Patent ID: 7319421

Claim:
A sigma-delta integrator comprising: a sensor excitation node; an integrator input node; an amplifier having a first input, a second input and an output; an auto-zero capacitor connected between the integrator input node and the first input of the amplifier; a feedback capacitor having a first terminal connected to the output of the amplifier, and having a second terminal that is connected to the first input of the amplifier during an auto-zero phase and is connected to the integrator input node during an integration phase; a first sensor capacitor connected to the sensor excitation node and selectively connected to the integrator input node; a sensor excitation signal source connected to the sensor excitation node for providing to the first sensor capacitor a sensor excitation signal having a first supply voltage level during the auto-zero phase and a second supply voltage level during the integration phase; and a circuit for providing to the integrator input node, during the auto-zero phase, a voltage that is a function of leakage resistance of the first sensor capacitor.