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[SOLVED] changing voltage for LDO

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Paul GRIM

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Hi all,

I use this LDO in my design for filtering low frequency output noise.
I would like to change the output voltage of this LDO by the DAC.:drevil:
LDO.PNGLDO.PNG
The output of the DAC range (0-3.3V)
The output of the LDO range (0-10V)

Have you an idea how i can design this ldo ?

Thank you for your help !

Paul
 

ArticCynda

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The feedback pin will servo to a certain internal reference value, usually 1.23V or 0.8V for low voltage types.

Wat you could do is to compare the a third of the LDO output (10 / 3 = 3.33...) to the DAC output with an opamp comparator, and then send this signal to the feedback pin instead. A low noise, rail to rail opamp like the LMV321 is recommended.
 

Paul GRIM

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Hi ArticCynda,
thanks for your answer
the internal reference of this ldo is 1.25V typ

compare the a third of the LDO output (10 / 3 = 3.33...) to the DAC output with an opamp comparator, and then send this signal to the feedback pin instead
Can you clarefy your idea please !
this is my shematic !
LDO.PNG

Paul
 

Paul GRIM

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hi
i underestand your idea
Thank you for your help

Paul
 

ArticCynda

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Glad I could help, good luck!
If your problem is solved, please don't forget to mark the thread as [solved].
 

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