Linear Launches Current Monitor For 4-80V Systems
Linear Technology has introduced the LT2940, a power and current monitor for 4 to 80V systems. The LT2940 provides the necessary circuits to accurately measure, monitor and control power in situations where both the current and voltage may vary due to supply-voltage uncertainty, component parametric changes, transient conditions or time-varying signals.
It uses a true four-quadrant analogue multiplier that results in five per cent power-measurement accuracy and three per cent 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 variety of metering applications. It 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. The LT2940 is offered in commercial and industrial versions, supporting operating temperature ranges from 0 to 70C and -40 to 85C, respectively. It is available in RoHS-compliant, 12-pin 3 x 3mm DFN and 12-lead MSOP packages.
It uses a true four-quadrant analogue multiplier that results in five per cent power-measurement accuracy and three per cent 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 variety of metering applications. It 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. The LT2940 is offered in commercial and industrial versions, supporting operating temperature ranges from 0 to 70C and -40 to 85C, respectively. It is available in RoHS-compliant, 12-pin 3 x 3mm DFN and 12-lead MSOP packages.
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