MP2460: negative Vin/Vout differential withstand

DC-DC Power Converters
1

Hello MPS,

we are using the MP2460 step-down converter IC in our application to convert approx. 36-40VDC to provide a regulated 24 VDC rail.

The application is very similar to the example mentioned in the datasheet pg. 20 (shown below), except in our case the output voltage is set to 24V.

kuva
kuva1991×976 79.6 KB

I’m concerned about what happens if Vin dips down to 0V while the output cap is charged at 24VDC. Will the part be damaged?

Another scenario: what if there’s an external voltage surge that charges the output cap up to 45V?

Would you recommend to fit a backwards-connected diode between the Vin and Vout (or Vin and SW?) nodes to limit the voltage difference between input and output?

Looking forward to your advice. Thank you.

2

Hi @arttu.rasanen ,

If there’s a Vin failure (short, etc.) while the output caps are charged, then reverse biasing through the internal body diode is a very real circumstance to look out for. I recommend placing an external diode (anode to cathode) from SW to Vin and GND to SW and thoroughly test your edge cases.

Same applies to if an external voltage surge charges the output cap to 45V.

Thanks,
Rubas