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LM43601: Negative output issue

Expert 2490 points

Replies: 5

Views: 120

Part Number: LM43601

Hi TI,

I have designed -5V Inverter design based on Webench simulation. But It's not working(No output).

This issue is solved when I removed the capacitor is from VIN to VOUT (Cio) or reduced to under 0.1uF 

Load current is under 100mA.

Please let me know about the reason.

The voltage rating of Cio is over 25V.

  • Hi Mason,

    What's the input voltage range so we can verify the Webench design?

    Normally Cio 0.1uF is good enough for this topology.

  • In reply to Andy Chen:

    Hi Andy,

    Input voltage is 5V.

    If Cin value is too large, can it not work?

  • In reply to Mason Noh:

    Hi Mason,

    Cio and Cout Pls will divide input voltage, if Cio is too big, LM43601 may see high enough voltage for startup.

    Pls measure voltage between Pin13/14  and Pin15/16 by oscilloscope at Vin turn-on, it should be higher than 3.8V for chip startup.

  • In reply to Andy Chen:

    Hi Mason,

    Pls ignore above reply.

    Cio and Cout will divide input voltage, if Cio is too big, LM43601 may NOT see high enough voltage on Cio for startup.

    Pls measure voltage on Cio by oscilloscope at Vin turn-on, it should be higher than 3.8V for chip startup.

  • In reply to Andy Chen:

    Hi Andy,

    Thank you for your kind support.

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