ADM1191-2ARMZ-R7(RevB) View Datasheet(PDF) - Analog Devices
Part Name
Description
Manufacturer
ADM1191-2ARMZ-R7 Datasheet PDF : 16 Pages
| |||
APPLICATIONS INFORMATION
ALERTB OUTPUT
The ALERTB output is an open-drain pin with 30 V tolerance.
This output can be used as an overcurrent flag by connecting it
to the general-purpose logic input of a controller. During normal
operation, this output is pulled high (an external pull-up resistor
should be used because this is an open-drain pin). When an
overcurrent condition occurs, the ADM1191 pulls this output low.
3.15V TO 26V
RSENSE
VCC SENSE
ALERTB
ADM1191
SETV
SDA
SCL
CONV
A1
GND A0
CONTROLLER
INTERRUPT
P = VI
SDA
SCL
CONV
Figure 25. Using the ALERTB Output as an Interrupt
SETV PIN
The SETV pin allows the user to adjust the current level that
trips the ALERTB output. The output of the current sense amplifier
is compared with the voltage driven onto the SETV pin. If the
current sense amplifier output is higher than the SETV voltage,
the output of the comparator asserts. By driving a different
voltage onto the SETV pin, the ADM1191 detects an overcurrent
condition at a different current level, with a gain of 18. See
Figure 12 for an illustration of this relationship.
ADM1191
RSENSE
ILOAD
VCC
SENSE
A CURRENT
SENSE
AMPLIFIER
ADM1191
APPLIED
VOLTAGE
SETV
COMPARATOR
ALERT
ALERTB
Figure 26. SETV Operation
KELVIN SENSE RESISTOR CONNECTION
When using a low value sense resistor for high current
measurement, the problem of parasitic series resistance can
arise. The lead resistance can be a substantial fraction of the
rated resistance, making the total resistance a function of lead
length. This problem can be avoided by using a Kelvin sense
connection. This type of connection separates the current path
through the resistor and the voltage drop across the resistor.
Figure 27 shows the correct way to connect the sense resistor
between the VCC pin and the SENSE pin of the ADM1191.
SENSE RESISTOR
CURRENT
FLOW FROM
SUPPLY
CURRENT
FLOW TO
LOAD
KELVIN SENSE TRACES
VCC
SENSE
ADM1191
Figure 27. Kelvin Sense Connections
Rev. B | Page 15 of 16
Share Link: 