Patent ID: 7327635

Claim:
An adaptive comparator circuit, particularly for an acoustic distance sensor, comprising a first comparator ( 1 ), having a first threshold voltage input ( 1 a ) to which a first threshold voltage (U ref1 ) is applied and a first signal input ( 1 b ) to which a voltage signal (U signal ) is applied and, when a voltage signal (U signal ) is present that is greater than the first threshold voltage (U ref1 ), said comparator emits a first switching signal (S 1 ), characterized by a signal transmitter ( 2 ), especially a microcontroller or microprocessor, that at times emits a control signal (S St ), a first switch ( 3 , 103 ) that has a control means ( 3 a , 103 a ), a switch input ( 3 b , 103 b ) and a switch output ( 3 c , 103 c ), and that can be regulated or activated through the effect of the control signal (S St ) on the control means ( 3 a , 103 a ) in such a way that it is in the closed state when the signal transmitter ( 2 ) emits a control signal (S St ), and otherwise it is in the open state, or vice versa, whereby the switch input ( 3 b , 103 b ) is connected to the positive or negative first pole ( 4 a ) of a first direct voltage source and the switch output ( 3 c , 103 c ) is connected to the first threshold voltage input ( 1 a ), so that the first threshold voltage (U ref1 ) is equal to the voltage present at the switch output ( 3 c , 103 c ), a capacitor ( 6 ) via which the switch output is connected to the negative or positive pole ( 4 b ) of the first direct voltage source, and a diode ( 5 ) via which the switch output ( 3 c , 103 c ) is connected to the first signal input ( 1 b ) in such a way that the anode ( 5 a ) or the cathode ( 5 b ) of the diode ( 5 ) is connected to the switch output ( 3 c , 103 c ).