DRV3901-Q1: Maximum voltage for 3.4A/0.5ms deployment

Folkert Roscam Abbing

Part Number: DRV3901-Q1

Tool/software:

Dear Sir, Madam,

Could you tell me if it is possible to activate a pyrofuse at 3.4A for 0.5ms at an operating voltage PVDD = 28V?

The numbers given in the datasheet of the part seems to suggest so, but I have my doubts if this is thermally achievable in a reliable way. Do you have any additional design info about this?

Thanks,

Folkert

2 months ago

0 Keerthivasan Kumanan 2 months ago

TI__Genius 13325 points

Hi Folkert,

Give me a day to look into this and get back to you.

Best,

Keerthi

0 Ibinu Alaudeen Nadeera 2 months ago

TI__Expert 7060 points

Hi Folkert,

Thanks for your question.

DRV3901-Q1 is capable of doing the high current deployment till VDRV_OV condition as shown below

Please let me know if this clarifies.

Thanks,

Ibinu

0 Folkert Roscam Abbing 2 months ago in reply to Ibinu Alaudeen Nadeera

Prodigy 60 points

Hello Ibinu,

Thanks. This does state the maximum VDRV. But it does not clarify what would be the thermal constraints. Let me explain by giving an example:

If the driver activates a pyrofuse at 3.4A, the voltage drop over a pyrofuse of 2Ω will be 6.8V. Add to that a bit to account for parasitic resistance in the circuit, say that the voltage drop over external components is 8V. At VDRV=25V, this leaves 17V drop over the driver.

17V at 3.4A is 57.8W, for 0.5ms (the deployment time). This is a lot of power for this package and I expect it to heat up quickly, thereby possibly exceeding the Thermal Shutdown threshold.

How can I design for not exceeding this threshold? I can consider the package thermal metrics, but I think that these are for steady-state and not for a single 0.5ms pulse. These would severely limit the allowable ambient temperature for this case (for example, take RθJC(bot)=1.3°C/W --> 57.8*1.3=75°C temperature rise, leading to 150-75=75°C max ambient temperature).

Do you have any additional design guidelines for this?

0 Keerthivasan Kumanan 2 months ago in reply to Folkert Roscam Abbing

TI__Genius 13325 points

Hi Folkert,

Give us 24 hours to look into this and get back to you.

Best,

Keerthi

+1 Ibinu Alaudeen Nadeera 2 months ago in reply to Folkert Roscam Abbing

TI__Expert 7060 points

Hi Folkert,

Thanks for clarifying the question.

You are right, the power dissipation will be high. However the transient thermal impedance will be much lower than the DC thermal resistance. You can assume <5% of the thermal impedance of DC for the 0.5ms case. Hope this helps.

Also, can you give me some details on what would be the actual application specifications, like Max VDRV and max ambient temperature.

Thanks,

Ibinu

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DRV3901-Q1: Maximum voltage for 3.4A/0.5ms deployment