TPS1685: E-fuse for low side battery negative

Gerard Cirera

Part Number: TPS1685
Other Parts Discussed in Thread: TPS1663, TPS2663,

Tool/software:

Hi,

We are looking for a way to protect the return line to our low voltage batteries (2x 12V 7Ah) in the scenario where the positive line is shorted to chassis and bypasses the protection we have on the high side.

An e-fuse would be a great solution but I am not sure if it is possible to use it on the low side, since the integrated MOSFET would see 0V rather than 24V at its input.

If we decouple the power input (IN) from the IC power supply (VDD) and power the IC from our other supply, can we use the e-fuse on the ground line back to the batteries?

Thank you for your help!

1 month ago

0 Kunal Goel 1 month ago

TI__Guru* 79181 points

Hi Gerard,

Did you check below devices?

Regards

Kunal Goel

0 Gerard Cirera 1 month ago in reply to Kunal Goel

Prodigy 45 points

What devices?

0 Amrit Jit 1 month ago in reply to Gerard Cirera

TI__Mastermind 31661 points

Hello Gerard,

You can check TPS2663,TPS1663.

What's your operating current?

Gerard Cirera said:
An e-fuse would be a great solution but I am not sure if it is possible to use it on the low side, since the integrated MOSFET would see 0V rather than 24V at its input.

Do you want the eFuse to operate at 0V? Not to turn off during that?

Thanks
Amrit

0 Gerard Cirera 1 month ago in reply to Amrit Jit

Prodigy 45 points

Current limit should be at ~20A continuous, 40A peak

We can power the e-fuse supply with another source so it will always have voltage, but we want it to interrupt a different power line on the low side, so the MOSFET will be at 0V drain and source

+1 Amrit Jit 28 days ago in reply to Gerard Cirera

TI__Mastermind 31661 points

Based on current rating TPS1685 is best option.

0V drain and source voltage is not an issue for eFuse. During that state do you want eFuse to be ON? It's OFF conation and you need power cycle to turn back ON

0 Gerard Cirera 27 days ago in reply to Amrit Jit

Prodigy 45 points

We want it to be operational yes, so that if there is an overcurrent it will detect and trigger.

+1 Amrit Jit 27 days ago in reply to Gerard Cirera

TI__Mastermind 31661 points

TPS1685 has min VIN of 9V. Device will be OFF if input falls below this value.

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TPS1685: E-fuse for low side battery negative