True Power & Current Monitor Enables Board & System-Level Optimization

Unlike traditional power monitors that rely on data converters and multiplying registers to calculate power, the LT2940 uses a true four-quadrant analog multiplier that results in 5% power measurement accuracy and 3% current measurement accuracy, ensuring that boards and systems achieve optimum power efficiency and reliability. The LT2940 is suitable for use in line cards and servers, power-sense circuit breakers, power control loops and a wide variety of metering applications.

The LT2940 measures a high-side current and differential voltage, and calculates the instantaneous power at a bandwidth exceeding 500kHz. Bidirectional high-side currents and bipolar voltage differences are correctly handled by a four-quadrant multiplier and push-pull output stage, which allow the device to indicate forward and reverse power flow. After current and voltage measurements are taken, current and power levels can be scaled, filtered and monitored separately via their respective proportional-to-current and proportional-to-power current outputs. Meanwhile, an integrated comparator with complementary open-collector outputs can be used to create PWM control loops, or provide simple logic of, for example, an over-power pin, an LED indicator alarm, a MOSFET load cutoff switch, an external fan, or a binary counter for metering applications. Together, the wide supply range, wide bandwidth and uncompromised accuracy make the LT2940 a complete versatile power monitoring solution.