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UCC21710: Deriving a 3.3V from UCC21710 output

Prahaladh S
Intellectual 300 points

Part Number: UCC21710
Other Parts Discussed in Thread: AMC1302

Hi...

We're planning to use UCC21710 in our application. We're getting the supply from UCC14141 to get a 15V & -4V for the gate driver. We have a 15V supply, that we're planning to as input to UCC14141.

Now, the requirement is to have an isolated 3V3 supply. 

Can we take the output of UCC14141 (15V) & generate the 3V3 through an LDO ?

If so, need to understand on the GND to be considered.

As the UCC14141 is preferred for floating GNDs to drive the H-bridges, we need further clarity.

Kindly guide us in this regard.

Best Regards,

Prahaladh S

  • 0
    TI__Expert 3267 points

    Hi Prahaladh,

    To further assist you, can you please share what you want to use the 3.3V supply for. Are you trying to use the 3.3V rail as pull-up reference for your AIN pin?

    Best rgards,

    Muiz.

  • 0 in reply to Muiz Ishola
    Intellectual 300 points

    Dear Muiz,

    Thank you for your response.

    We're using 3V3 supply to power AMC1302. Around 20-30 mA, load current is required at 3.3V rail.

    Kindly suggest if we can generate 3V3 from output of UCC14141.

    Best Regards,

    Prahaladh S

  • 0 in reply to Prahaladh S
    TI__Expert 3267 points

    Hi Prahaladh,

    Yes, you can generate the isolated 3.3V rail using an LDO from the 15V output of UCC14141. You would use the secondary ground of the UCC14141 as the reference for both the LDO and the AMC1302. This is the same ground used by the UCC21710 and is typically tied to the source/emitter of the power module.

    I would also like to highlight that the gate driver supply experiences high dv/dt so sharing this supply with the AMC1302 can inject switching noise into your measurement path, so you would likely need to integrate some additional filtering to your system.

    Best regards,

    Muiz