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UCC28700-Q1: Primary AUX for regulation AND power supply?

Han asdf
Prodigy 30 points
Part Number: UCC28700-Q1
Other Parts Discussed in Thread: UCC28704, TIDA-01503

Hello,

We design a flyback power supply with primary side controller which uses the AUX winding of the transformer.

We have one question, is it possible to power primary side peripherals (controller etc.) with that AUX winding and still use it for output voltage control? Or will the load on the AUX winding disturb the functions of the primary side controller UCC28700-Q1?

Thank you!


Hannes

  • 0
    TI__Expert 8210 points

    Hannes

    Yes, you can use the aux winding to power a load (such as the UCC28700-Q1 controller) and use the same winding to regulate the output voltage.  The typical schematic in the UCC28700-Q1 datasheet implements this.

    You can even use the aux winding to drive an additional load as well.  TIDA-01503 is an example of this with UCC28704, which is a commercial grade device that has the same base control operation as UCC28700-Q1.  Please note that you need to have a blocking diode on both the VS and VDD pins to allow for proper operation.

    Best Regards,

    Eric