ADM1191:  Digital Power Monitor with Convert Pin and ALERTB Output

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.

An internal current sense amplifier senses voltage across the sense resistor in the power path via the VCC pin and the SENSE pin.

A 12-bit ADC can measure the current seen in the sense resistor, as well as the supply voltage on the VCC pin.

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.

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 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.

The ADM1191 is packaged in a 10-lead MSOP.

Applications

Data Sheet, Rev. B, 2/08