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confused about adm1191 application

Question asked by KenHoo on Apr 25, 2013
Latest reply on Apr 26, 2013 by Ren

hi there .

i plan to use adm1191 monitor to measure another chip's input voltage and current . and my teacher request a theoratical analysis . i got 2 questions while reading the datasheet:

1. the voltage supply of 1191 ranged from 3.15V to 26V , does that mean we can only measure voltages from 3.15V to 26V using this chip?

2.  on page 13 of the datasheet it says while converting ADC codes to voltage and current readings we can use equations as below :

Voltage = (VFULLSCALE/4096) × Code

where: VFULLSCALE = 6.65 V (7:2 range) or 26.52 V (14:1 range). Code is the ADC voltage code read from the device (Bit V11 to Bit V0).

Current = ((IFULLSCALE/4096) × Code)/Sense Resistor

where: IFULLSCALE = 105.84 mV

does that mean if i want to reach fullscale i can only using 6.65V or 26.52V as power supply? if so , what would happen if i use 3.3V as power supply?