TPS25927: Dual rail protection

Federico Silva

Part Number: TPS25927

Hi,

I have a circuit which, in case of failure or overcurrent, needs both Vcc and GND to be disconnected at the same time. I've been looking around and haven't found anything similar. The possible solution I thought of is an e-fuse with an external fet to disconnect the ground, like the one below.

Would this work?

Thanks,

Federico

over 7 years ago

0 Rakesh over 7 years ago

TI__Guru** 105361 points

Hi Federico,

I am not able to view the image. Can you please re-send the image.

Best Regards,
Rakesh

0 Rakesh over 7 years ago in reply to Rakesh

TI__Guru** 105361 points

Hi Federico,

This will work. Can you please share the application use case details.
The BFET pin voltage will be Vin + 6.4V. What is the max. voltage of Vin? Make sure BFET voltage does not exceed rated Vgs of the external FET.

Best Regards,
Rakesh

0 Federico Silva over 7 years ago in reply to Rakesh

Intellectual 795 points

Thanks for the answer Rakesh,

the input voltage would be 16 V, so yes, that would most likely exceed the max Vgs of the FET. BFET is a charge pump capable of drawing 2 µA, right? If so, a voltage divider would do the job (with a high enough total resistance, of course).

Regards,
Federico

0 Rakesh over 7 years ago in reply to Federico Silva

TI__Guru** 105361 points

Hi Federico,

Instead of resistor divider, I suggest to place low leakage 15V zener diode (something like BZX84C15LT1) between GATE to Source of the FET.

Best Regards,
Rakesh

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TPS25927: Dual rail protection