ADM1192:  Digital Power Monitor with Clear Pin and ALERT Output

The ADM1192 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 and in 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. Alternatively, the ADC can run continuously, and the user can read the latest conversion data whenever it is required. Up to four unique I²C addresses can be created, depending on the way the ADR pin is 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 output exceeds the SETV voltage. This event is detected at the ALERT block. The ALERT block then charges up the external TIMER capacitor with a fixed current. When this timing cycle is complete, the ALERT output asserts.

The ALERT output can be used as a flag to warn a micro-controller or field programmable gate array (FPGA) of an overcurrent condition. ALERT outputs of multiple ADM1192 devices can be tied together and used as a combined alert.

A basic P-channel FET hot swap circuit can be implemented with the ALERT output. The value of the TIMER capacitor should be set so that the charging time of this capacitor is much longer than the period where a higher than nominal inrush current may be flowing.

The ADM1192 is packaged in a 10-lead MSOP.

Applications

Data Sheet, Rev. B, 2/08