Digital Power Monitor
with Convert Pin and ALERTB Output
ADM1191
FUNCTIONAL BLOCK DIAGRAM
FEATURES
Powered from 3.15 V to 26 V
CONV
Precision current sense amplifier
ADM1191
Precision voltage input
SDA
V
VCC
0
12-bit ADC for current and voltage readback
Convert pin (CONV) for commanding an ADC read
SETV input for setting overcurrent alert threshold
ALERTB output provides an overcurrent interrupt
I2C® fast mode-compliant interface (400 kHz maximum)
Two address pins allow 16 devices on the same bus
10-lead MSOP
SCL
A1
2
I C
12-BIT
ADC
I
1
A
SENSE
MUX
A0
CURRENT
SENSE
AMPLIFIER
ALERT
ALERTB
SETV
COMPARATOR
APPLICATIONS
Power monitoring/power budgeting
Central office equipment
Telecommunication and data communication equipment
PCs/servers
GND
Figure 1.
3.15V TO 26V
R
SENSE
GENERAL DESCRIPTION
The ADM1191 is an integrated current sense amplifier that
offers digital current and voltage monitoring via an on-chip,
12-bit analog-to-digital converter (ADC), communicated
through an I2C interface.
VCC
SENSE
ALERTB
CONTROLLER
INTERRUPT
P = VI
ADM1191
SDA
SDA
SCL
SETV
An internal current sense amplifier senses voltage across the sense
resistor in the power path via the VCC pin and the SENSE pin.
SCL
CONV
CONV
A1
A0
A 12-bit ADC can measure the current seen in the sense
resistor, as well as the supply voltage on the VCC pin.
GND
Figure 2. Applications Diagram
An industry-standard I2C interface allows a controller to read
current and voltage data from the ADC. Measurements can be
initiated by an I2C command or via the convert (CONV) pin.
The CONV pin is especially useful for synchronizing reads on
multiple ADM1191 devices. Alternatively, the ADC can run
continuously, and the user can read the latest conversion data
whenever it is required. Up to 16 unique I2C addresses can be
created, depending on the way the A0 pin and the A1 pin are
connected.
The ALERTB output can be used as a flag to warn a micro-
controller or field programmable gate array (FPGA) of an
overcurrent condition. ALERTB outputs of multiple ADM1191
devices can be tied together and used as a combined alert.
A SETV pin is also included. A voltage applied to this pin is
internally compared to the output voltage on the current sense
amplifier. The output of the SETV comparator asserts when the
current sense amplifier ouput exceeds the SETV voltage. When
this event occurs, the ALERTB output asserts.
The ADM1191 is packaged in a 10-lead MSOP.
Rev. 0
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