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UCC28780: UVLO threshold

Satoshi Yoshida
Prodigy 660 points
Part Number: UCC28780
Other Parts Discussed in Thread: LM5025, LM5026, UCC28C41, UCC2805

Hi HVC team,

Our customer is interested in UCC28780 and other TI products employing Active-clamp Flyback/Forword topology.
Their requirement is lower VDD turn-on threshold (UVLO) around 7 to 8V, so I cannot identify appropriate device in our portfolio.
(Unfortunately, VVDD(ON) of UCC28780 is 17.5V(Typ).)

Please let me know the alternative solution.
It’s preferable not only showing specific device ID but also reference design.
e.g. (in case of LM5025/5026) Do you have any idea to disable UVLO(VIN) and power-up from 7.6V(Vcc)?

Best regards,
Satoshi

  • 0
    TI__Expert 8210 points

    Yoshida-san

    LM5025 and LM5026 can start up and operate when an external voltage between 8V to 15V is applied to VCC, as specified in section 6.3 Recommended Operating Conditions of both datasheets.  PMP7895 is an example reference design with LM5026 where such a configuration is used.

    If LM5025 or LM5026 don't meet your customer needs, one of our single ended current mode PWM controllers like UCC28C41 or UCC2805 will work as well.  These devices have variants with UVLO turn on at and below the 7-8V range.  These devices will need an external circuit to generate the active clamp drive signal.

    Best Regards,

    Eric