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UCC21530-Q1: No charging pump capacitor application SCH review

Part Number: UCC21530-Q1

Hi Team,

My Customer decide to used the external aux winding voltage 18V  for VDDA & VDDB such as pic.

And he wonder to confirm the Vz voltage is decide this point negative voltage ?

another one is when Vgs_on is 18V then the Vgs_off is -Vz , Am I right ?

Did we have any EVM such as this application ? Could apply for them just one pcs ?

 Eddie 

  • Hello Chao,

    Thank you for reaching out on E2E.

    Using an isolated supply like this has some notable benefits over a bootstrap circuit, though it generally costs more. In the use you describe, an 18V supply applied from VSSA to VDDA with a zener diode as shown provides a Vgs_on of (18V - Vz) and a Vgs_off of (-Vz).

    Unfortunately, we do not have an EVM with negative turn off voltage. One option for the customer to understand this application is to implement it in a simulation.

    If this answers your question please let us know by clicking the green button, otherwise please let us know how we can continue to help.

    Regards,

    Daniel