TPS62153: TPS62153 output to input protection

Samuel Lourenco

Part Number: TPS62153
Other Parts Discussed in Thread: TPS62152

Hi all,

I'm planning to use a TPS62152 and a TPS62153 on a small supply board to feed a breadboard. My question is if those DC-DC converters are inherently protected in case of voltage present at the output, which can happen if you have a big enough capacitance and you disconnect the supply, or should I add diodes from the output to the input of each converter? Since the internal switches are MOSFETS, and thus have a very small voltage drop, what kind of diodes should I add, if that is the case?

Thanks in advance.

Kind regards, Samuel Lourenço

over 7 years ago

0 Chris Glaser over 7 years ago

TI__Guru*** 147250 points

This app note, from the product page, discusses this topic in detail: www.ti.com/.../slyt689.pdf

If there is still a question, can you re-state it more specifically?

0 Samuel Lourenco over 7 years ago in reply to Chris Glaser

Intellectual 390 points

Thanks, Chris.

I was worried if a voltage on the outputs within the specs and equal or lesser to the set voltage could damage the DC-DC converters. But I'm guessing not. On the input side, I only have capacitors. A blocking diode at the input prevents the board from supplying other loads on the input side. So, I guess I have nothing to worry about, right?

Kind regards, Samuel Lourenço

0 Chris Glaser over 7 years ago in reply to Samuel Lourenco

TI__Guru*** 147250 points

It's still not perfectly clear what your setup is: do you have big caps on input or output or both?

But it is ok to remove the input voltage from the device. There will always be some output voltage left and this is ok--it will be sunk by the load or back through the input.

0 Samuel Lourenco over 7 years ago in reply to Chris Glaser

Intellectual 390 points

I have a 100uF polymer cap at the input, followed by two 10uF MLCC caps, one for each converter. Before that, I have a diode in series to prevent reverse polarity.

Anyway, your second paragraph answered to my worries. I guess that is more of a problem when using linear regulators, since those use BJT as pass transistors.

Kind regards, Samuel Lourenço

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TPS62153: TPS62153 output to input protection