS process using double poly capacitors, the circuit incorporates a window comparator to facilitate detection of inflection regions. The circuit´s sensitivity is adjustable by varying the measurement time-interval along with the threshold voltages of the window comparator and offers advantages over conventional differentiator schemes relying on resistors and capacitors.