TPS51120: Automotive EMI filtering

jars121

Part Number: TPS51120
Other Parts Discussed in Thread: TPS51220A-Q1

G'day,

I'm using the TPS51120 as part of the power management solution for an automotive device. The device is powered directly from the battery as follows (VBATT_FILT connects to VIN on the TPS51120):

I hoping for some guidance as to the level of EMI filtering/conditioning required by the TPS51120 in an automotive environment. I have surge/load dump (TPSMC20CA) and reverse polarity (RB088LAM-30TFTR) protection, but feel that some sort of common mode choke should be incorporated (located in the 'gap' in the schematic above). Would this be required for successful/optimal operation of the TPS51120? If not the TPS51120 itself, would the common mode choke (or an alternate filtering methodology) benefit the high/low side MOSFETs attached to the TPS51120?

The device is rated up to 15A, with an external 15A fuse on the power input cable. Any input would be greatly appreciated.

Thanks!

over 5 years ago

0 Sam(MPAA) Zhang over 5 years ago

TI__Mastermind 19080 points

Hi,

Yes, common choke can filter the common mode EMI, which makes it easier to pass the conducted EMI regulation(CISPR25 Class3/5 as automotive application you mentioned). A Pai-type EMI filter also works(usually has lower cost).

Hope the training video below can help,
training.ti.com/how-design-input-emi-filters-automotive-dcdc-converter

Please note that TPS51120 is not qualified for automotive grade, you may need to find a Q1 grade part for automotive application...

Any further question, please let us know.

Regards,
Sam

0 jars121 over 5 years ago in reply to Sam(MPAA) Zhang

Intellectual 605 points

Thanks Sam, I'm not sure how I missed that training video!

To confirm, the automotive grade applies to OEM designs requiring a particular AEC-Q1 certification? This device is an aftermarket product for the motorsport industry, so I don't believe the AEC requirements apply?

0 Sam(MPAA) Zhang over 5 years ago in reply to jars121

TI__Mastermind 19080 points

Hi,

What I mean was AEC-Q100 qualification.
I think you can check with your customer to see if they have the requirement to use Q grade part.

Regards,
Sam

0 jars121 over 5 years ago in reply to Sam(MPAA) Zhang

Intellectual 605 points

Thanks for clarifying Sam. In this instance, there is no requirement for use of Q grade parts. The TPS51120 satisfies all requirements/parameters, so should be suitable for this application.

0 jars121 over 5 years ago in reply to Sam(MPAA) Zhang

Intellectual 605 points

Sam,

If I were to use a Q1-grade dual (5V, 3V3) buck controller instead of the TPS51120, can you recommend a part? Would something like the TPS51220A-Q1 be a good option?

0 Sam(MPAA) Zhang over 5 years ago in reply to jars121

TI__Mastermind 19080 points

Hi,

I think TPS51220A-Q1 is good.

Regards,
Sam

Power management

Power management forum

TPS51120: Automotive EMI filtering