Patent ID: 7453270
Filing Date: 2008-11-18
Classification: G01R

Abstract:
1. A system for determining a capacitance value of a measurable capacitance, the system comprising: an integrating capacitance configured to store charge received from the measurable capacitance; a charge changing circuit coupled to the integrating capacitance, the charge changing circuit including at least one delta capacitance; and a controller configured to determine the capacitance value by repeatedly applying a predetermined voltage to the measurable capacitance, repeatedly sharing charge between the measurable capacitance and the integrating capacitance to accumulate charge on the integrating capacitance, repeatedly measuring a voltage on the integrating capacitance using a quantizer of the controller and generating quantized values responsive to the repeated measurings, repeatedly changing charge on the integrating capacitance by a quantized amount of charge based on the quantized values using the delta capacitance in the charge changing circuit, and determining the capacitance value of the measurable capacitance by digitally filtering the quantized values.