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  1. #1
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    Regulating without load

    Hi all,

    I am debugging a board with the IC ( regulator ) NCP3063 and I am not quite sure if it would regulate or not if I removed the load. It is a current peak sense, if there is not current flowing would it just opening the gate of the internal transistor and then not regulate any voltage?. I would like to test it without load, but I need to be sure that I can check if it would work with load and without load.

    Thanks,
    Winsu

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    Re: Regulating without load

    Hi,

    It depends what you call "regulate".
    Without load, there will be output voltage..so it does regulate somehow.

    But there will be no continous switching. Rather burst mode or with greatly reduced switching frequency.

    We don't know anything about your circuit...if it is step up or step down, no input voltage, no output voltage .... and so on.
    The same incomplete will our answers be.

    The peak current is not the peak load current. It is the peak current of the internal switch.
    Even without load there still should be the inductance and the output capacitor and the input capacitor (but we don't know for sure).
    But if so ... there can be peak switching current.

    Klaus
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    Re: Regulating without load

    at start up with no load these simple bang-bang reg's can go over volts and sit there for a long time until the leakage current on the electro brings them down ...

    a 150k resistor from the output switching node to the timing cap makes them run much more stably ...



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    Re: Regulating without load

    I have been trying to test it without load,without electrolytic capacitor at the output and without a Mov that I had at output in case it went above the regulation value ( because the electrolytic capacitor at the output is rated 10V, so if it doesn't regulate it would go bang and the Mov would clamp above 5V). I don't know if by removing the electrolytic capacitor the regulation would not take effect...... The resistor to set the voltage has the values to output 4.5V.



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    Re: Regulating without load

    Hi,

    Don't use a switch mode regulator without output capacitor.
    Depending what type it is it could immediately kill itself.

    Read the datasheet, it shows the minimum circuit required to operate properly.

    Klaus
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  6. #6
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    Re: Regulating without load

    I have been trying to test it without load,without electrolytic capacitor at the output
    as Klaus says, the above is a very bad idea, get some help from some one who has some experience in power electronics ...



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  7. #7
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    Re: Regulating without load

    I fitted today the electrolotyc capacitor and I changed the regulator, it is regulating now, thanks


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