TPS563209: Reverse polarity behaviour and protection

Patrick Felstead

Part Number: TPS563209

Hi there, what will the converter IC do if power is applied in reverse polarity? If it will malfunction or fail, what is the best way to protect?

I am using the reference EVM design PCB layout for a Vin of 12V (automotive) and output of 5V at approx 2.5Amps.

If reverse polarity protection is required, would a simple diode on the output stage after the feedback resistor work ok?

Thank you

over 4 years ago

0 Zhao Ma over 4 years ago

TI__Genius 15135 points

Hi, Patrick

Confirm with you: Vin power is reverse polarity?

0 Patrick Felstead over 4 years ago in reply to Zhao Ma

Prodigy 40 points

Hi, yes if the end user accidentally reverses Vin (+ and GND are swapped). This is because I am using a 2.1mm DC barrel jack connector which could be reversed by mistake.

0 Zhao Ma over 4 years ago in reply to Patrick Felstead

TI__Genius 15135 points

Hi, Patrick

Actually, the Vin pin has ESD protection devices, see below.
When Power is reverse polarity, the current will flow through D5 from GND to VIN.

Usually, D5 can bear ~1A, under this condition, IC will not failed or damaged.

However, I still suggest to place diode between Vin and GND as body diode, which can provide reverse polarity protection.

0 Patrick Felstead over 4 years ago in reply to Zhao Ma

Prodigy 40 points

Hi Zhao, thanks that helps to know about the internal D5 diode which is part of the ESD protection.

Can you please clarify where to place diode for protection? Wouldn't it be better to place a diode inline before the Vin pin?

0 Zhao Ma over 4 years ago in reply to Patrick Felstead

TI__Genius 15135 points

Hi, Patrick

Yeah, you are right.

I think the series one diode between power supply and IC's Vin pin is good, which can provide reverse polarity protection.

0 Patrick Felstead over 4 years ago in reply to Zhao Ma

Prodigy 40 points

Thanks!

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TPS563209: Reverse polarity behaviour and protection