What is the ALS and BLS pin for on the ISL83204A full-bridge driver chip?
"ALS" does not stand for "A low sense", it stands for "A low source". The two lines ALS and BLS provide the means to reference the MOSFET gate drives to the sources of the respective MOSFETs. They are not typically connected to ground. It is expected that there will be current sense resistors to ground. The outputs of these resistors, properly conditioned, are fed back to the input comparator to control the cycling of the bridge.