Two terminal I.C. magnetic-field detector for use in a liquid level sensor and having an anti-slosh feature

A two-terminal integrated circuit magnetic-field detector for use in detecting the proximity of a floating magnet, comprising:

• a) a magnetic-field-to-voltage transducer;
• b) a comparator of the kind having hysteresis, for producing a one type binary output signal when the comparator input voltage exceeds one comparator threshold voltage and for producing the other type binary output signal when the transducer output voltage falls below the other predetermined threshold voltage, said comparator having an input connected to the output of said transducer;
• c) an anti-sloshing accumulator means, having an input connected to said comparator output, for producing an accumulator signal that is the integral as a function of time of the binary comparator output signal when the binary comparator output signal is of the one type, and for reducing the integrated accumulator signal at a predetermined rate during periods when the binary comparator output signal is of the other type;
• d) two integrated circuit terminal pads to which an external DC voltage source may be connected in series with an external warning lamp;
• said magnetic-field-to-voltage transducer, said comparator and said up-down accumulator means being connected to said two terminal pads for being energized by the external DC voltage source;
• and
• e) a latching driver connected between said two integrated circuit terminal pads and having an input connected to said accumulator means, said driver having a latch threshold for presenting a high impedance across said two terminal pads when the accumulator signal is in one binary state and for presenting a low impedance across said two terminal pads when the magnitude of the accumulator signal exceeds a predetermined value.