VBAT values not following voltage

Nir Dvash

Hi All,

In my product i have a 84.5K/1% resistor connected between VBAT and my battery. When reading

the values i get from the PM_GET_DATA command, i do see the figures following the voltage change but when i increase the voltage to more then 3.879V, the reading stops following the voltage. On the PPWC, the VBAT monitoring is set to ON with a 84.5K resistor defined. The figures i get are:

"Lowest measurable voltage is in the range of 1.86 to 2.38V"

"Highest measurable voltage is in the range of 3.19 to 4.27V"

So i do not see any reason for it to stop at 3.879V.

Any ideas?

Thank you,

Nir.

over 11 years ago

0 Kristoffer S over 11 years ago

TI__Expert 7160 points

Hi Nir,

It is perhaps not very clear, but the ranges are due to chip-to-chip variations, menaing that some chips are able to measure voltages all the way up to 4.27V, but other chips are only able to measure up to 3.19V. So with the resistor you have chosen you can only guarantee that you can measure voltages between 2.38V and 3.19V.

Best regards

Kristoffer

0 Nir Dvash over 11 years ago in reply to Kristoffer S

Intellectual 660 points

Hi Kristoffer,

Hope you are doing well. Thank you for your answer. So, if i understand you correctly, if i change the resistor

to a 122K one, i will be able to safely and accurately measure battery voltages of 3.13V to 4.30V on all IC's burned

to this settings?

Nir.

0 Kristoffer S over 11 years ago in reply to Nir Dvash

TI__Expert 7160 points

Hi Nir,

Yes, correct.

-Kristoffer

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VBAT values not following voltage