TPS25942L: Latched after power on reset

Federico Silva

Part Number: TPS25942L

Hi,

I have a circuit that uses the TPS25942L as a circuit breaker with latch and my idea was in case of overcurrent, a power on reset was needed. However, I find that in case it latches unplugging the source is not enough, I need to force the EN pin to GND while the board is plugged. What is the supposed behaviour of the eFuse? According to https://e2e.ti.com/support/power-management/f/196/t/662869?tisearch=e2e-sitesearch&keymatch=tps25944, what I did should suffice.

Thanks,

Federico

over 6 years ago

0 Rakesh over 6 years ago

TI__Guru** 105361 points

Hi Federico,

Are you testing on EVM ? If not - can you please share the schematic?
TPS25942L will need reset at EN or Vin power cycle to restart the device.

Best Regards,
Rakesh

0 Federico Silva over 6 years ago in reply to Rakesh

Intellectual 795 points

Hi,

I realise the problem is actually the input voltage. I designed for it to cut-off at 20 V, but it latches off at 18 V. The weird thing is that there is an identical circuit on the other side of the board which works. All the resistors are 1% .

Thanks,

Federico

0 Rakesh over 6 years ago in reply to Federico Silva

TI__Guru** 105361 points

Hi Federico,

I did not see any issue in the schematic.

Coming back to your issue "in case it latches unplugging the source is not enough, I need to force the EN pin to GND while the board is plugged". Have you checked Vin, EN pin voltages when the source is unplugged? Is it coming to zero?
what is the load capacitance and load current just before the source is unplugged?

Best Regards,
Rakesh

0 Rakesh over 6 years ago in reply to Rakesh

TI__Guru** 105361 points

Hi Federico,

Did you get chance to do further test and probe ?

Best Regards,
Rakesh

0 Federico Silva over 6 years ago in reply to Rakesh

Intellectual 795 points

Hi,

I realised the problem was not the latch but the voltage I was using. With 18 V, one side of the circuit runs and the other doesn't; with 15 V both sides work. The thing is that both circuits are identical and the resistors tolerances are 1%, which shouldn't change much the thresholds according to my calculations.

Thanks,

Federico

0 Rakesh over 6 years ago in reply to Federico Silva

TI__Guru** 105361 points

Hi Federico,

Thanks for the update. Can you share the complete schematic. Are you using TPS25942L in power mux or ORing configuration?

Best Regards,
Rakesh

0 Rakesh over 6 years ago in reply to Rakesh

TI__Guru** 105361 points

Hi Federico,

Can you share the details to close this issue.

Best Regards,
Rakesh

0 Federico Silva over 6 years ago in reply to Rakesh

Intellectual 795 points

Hi,

I'm sorry for the delay. After some testing, I realised that there was a problem in the UV pin resistor, which was causing the problem.

Thanks,
Federico

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TPS25942L: Latched after power on reset