High Side current shunt monitors are specially designed differential amplifiers for high side current sensing. They monitor the current in an application by measuring a voltage drop across a resistor placed in the current path. The output is usually a voltage that is proportional to the current through the measured path. Ohm’s law of I = V/R gives us the relationship between the measured voltage drop and the current. Current shunt monitors can measure tiny differential voltages riding on large voltages well in excess of the amplifiers power supply.