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Lt3042, LT3045 Vout set by DAC

I need to adjust output voltage in the small range (i.e. with Vout nominal =20V, Vout adj = 15-20V as an example).

What would be the best way to do it with hardware preset voltage at eithe low or high end and DAC output to make an adjustments.

Thank you,

Nikolai

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  • The challenge with using LT3042/5 is that the SET pin voltage rises to the same level as the OUT voltage. If the adjustment range is too large, then you will end up needing devices with higher voltage ratings.

    Two possible approaches I've used before in personal projects are implementing a resistor divider to be used with either (1) a current DAC (like LTC7106) or (2) a digipot (like AD5272). The advantage of the digipot is the simplicity, while the advantage of the current DAC is advanced control (like slew rate).

    Here's a brief simulation of how the current DAC would work to make an output from 15V to 20V.

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  • The challenge with using LT3042/5 is that the SET pin voltage rises to the same level as the OUT voltage. If the adjustment range is too large, then you will end up needing devices with higher voltage ratings.

    Two possible approaches I've used before in personal projects are implementing a resistor divider to be used with either (1) a current DAC (like LTC7106) or (2) a digipot (like AD5272). The advantage of the digipot is the simplicity, while the advantage of the current DAC is advanced control (like slew rate).

    Here's a brief simulation of how the current DAC would work to make an output from 15V to 20V.

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