A simplified functional diagram of the current sensing circuitry of the LMD18200 is shown in the following schematic.
According to the datasheet, LMD18200
has a unique feature circuitry that allow the sensing of current
through the load without affecting the supply or ground return lines.
A common method
for sensing the load current is to insert a small valued power resistor
in series with either the VCC supply or ground lines and detect the
voltage drop across this resistor.