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questions about TPS65130

David Zhang16358
Expert 1860 points
Other Parts Discussed in Thread: TPS65130

I have implemented TPS65130 application based on page 9 of TPS65130 datasheet for generating +15V and -15V.

The values of R40 and R43 are wrong, the correct values for them should be 1.2Mohm around.

I have pulled both ENP and ENN to high to enable both positive and negative power regulators.

But TPS65130 is not working since all reference voltage, output voltage are zeros.

Pin 7, BSW, is pulled to zero and Q2 is conducted but the output voltage at drain of Q2 is +3.5V instead of +5V.

Please help what are the possible reasons for this?

 

Thanks.

 

  • 0
    TI__Guru 65470 points

    Hello David,

    So your design is based on the schematic on page 23 in the datasheet, is this right?

    Several values in the attached schematic are not within the recommended ones in the datasheet. Please change C67 to 10nF and C69 to 4.7nF as recommended on page 26 of the datasheet. I expect that the high values of 22uF keep the part from startup.

    In addition, you should recalculate the values of C133 and C132. 10nF seem to be very high for feedforward capacitors.

    Best regards,
    Brigitte

  • 0 in reply to Brigitte
    Expert 1860 points

    I have changed C67 and C69 to 10nF and 4.7nF; changed C132 and C133 to 6.8pF; changed R40 and R45 to 1.1Mohm.

    But the positive output is only +3.3V and negative output is only 0.23V.

    What are the possible reasons?

    Is it possible TPS65130 is damaged because of those previous incorrect settings?

    Thanks.

     

     

  • 0 in reply to David Zhang16358
    TI__Guru 65470 points

    Hello David,

    It is possible that the IC is damaged due to the wrong settings. Please try to replace it with a new one. In addition, it is important that the feedback resistors and feedforward capacitors as well as the compensation components are near to the IC. Layout is an important task with regulators that switch above 1MHz.

    Please have a look to the layout of the evaluation module (here you can find the document: http://focus.ti.com/general/docs/lit/getliterature.tsp?literatureNumber=slvu107c&fileType=pdf).

    It would also be intersting to see if one of the converters is able to start, if the other one is disabled.

    Best regards,
    Brigitte