What does an U244B IC’s input voltage do?
The U244B is a bar graph display driver.  It lights up the LEDs in relation to the input voltage.  It is designed to work together with the U254B.  Each drives 5 LEDs.  Together they drive 10 LEDs.  The levels to turn on each LED are interleaved so that you can use the two together to get a finer grained display.

Both ICs together looks like this:



The response of the ICs to the input voltage looks like this:



You supply an input voltage between 0 and 1 volt, and the bar graph lights up in proportion to the voltage.  Higher voltage, more LEDs light up.

If the input is unconnected, it "floats" up to some higher voltage and all of the LEDs light up.

Apply 0 volts to pin 7, and all of the LEDs will shut off.

Apply 0.6 volts to pin 7, and 3 of the LEDs will light up.  

If you wire and arrange the LEDs as shown in the diagrams, you get a simple bar graph readout of the voltage.

Sort of a like a bargain basement version of the LM3914 bar graph driver.