DRV421: DRV421 output voltage

Nicola Zanforlin

Part Number: DRV421

Hello

I'm designing a current sensor using the DRV421that seems to work very well

My question is : if I have only to measure positive currents what is the best way to get a 0/5V signal (0V-->Imin=0Ampere 5-->Imax)?

Should I add and external fast operational amplifier in order to remove the 2.5V offset and get the correct amplification or can I directly work with the internal differential amplifier?

Even a range 0.5V/5V (0.5-->Imin=0Ampere 5V-->Imax) can be acceptable like other commercil sensor with ratiometric output

Thank you very much

Nicola

over 3 years ago

0 Javier Contreras4 over 3 years ago

TI__Mastermind 27690 points

Hello Nicola,

I think you can drive VrefIN to GND. I will see if this causes any error.

0 Nicola Zanforlin over 3 years ago in reply to Javier Contreras4

Prodigy 30 points

Hi Javier

Thank you for your quick reply. It'd be perfect to connect VrefIN to GND

However if it could cause troubles please suggest a suitable fast OpAmp from TI

Have a nice day

Nicola

0 Javier Contreras4 over 2 years ago in reply to Nicola Zanforlin

TI__Mastermind 27690 points

Nicola,

I will get you some error numbers in the next day or two.

0 Nicola Zanforlin over 2 years ago in reply to Javier Contreras4

Prodigy 30 points

It's ok Javier, thank you!

0 Javier Contreras4 over 2 years ago in reply to Nicola Zanforlin

TI__Mastermind 27690 points

Sorry for the delay. The biggest error will be on the low side where you are limited on the swing low of the difference amplifier. I verified and that should the biggest concern.