LM74610-Q1: Reverse Polariy Protection

Fabio Soriano

Part Number: LM74610-Q1
Other Parts Discussed in Thread: LM5050-1-Q1, LM5050-1

Hi Team,

I received the below request, can you help?

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We did the reverse polarity test. We used LM74610-Q1 for this. But the current flows through the IC. The voltage of gate and source are equal.

The circuit diagram is as follows. Where did we go wrong?

And our scheme starts with pi type filter and continues with reverse polarity protection – TPS65381 – DRV3201. Thank you for your help.

over 5 years ago

0 Karikalan Selvaraj over 5 years ago

TI__Genius 16305 points

Hi

Reverse current is not expected to flow when the Gate - source voltage is zero, unless the IC is damaged.

Can you let us know how much reverse current is flowing?

Also what is the reverse voltage and nominal working voltage you are using this device?

Regards,
Kari.

0 TUGCE KUMRU over 5 years ago in reply to Karikalan Selvaraj

Prodigy 60 points

Hi,

The short-circuit protection is 6 A, so we see 6 A. Normal operating voltage is between 16 and 32 V. The applied reverse voltage is -24V.

Regards,

Tuğçe

0 Karikalan Selvaraj over 5 years ago in reply to TUGCE KUMRU

TI__Genius 16305 points

Hi,

Operating voltages are within the recommended range, so no issue of IC getting damaged.

Could you let us know the TVS rating used at the input, only other way the reverse current could flow is through the TVS or any other component across IN-GND.

Can you share the input portion of the schematic?

Regards,
Kari.

0 TUGCE KUMRU over 5 years ago in reply to Karikalan Selvaraj

Prodigy 60 points

Hi Kari,

We used SM8S43AHE3_A/I.

Regards,

Tuğçe

0 Karikalan Selvaraj over 5 years ago in reply to TUGCE KUMRU

TI__Genius 16305 points

Hi

We don't see any issues with the input protection.

To further help to resolve, can you please send the board to us for testing?

Regards,
Kari.

0 TUGCE KUMRU over 5 years ago in reply to Karikalan Selvaraj

Prodigy 60 points

Hi Kari,

I don't understand exactly what you want. You want our full scheme, or do you want to send you the PCB?

One more thing. I want to use LM5050-1-Q1 for reverse polarity protection. What’s your suggestion for this topic? Our circuit 24V, 70A. Is it a problem?

0 Karikalan Selvaraj over 5 years ago in reply to TUGCE KUMRU

TI__Genius 16305 points

Hello Tugce,

If you can share full schematic, we will try to see if we are missing anything here.

For reverse polarity protection using LM5050-1 please refer to the TI design "www.ti.com/.../TIDA-00992".

Regards,
Kari.

0 TUGCE KUMRU over 5 years ago in reply to Karikalan Selvaraj

Prodigy 60 points

Hello Kari,

I can not share full schematic, thank you for your help.

And, again thank you for your suggestion.

0 Karikalan Selvaraj over 5 years ago in reply to TUGCE KUMRU

TI__Genius 16305 points

Hi

I have hooked up the EVM and tested the configuration and it works fine, no reverse current.
If you are not willing to share the full schematic online, could you share only the relevant portion of schematic over email "karikalan@ti.com"?

If you think this has answered your question, please click " this resolved my issue "button.

Regards,
Kari.

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LM74610-Q1: Reverse Polariy Protection