Patent ID: 8451063
Filing Date: 2013-05-28
Classification: H03F

Abstract:
1. A sensor system comprising: a sensor having a capacitance value and an output, an amplifier having an input connected to the sensor output, and a negative capacitance circuit electrically connected in parallel with said sensor output, wherein said negative capacitance circuit comprises: a first and second transistor, each having a base, an emitter and a collector, wherein the first transistor's said collector being connected to said sensor output and said emitter being connected to a first current source, and the second transistor's said collector being connected to a ground voltage level and said emitter being connected to a second current source, a capacitor electrically connected between said emitters of said transistors, a third current source being connected to the output of said sensor, a second amplifier having a non-inverting input connected to said sensor output, an inverting input connected to ground level, a non-inverting output connected to the base of said first transistor, and an inverting output connected to the base of said second transistor, wherein said first and second transistor and said capacitor act as a differential pair for an AC input signal.