LMZ21701 / Reverse current

S.Satoshi

Other Parts Discussed in Thread: DRV8836, LMZ21701, LMZ21701EVM

Hi,

Our customer has evaluated LMZ21701EVM with DRV8836 to drive DCM. Now they confirmed reverse current by inductive load when DRV8836 was disabled as attached. Then can LMZ21701 accept -100mA reverse current when LMZ21701 is operated?

Best Regards,

Sonoki / Japan disty

LMZ21701 reverse current.pdf

over 10 years ago

0 Anston Lobo over 10 years ago

TI__Genius 16025 points

Hi Sonoki,

We have received your query and will get back to you very shortly.

Thanks,

Anston

0 S.Satoshi over 10 years ago in reply to Anston Lobo

Guru 21675 points

Hi Anston-san,

I really appreciate for always your prompt reply. I'm waiting for the response from your engineering team.

Best Regards,

Sonoki

0 S.Satoshi over 10 years ago in reply to S.Satoshi

Guru 21675 points

Hi Anston-san,

I'm waiting for the response from your engineering team. Thanks in advance.

Best Regards,

Sonoki

0 Akshay Mehta over 10 years ago in reply to S.Satoshi

TI__Genius 15810 points

Hello Sonoki,

By pushing current through the high side body diode, you are violating the abs max. This will cause the performance of the IC to degrade over time and a failure could happen eventually. You could use a schottky diode from Vout to Vin to channel that current away from the body diode. See attached image.

I hope this helps.

Regards,
Akshay

0 S.Satoshi over 10 years ago in reply to Akshay Mehta

Guru 21675 points

Hi Akshay-san,

In this case, the Vout is not increaced higher than Vin, so I believe that this reversed current is flowed to low side FET. Does Nano2 module have sink capabilty?

Best Regards,

Sonoki

0 Akshay Mehta over 10 years ago in reply to S.Satoshi

TI__Genius 15810 points

Sonoki,

We do not have any test data on the negative current. The datasheet does not have any negative current limit listed. If because of the inductive load transient from high load to low, the current is indeed flowing through the low side MOSFET, it might be okay. Please send us some scope shots of the switch waveform at the instant of the load transient from high to low. That should help try to understand more. But as such we do not have any data on the negative current limit.

Regards,
Akshay

0 S.Satoshi over 10 years ago in reply to Akshay Mehta

Guru 21675 points

Hi Akshay-san,

I explained about this topic to our customer by referring your comment, and could close it. Thank you for your support!!

Best Regards,

Sonoki

0 Akshay Mehta over 10 years ago in reply to S.Satoshi

TI__Genius 15810 points

You're welcome.

-Akshay

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LMZ21701 / Reverse current