DRV8245-Q1: Control ITRIP using DAC

Zeming Kong

Part Number: DRV8245-Q1

Hi team,

My customer is using DAC to control the ITRIP.

Max current is 6A, RIPRORI is using 3kohm, VIPROPI is 2.77V typ.

Considering ITRIP = ((VITRIP - VDAC) / RIPROPI) X AIPROPI, the ITRIP accuracy will be influenced by AIPRORI error and VITRIP error.

In worst case, actual ITRIP could be > +/- 1A comparing to expected ITRIP.

Do you have any method to improve the ITRIP accuracy?

Best,
Zeming

0 Shinya Morita over 2 years ago

Hi,

Thank you for your questions. I will review it and feedback to you by next Tuesday.

regards

Shinya Morita

0 Shinya Morita over 2 years ago in reply to Shinya Morita

Hi Zeming san

Thank you for your questions. Yes AIPROPI error and VITRIP error will be impact to total accuracy. AIPROPI is +/-5% range since current level is >2A.

No way to further improvement.

regards

Shinya Morita

0 Zeming Kong over 2 years ago in reply to Shinya Morita

Morita-san,

Thanks for your confirmation.

If AIPROPI error and VITRIP error will be impact to total accuracy, even we simply use this device without DAC control, the error still remains.

For example, if we set RIPRORI 3kohm, VIPROPI 2.97V typ, VIRPOPI range will be 2.67V~3.17V, AIPROPI 6400 will be 6080~6720.

Then expected ITRIP is 6.34A, min ITRIP is 5.4A, max ITRIP is 7.1A, error is about 15%, which does not show a very good accuracy.

I guess actually min VIPRORI and min AIPROPI may not happen at the same time, ITRIP accuracy should be better.

Do you have any data for the total ITRIP regulation accuracy?

Best,
Zeming

+1 Shinya Morita over 2 years ago in reply to Zeming Kong

Hi Zeming san

Thank you for your questions.

We do not have combined characterization data. So on calculation, we need to sum up them.

regards

Shinya Morita

0 Zeming Kong over 2 years ago in reply to Shinya Morita

Understood. Thanks for your support!

Best,
Zeming

Motor drivers forum