INA300 eFuse

Andria Young

Other Parts Discussed in Thread: INA300, TIDA-00795

Hello,

I am working from the eFuse design using INA300. The alert signal does not pull low once the load current goes above the set load current. I am using a 7500ohm resistor at the limit pin to correspond to a 150mV reference voltage. However the voltage at this pin is 75mV. Also the voltage across the sense resistor is half of its expected value at a given load current. This would be fine since the Limit voltage is half of its expected value only the Alert pin does not trip when the voltage across the sense resistor is above 75mV.

I am using a 30mohm sense resistor and a maximum load current of 5A.

Could you please help with this problem? If you require information please let me know.

Thank you

over 8 years ago

0 Carolus Andrews over 8 years ago

TI__Mastermind 22650 points

Hi Andria,

Could you point me to the specific design you are working from? Thanks.

Carolus

0 Andria Young over 8 years ago in reply to Carolus Andrews

Prodigy 120 points

Hi Carolus,

I was working with this TIDA-00795. But I think I have solved this problem now. My other question was what happens if the Limit pins are accidentally stuck together.

Thanks,

Andria

0 Carolus Andrews over 8 years ago in reply to Andria Young

TI__Mastermind 22650 points

Andria,

I don't believe this will cause damage to the parts, but it will cause the equations to change, and ultimately is probably not a good solution. The LIMIT pins are equipped with 20uA sources that dictate the voltage across the LIMIT resistor, and therefore you will have an effective doubling of the current through the resistor.

Carolus

0 Carolus Andrews over 8 years ago in reply to Carolus Andrews

TI__Mastermind 22650 points

Andria,

After discussing it with the team, it doesn't look like this should be an issue, and even error may not be a problem. You just need to be aware of a few things:

- as I said earlier, the current passing through the resistor will be effectively doubled, so you will need to change the resistor value to half of what you would choose for a single amp to achieve the desired voltage level.
- the comparators will be bound to that same voltage, so you will lose the ability to choose different values for the two directions
- the comparators may still trigger at slightly different voltages due to mismatched internals of each INA300.

Apart from this it doesn't look like this should cause any damage to the parts. Hope this helps.

Carolus

0 Andria Young over 8 years ago in reply to Carolus Andrews

Prodigy 120 points

Thank you

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INA300 eFuse