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MC33063A: quiescent current data in inverting buck-boost mode

Wiky Liao
Intellectual 1800 points
Part Number: MC33063A
Other Parts Discussed in Thread: TINA-TI

Hi Team,

May I have the tpyical quiescent current of MC33063A when configure to inverting buck-boost mode? We don't add any load at output however the quiescent current will be abut 50mA, that's too high. We try to change current limit resistent however it still get the same result.

I also try to simulate by TINA-TI, but the quiescent doesn't be moduled.

Vin: 5V

Vout: -12V

Iout: less than 1mA

  • 0
    TI__Mastermind 23400 points

    Hi Wiky Liao,

    thank you for your question.

    The electrical characteristics of the MC33063A list an overall supply current of max. 4mA, which should also apply for an operation with no load. (Page 5 of the datasheet https://www.ti.com/product/MC33063A )
    Like you already said, a quiescent current of 50mA is definitely far more than expected.
    Therefore, I would assume that the leakage is coming from other external parts of the circuit.

    Is the first schematic you sent also the one used for your measurements? Otherwise it would be helpful to look at the full schematic to find out where the large amount of leakage might come from.

    Best regards,
    Niklas

  • 0 in reply to Niklas Schwarz
    TI__Intellectual 1800 points

    Hi Niklas,

    thanks for your comments. The first schematic is the one we measured. We are deep checking customer board to see if any leakage. Will let you know further support. thanks. 

  • 0 in reply to Wiky Liao
    TI__Mastermind 23400 points

    Hi Wiky Liao,

    I hope you have found the source of the leakage in the customer board.
    I will close this thread for now, as there are no additional comments.

    If you have further questions or need more help in analyzing the board, feel free to comment below to re-open the thread.

    Best regards,
    Niklas