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LM2991: Inquiry about DC/DC converter recommendation that supports negative voltage

JH Shin
Mastermind 8160 points
Part Number: LM2991
Other Parts Discussed in Thread: TPS40210, TPS61086, TPS61170, TPS61175

Hello,

My customer is looking for DC/DC products that can be used for the following conditions.

  - VIN = -15V, VOUT = -6V, IOUT = about 300mA(typ) : Best if it can support up to 1A

They prefer DC/DC products over LDO to reduce heat generation. Additionally, due to space constraints, the smallest package size is required (less than 4 mm in height).

Please recommend which of TI's DC/DC products best suits the customer's requirements.

Thank you.

JH

  • 0
    TI__Guru 51475 points

     

    I will try to find the right resource to help you with a -15V to -6V Negative-to-Negative converter.

    To build a Negative to Negative converter, you'll need a boost controller or converter.  Here is a refeence design based on the TPS40210, which does -18 to -3.3, which could be updated to a -6V output.

    Here is an applications note about it - https://www.ti.com/lit/pdf/slvaf68 though, with the input voltage limited to 18.5V, the TPS61086 might not be the right product for your 15V input needs, but the application note will.

    I will try to get this over to someone in our boost converter team to help you find the best part for your needs.

  • 0 in reply to Peter James Miller
    TI__Mastermind 46951 points

    Hi JH Shin,

    please have a look at this reference design.

    This will be a good starting point for your design:

    PMP9624 reference design | TI.com

    Best regards,

     Stefan

  • 0
    TI__Genius 10880 points

    Hi JH,

    The boost device TPS61170 should work in VIN = -15V, VOUT = -6V, IOUT = about 300mA(typ) and up to 1A.

    I'm doing the simulation to verify the solutions now and will get the feedback to you asap.

    And you may also check the reference design that Stefan posted in parallel.

    Regards

    Lei

  • 0
    TI__Genius 10880 points

    Hi JH,

    I verified that TPS61170 can work in VIN = -15V, VOUT = -6V, IOUT = about 300mA(typ). Well, the max Iout at this condition is around 600mA.

    To support the 1A Iout, TPS61175 can be the choice.

    Regards

    Lei