INA229-Q1: Low side connection & VBUS HV Sensing

Predrag Pejic2

Part Number: INA229-Q1

I would like to use INA229-Q1 on the 454V system using low-side current measurement. Although I know INA229Q1 is capable of low side sensing, my question is related to VBUS.

Is it possible to measure 454V bus voltage using a resistor divider to scale the 0-454V to tolerable 0-50V?

Thank you.

over 3 years ago

0 kai klaas69 over 3 years ago

Guru 140200 points

Hi Predrag,

if it is possible, which I believe, then you should take into account that the total resistance of internal voltage divider (1M typical) could show drastical manufacturing tolerances and temperature drift. So, in order to reduce the additional error due to internal resistance, you would need to keep the external voltage divider sufficiently low ohmic.

Kai

0 Predrag Pejic2 over 3 years ago in reply to kai klaas69

Prodigy 40 points

Hi Kai,

I guess then that buffering the signal with the opamp after the divider would do the trick just fine.

Cheers,

0 kai klaas69 over 3 years ago in reply to Predrag Pejic2

Guru 140200 points

Yes, good idea :-)

Kai

0 Mitch M over 3 years ago in reply to kai klaas69

TI__Mastermind 19375 points

Hello Predrag,

Yes, Kai is correct here in that using a voltage divider (and suggested buffer), will work fine. One important note is that you will then have to scale any results values that depend on VBUS accordingly to get accurate results.

0 Predrag Pejic2 over 3 years ago in reply to Mitch M

Prodigy 40 points

Of course. That is however fairly easy to do in post-processing. Thanks for the quick support!

0 Mitch M over 3 years ago in reply to Predrag Pejic2

TI__Mastermind 19375 points

You're welcome! Let us know if you have any more questions.

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INA229-Q1: Low side connection & VBUS HV Sensing