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Original question:

UCC29910A: VBULK

UCC29910A: Current of VTB

Takahiro Sugiyama
Prodigy 30 points

Part Number: UCC29910A

Tool/software:

In Schimatic of  UCC29910A-730, there is aport named "VTB".

How much current flows through this VTB node?

If the current is small, it seems possible to provide a Valley-Fill circuit without using a transformer and obtain current from the generated DC potential.

The goal is to keep the module height low.

  • 0
    TI__Mastermind 40580 points

    Hello Sugiyama-san, 

    I don't know how much current flows from the VTB node, but the average current supports the bias currents of U1, U2, U3 and the gate-drive current of Q5 MOSFET. 
    The datasheets of each device can be reviewed to determine these currents and sum them up, plus a little more for design margin. 

    I estimate probably less than 20mA. Maybe this is small enough for a Valley-Fill circuit to provide, to simplify the buck inductor design. 

    Regards,
    Ulrich

  • 0 in reply to Ulrich Goerke
    Prodigy 30 points

    Hellow Ulrich-san

    Thank you for your reply. I will look into this further.