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CONSTANT CURRENT SOURCE

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CONSTANT CURRENT SOURCE

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afzal alam
Posted by
on Feb 10, 2012 3:25 AM
Prodigy50 points

I am new in field of electronics , my job is to design 100 mAmp constant current source. I find the Texas Ic LM5019 . Plz suggest me this is suitable or there is another model which i can use.

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  • CWilson
    Posted by
    on Feb 10, 2012 3:32 AM
    Expert1060 points

    What input voltage?

    If you're under 37V I suggest a LM317 coupled as a constant current source. It's cheap and quick.

    Iout = Vref / R ==> 0,1 = 1,25/R ==> R = 12.5 Ohm.
    Power dessipated in the resistor is 0,13W. (Use at least a size SMD 1206 resistor (250mW) for the power loss in resistor)

    Page 18: http://www.ti.com/lit/ds/symlink/lm117.pdf 

    Figure: 906316. 

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  • afzal alam
    Posted by
    on Feb 10, 2012 4:11 AM
    Verified Answer
    Verified by
    Prodigy50 points

    Dear Sir 

    Thanks for your reply

    My input voltage is 5V (output of 7805). I have one more problem previously i design this constant source with using 47 ohm 1W resistor ,100 ohm POT  and L7805CV voltage regulator . problem is that L7805cv is too hot also resistance

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  • afzal alam
    Posted by
    on Feb 10, 2012 5:59 AM
    Prodigy50 points

    Dear Sir 

    Thanks for your reply

    My input voltage is 5V (output of 7805). I have one more problem previously i design this constant source with using 47 ohm 1W resistor ,100 ohm POT  and L7805CV voltage regulator . problem is that L7805cv is too hot also resistance

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  • CWilson
    Posted by
    on Feb 10, 2012 6:02 AM
    Expert1060 points

    What was your input of the 7805?

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