DRV8884EVM: nFault pin of DRV8884 always be low

user6413953

Part Number: DRV8884EVM

I have a problem with the DRV8884EVM。when I turn on the power （power of mcu and motor driver），mcu is good running; and then I just set nSleep pin to high, nFault pin changes to low, and keeps low until set nSleep pin to low.

Picture below is gui settings.

VM voltage is 9.6V

VCP is 7.8V

I did not connect a motor.

what problem would lead to vcp is lower than (vm +2)V, how to solve the problem？

Thanks in advance!

over 3 years ago

0 Wang5577 over 3 years ago

TI__Guru 56650 points

Hello,

Can you "Enable" the output first, and then check VCP and nFault pin voltage?

0 user6413953 over 3 years ago in reply to Wang5577

Prodigy 30 points

Wang5577 said:

Hello,

Can you "Enable" the output first, and then check VCP and nFault pin voltage?

I did as you suggested, but the fault pin is still low.

0 Alvin Zheng over 3 years ago in reply to user6413953

TI__Intellectual 900 points

Follow up on e2echina.

0 Wang5577 over 3 years ago in reply to Alvin Zheng

TI__Guru 56650 points

Alvin,

Thank you for your help. Let me check to see if we have an EVM in the lab this Friday.

0 Wang5577 over 3 years ago in reply to Wang5577

TI__Guru 56650 points

We don't have DRV8884EVM in our lab. Let me order one and check it.

0 Wang5577 over 3 years ago in reply to Wang5577

TI__Guru 56650 points

I have ordered the EVM yesterday. When it comes, I will check it.

0 Wang5577 over 3 years ago in reply to Wang5577

TI__Guru 56650 points

I have confirmed the request. But, still doesn't received the EVM sample yet.

According to the failure behave, it seems like a damaged device on the EVM. Whether customer damaged it or not will be difficult to determine. I think we should suggest ordering some samples from ti.com and try another sample. VCP is way too low. Could be some external component issue as well around charge pump.

I can reopen this post or send an email to you after I have the EVM.

0 Wang5577 over 3 years ago in reply to Wang5577

TI__Guru 56650 points

Hello,

The DRV8884EVM arrived. The nFault signal is normal. I would think the device or surrounding components may get damage. Please order an new board or replace the device, and then recheck it.

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DRV8884EVM: nFault pin of DRV8884 always be low