Charles Kitchin and Lew Counts
Analog Devices

Difference (Subtractor) Amplifier Products Monolithic difference amplifiers are a special category of in-amps that are usually designed to be used in applications where large dc or ac common-mode voltages are present. This includes many general current sensing applications, such as motor control, battery chargers, and power converters. In addition, there are numerous high common-mode voltage automotive current sensing applications, including: battery cell voltage monitoring, transmission controls, fuel injection controls, engine management, suspension controls, electronic steering, electronic parking brake, and hybrid vehicle drive/hybrid battery control. Because these amplifiers are typically used to sense current by accurately amplifying the small differential voltage across a shunt resistor in the load path, they are often called current shunt amplifiers.