DRV8305: Query regarding noise in current output of DRV8305 and DRV8962

Gautham Angadi

Part Number: DRV8305
Other Parts Discussed in Thread: DRV8962, TMS320F28379D,

Tool/software:

Hi,

We are developing a custom carrier board for motor control of two different types of motors, however, they will be operated one at a time. We are using TMS320F28379D as a controller and DRV8305 & DRV8962 as driver. We are using two sets of DRV to control two sets of motor each. Block diagram of the architecture is pasted below for your reference. Only one option is enabled during operation.

We are planning to multiplex the current sensor output of the DRV8305 and 8962, as we have limited number of ADC pins available on TMS320, we are planning to use a 3 pin header to toggle between option 1 and option 2. Is it advisable to use the same? In usual cases, trace from DRV directly goes to ADC of TMS320. Will adding a header pin between the controller and DRV introduce some noise which can lead to degradation in performance? I have attached a snippet of the header pin for your reference.

3 months ago

+1 Yara Al Shami 3 months ago

TI__Genius 15605 points

Hi Gautham,

Gautham Angadi said:
Will adding a header pin between the controller and DRV introduce some noise which can lead to degradation in performance?

Yes, you're on the right track here, a header pin could introduce additional parasitics.

Have you considered a analog multiplexer? something like one of the following?

https://www.ti.com/product/TMUX1108

https://www.ti.com/product/CD4053B

Regards,

Yara

0 Gautham Angadi 3 months ago in reply to Yara Al Shami

Prodigy 140 points

Hi,

Thank you for your suggestion, instead of the above multiplexers, can we use the below multiplexer? As we have 6 header pins, 3 for each DRVs.

www.ti.com/.../TS3A27518E-Q1

0 Yara Al Shami 3 months ago in reply to Gautham Angadi

TI__Genius 15605 points

Hi Gautham,

Yes this one could work as well.

Regards,

Yara

0 Gautham Angadi 3 months ago in reply to Yara Al Shami

Prodigy 140 points

Hi Yara,

Thank you for all the help. I understand the importance of these multiplexers. However, I have one more question.

LaunchXLF28379D and BOOSTXL-DRV8305EVM mates through header pins and that means the current sense pins of BoostXL and LaunchXL mates through the header pins and we dont see much of a difference in the performance although that has not been quantified.

It might not be possible to change our design at this point, can we still use header pins, maybe with gold contact for improved performance?

0 Yara Al Shami 3 months ago in reply to Gautham Angadi

TI__Genius 15605 points

Hi Gautham,

I'm not entirely sure, the BoostXL and LaunchXL a created to simply test the device and not intended for actual applications so something aren't optimally design on these boards.

If you've tested BoostXL and LaunchXL and compared to your own design where headers pins are not used and saw no difference in performance then I see no issue proceeding with header pins.

Regards,

Yara

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DRV8305: Query regarding noise in current output of DRV8305 and DRV8962