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UCC28089: Alternate part availability or method to operate existing part at VCC 9VDC

Steven Fryette
Prodigy 250 points
Part Number: UCC28089
Other Parts Discussed in Thread: UC3525A, UC3527A, UCC2808-2, UCC28084

I've been experimenting with the UCC28089 as a simple unregulated P-P converter. So far so good.

Now I want to refine the supply Vin, currently at 12VDC and would prefer 9VDC. Currently, I can manually start the device at just over 10V and then drop it down to 9, which seems to work fine.

I could use the LT1054CP as a positive voltage doubler using a Zener to limit input to 6VDC, but that seems clunky.

I've been unable to find a device similar to the UCC28089 with a VCC of 9V or less.

Is there such a device, or is there a more elegant, simple way of fooling the UCC28089 into starting up with a supply Vin of 9VDC?

Thank you! 

  • 0
    TI__Mastermind 31580 points
    Hi Steven,

    One of our application engineers will be in contact with you shortly.

    Regards

    Peter
  • 0
    TI__Expert 3200 points
    Steven,

    I am asking an AE for a second opinion but it is going to be hard to recommend an 8-pin UCC28089 equivalent to operate at the lower Vin which has a max start threshold of 10.5 V. If the start threshold is the only consideration, maybe the UC3525A or UC3527A could work, start threshold max is 8 V. To continue using the UCC28089, will need a boost converter.
  • 0 in reply to Brian Johnson96
    Prodigy 250 points
    Brian,

    Thanks for the quick response.
    While you're waiting for a response from your AE, allow me to impose some additional limitations:

    1) In the same cost range s the UCC28089
    2) OSC frequency in the range ot 100-150KHZ

    I had already researched the possibility of using a boost converter and found no cost or performance benefit of doing so compared to my LT1054CP soultion, which is already an inventory part and cost effective, requires no inductor, etc.

    Thanks again and await further info.

    Steven
  • 0
    TI__Intellectual 2230 points
    Hi Steven,

    Would you consider the UCC2808-2 or UCC28084/6 which are similar devices (not functional equivalent) with lower UVLO thersholds(4.3V)?

    Thanks
    Oliver
  • 0 in reply to Oliver Pan91
    Prodigy 250 points
    Hi Oliver,

    If by functionally equivalent you mean pinout, or form factor, that's OK.
    I just want to use it the same way I'm using the 28089 - without flyback, current sense, etc.
    I just need the P-P mosfet drive and 100KHZ operating frequency.
    Currently driving a pair of BSS316N mosfets.
    The goal is to have an operating range at Vin of 9-12VDC, rather than being married to 12.
    With Vin 12VDC (regulated), I've got 20V p-p. With 9VDC(also regulated), I'll be at around 15V p-p.
    Max current draw at Vin 12VDC is 200 -300mA.

    Thanks,

    Steven