TPS2491: DC surge test output shutdown

Hi Keong, During surge test, the fast rising transient voltages generate huge transient current from input to output. This would trigger fast current trip and shuts down the device. Can you share your application and end equipment? Is it acceptable to use protection on the return path? Best regards, Rakesh

Hi Keong,

During surge test, the fast rising transient voltages generate huge transient current from input to output.  This would trigger fast current trip and shuts down the device.

Can you share your application and end equipment? Is it acceptable to use protection on the return path?

Best regards,

Rakesh

HI Rakesh,

Thx for your explanation. My end equipment is connected to a digital/RF board. 

I have tested with either this board alone or connected to end equipment, both will have output shutdown issue.

Do you mean add a diode on the 48V_RTN_I to TPS2491 gnd pin for protection?

FYI, surge test have cover polarity +ve and -ve, both i found output will shutdown.

Hi Keong,

To support surge events, the solution should have following

1. back-to-back FETs
2. reverse polarity protection
3. reverse current blocking
4. Fast GATE drive to recover quickly after the surge event

Something like http://www.ti.com/lit/ds/symlink/tps2663.pdf. What is your max load current ?

The other option is TPS23523 controller on the negative power path.

Best regards, Rakesh

Hi Keong,

Do you have any follow up questions.?

Best regards, Rakesh

Hi Rakesh,

   Design max load ~15A. Efuse not suitable for my application. 

FYI, previous revision PCB don't have surge issue but this new spin PCB have. On new PCB, TPS2491 have location change and big layout change. But all component value remain same.

So from your explanation, during surge, huge current flow thru sense resistor to charge the output cap and trigger OCP.

I still figure out how to minor tweak to solve this issue as no layout change allow.