LT2940_15 Datasheet, PDF (1/24 Pages) Linear Technology – Power and Current Monitor

LT2940
Power and Current Monitor
FEATURES
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
APPLICATIONS
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}
DESCRIPTION
The LT^®2940 measures a high side current and a differ-
ential 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 flow.
An integrated comparator with inverting and noninvert-
ing open-collector outputs makes the LT2940 a complete
power level monitor. In addition, an output current pro-
portional to the sensed high side current allows current
monitoring. The current mode outputs make scaling,
filtering and time integration as simple as selecting ex-
ternal resistors and/or capacitors.
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.
TYPICAL APPLICATION
Load Monitor Alarms Above 60W
6V TO 80V
5V
1k
LED ON WHEN
P_LOAD > 60W
V_PMON
=
P_LOAD
•
20.75
mV
W
k_V =
1
12
k_I = 20mΩ
I_{LOAD 0A TO 10A}
V_CC
LATCH
20mΩ
2W
I⁺
I^–
LOAD
+
V_LOAD
–
110k
CMPOUT
CMPOUT
CMP⁺
PMON
LT2940
GND
24.9K
V⁺
10.0k
V^–
IMON
V_IMON
=
I_LOAD
•
100
mV
A
4.99k
P_LOAD = V_LOAD • I_LOAD
2940 TA01a
Monitor Output Level and Load Power
2.5
80V
30V
2.0
1.5
120
15V
96
10V
V_LOAD = 6V
LED ON
72
1.0
LED OFF ₄₈
60W ALARM
0.5
24
0
0
0 2 4 6 8 10 12 14
I_LOAD (A)
2940 TA01b
2940f
1