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TPS5430: TPS5430 Output -12V

wenxing zheng
Prodigy 50 points
Part Number: TPS5430

Hello,

Our design needs 24V input and -12V@0.5A output by TPS5430.

1. Can we get the related parameters, L,Co.etc,by TI's WEBENCH? 

2. If ENA floated,TPS5430 can work?

3. If ENA is controled by MCU's GPIO, what is the level of ENA,it relates GND or -12V?

Thanks!

  • 0
    Prodigy 50 points

    Hello,

    Our design has other application of TPS5430, 24V input and 3.3V@0.5A output.

    Design by WEBENCH, as below.

    The L1 and Cout will burn when the vin input 24V.

    The L1 is CLF7045T-680M-D,68uh@MAX DC=1.1A,Cout is T520B157M006ATE070, 6.3V and esr=210m ohm.

    As below,the 3.3V output hasn't load and supply 24v to vin,the result is L1 and Cout will burn.

    Thank !

  • 0 in reply to wenxing zheng
    TI__Guru 57555 points

    Hello

    Regarding the inverting design.  We don't have a Webench set-up for inverting for this device.

    However, there is a reference design for an inverting topology on the product page that you can test with TI SPICE.

    Also, I have attached an app note that may be helpful.

    Regarding the 3.3Vout design.  Please provide waveforms of the PH node, the VIN node, and the output voltage during your testing.

    Also, provide images of your PCB layout.  

    How are you starting-up the device ??  Through VIN or EN ??

    Your inductor should be rated for the current limit of the device, regardless of your maximum load current requirement.

    Try an inductor with a larger current rating.

    I will assign this post to the application engineers responsible for this device.

    Thanks

    5265.snva856a.pdf

    UnderstandingBuckBoost.pdf

  • 0 in reply to Frank De Stasi
    Prodigy 50 points

    Hello,

    Thank your suggestion.

    About 3,3Vout,

    How are you starting-up the device ??  Through VIN or EN ??

    EN is floated,no external control.

    Your inductor should be rated for the current limit of the device, regardless of your maximum load current requirement.

    That means our inrush current will over it? the inductor is selected by WEBENCH.

    Thank you!

  • 0 in reply to wenxing zheng
    TI__Prodigy 260 points

    Hi there,

    Webench designs for a buck implementation. Using this as a buck-boost will result in a bigger ripple current and will therefore need a bigger inductor. The app notes previously attached by Frank will be the best guides to alter your design for an inverter/buckboost implementation. 

    Hope this helps. 

  • 0 in reply to Nicole Lemieux
    Prodigy 50 points

    Hi，

    Thanks your help!

    In our design,we have 24v input and 3.3v@0.5A output,buck  implementation. 

    All components are selected by webench,but as previously description,the L and Cout will burn after input 24V.

    That means we should select L that has more bigger current than webench ?

    Thanks!

  • 0 in reply to wenxing zheng
    TI__Prodigy 260 points

    the output is 3.3V or -12V? 

  • 0 in reply to Nicole Lemieux
    TI__Prodigy 260 points

    Try a different inductor with a larger current rating, as a test. 

    See if you can take SW and Vout waveforms at some input just before it gets damaged.