Liquid level sensing device and method

Abstract

A liquid level sensor device () includes a liquid level sensor element (), a capacitance-to-voltage converter (), and a controller (). The liquid level sensor element () comprises (i) at least two sets of N conductive electrodes () and (ii) M sense lines (S-S), where M is greater than or equal to N within each set of the at least two sets of conductive electrodes. Each of the M sense lines couples to select ones of the N conductive electrodes of the at least two sets of conductive electrodes to form a number of L sets of parallel coupled conductive electrodes, where L equals M. The capacitance-to-voltage converter () periodically measures a capacitance of the L sets of parallel coupled conductive electrodes for each of the M sense lines. The controller () establishes initial measured baseline capacitance values for each of the L sets of parallel coupled conductive electrodes and an initial liquid level height value. The controller () also detects transitions in the measured capacitance of the L sets of parallel coupled conductive electrodes. Responsive to the detected transitions corresponding to incremental changes in measured capacitance values, the controller updates the liquid level height value.