LT2940 - Power and Current Monitor - Linear Technology - #1

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LT2940 1 2940f TYPICAL APPLICATION DESCRIPTION Power and Current Monitor The LT®2940 measures a high side current and a differential voltage, multiplies them and outputs a 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 fl ow. An integrated comparator with inverting and noninverting 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, fi ltering and time integration as simple as selecting external resistors and/or capacitors. Load Monitor Alarms Above 60W FEATURES APPLICATIONS n Four-Quadrant Power Measurement n ±5% Power Measurement Accuracy n 4V to 80V High Side Sense, 100V Max n Current Mode Power and Current Outputs n Output Bandwidth Exceeds 500kHz n ±3% Current Measurement Accuracy n 6V to 80V Supply Range, 100V Max n Inverting and Noninverting Open-Collector Comparator Outputs n Available in 12-Pin DFN (3mm × 3mm) and 12-Lead MSOP Packages n Board Level Power and Current Monitoring n Line Card and Server Power Monitoring n Power Sense Circuit Breaker n Power Control Loops n Power/Energy Meters n Battery Charger Metering CMP+ PMON IMON CMPOUT CMPOUT LATCH V– V+ I+ I– 2940 TA01a VCC 110k + – 10.0k 0A TO 10A LED ON WHEN PLOAD > 60W PLOAD = VLOAD • ILOAD VLOAD 6V TO 80V ILOAD LT2940 GND 20mÙ 2W 5V 1k VIMON = ILOAD • 100 mV A VPMON = PLOAD • 20.75 mV W 24.9K 4.99k LOAD kV = kI = 20mÙ 1 12 ILOAD (A) PLOAD (W) 0 VPMON (V) 2.0 1.5 1.0 2 4 6 8 10 12 14 0.5 0 2.5 96 72 48 24 0 120 80V 30V 15V 10V 2940 TA01b LED ON LED OFF VLOAD= 6V 60W ALARM Monitor Output Level and Load Power L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners.