Linear Technology's LT2940 measures high side current and differential voltage, multiplies them, and outputs current proportional to instantaneous power. Bidirectional high side currents and bipolar voltage differences are correctly handled by the four-quadrant multiplier and push-pull output stage, which allows the LT2940 to indicate forward and reverse power flow.

An integrated comparator with inverting and non-inverting open-collector outputs makes the LT2940 a complete power level monitor. In addition, an output current proportional to the sensed high side current allows current monitoring. The current mode outputs make scaling, filtering, and time integration as simple as selecting external resistors and / or capacitors.