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Electronics => Projects, Designs, and Technical Stuff => Topic started by: evansg on October 31, 2019, 10:21:20 pm

Title: How to prevent voltage at output of TPS54302 to feed circuit input?
Post by: evansg on October 31, 2019, 10:21:20 pm

I need your help guys,

I have designed the circuit below with the TPS54302 regulator.
What happens is that if someone accidentally applies voltage to the output (Let's say 12V) the input receives the same 12V and provides voltage to any other component in the 12V input line.
I have seen cases that a user accidentally plugs the 12V (circular 2.1mm socket) into the regulator output (which has same 2.1mm socket). I want to keep the 2.1mm circular socket so replacing the output socket with another type is not an option.

What is the best way to prevent this? Maybe by using a n type mosfet at the output? Any better solution?

Title: Re: How to prevent voltage at output of TPS54302 to feed circuit input?
Post by: thm_w on October 31, 2019, 10:55:40 pm

Sorry but thats just a bad design if the input and output are using the same connector.

You didn't specify what sort of current, but it doesn't look to high, so a schottky diode on the input or output would be an option. On input you'd need to figure out if switcher is damaged at all when backfed, if output you may need to adjust the voltage up a bit from 8V.

Title: Re: How to prevent voltage at output of TPS54302 to feed circuit input?
Post by: evansg on November 01, 2019, 08:59:47 am

Seems that It does not harm the switcher. Output is 2Amps at max. I am trying to place a reverse n-mosfet at the 8V output  but still experimenting with that.