Patent ID: 8225654

Claim:
Method for liquid level detection with a liquid level detection unit ( 10 ) with a capacitive liquid level detector ( 14 ) with an input capacitance (C), said input capacitance (C) changing if the capacitive liquid level detector ( 14 ) contacts a liquid, the method comprising the following steps: generation of a clock signal (CLK) with a preset on-time (t 1 ) corresponding to a preset sensitivity of the capacitive liquid level detector ( 14 ); feeding said clock signal (CLK) both to a reference generator ( 12 ) and to the capacitive liquid level detector ( 14 ); said reference generator ( 12 ) generating a control value (CV), derived from an on/off ratio of said clock signal (CLK) and feeding said control value (CV) into a control input ( 19 ) of a comparator ( 18 ); feeding a liquid detection response signal (RS), of said capacitive liquid level detector ( 14 ) in response to said change of the input capacitance (C), into a signal input ( 20 ) of the comparator ( 18 ); said control value (CV) determining a control parameter of the comparator ( 18 ); said comparator ( 18 ) triggering an output signal at an output ( 21 ) when said liquid detection response signal (RS) of the capacitive liquid level detector ( 14 ) exceeds a threshold value (TV) in response to a change of the input capacitance (C) of the capacitive liquid level detector ( 14 ).