LM5050 reverse input protection

Jacky Chen29

Genius 4735 points

Hola,

I want to know about the part of reverse input protection as below：

Why below as Figure 25 which can provide reverse protection？thank you ～

over 9 years ago

0 Jacky Chen29 over 9 years ago

Genius 4735 points

Hola,
What's the function of D1 and D3 for？ can someone help to reply this question？Thanks ～

0 Alex Triano over 9 years ago in reply to Jacky Chen29

TI__Genius 12621 points

Hi Jacky,

This circuit provides reverse polarity protection by using D3 to protect the IC_GND in the case of VIN < chassis GND. When negative voltage is applied, the Q1 FET remains off, its body diode will not conduct and the IC will be protected by D3.

When performing a fast negative voltage transient on VIN, there could be a negative voltage spike across the IC's IN and IC_GND pins. D1 is used to clamp this negative voltage spike.

Thanks,
Alex

0 Jacky Chen29 over 9 years ago in reply to Alex Triano

Genius 4735 points

Hola Alex,
Clear and helpful. Thank you very so much.

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LM5050 reverse input protection