Thanks Bob, should work. Why pull down the pot input?

-Ishaan

Bob Ammerman wrote:

> Step 1: use a voltage divider with a ratio of say 1:13 from the output to
> ground. This can be a relatively high impedance divider, say 120K from +Vout
> to the midpoint and 10K from the midpoint to ground. The max voltage on the
> midpoint of this divider is now 1/13 * Max Vout = 1/13 * 55V = 4.2 volts
>
> Step 2: set up an op-amp as a voltage follower to reduce the impedance of
> the output of the voltage divider.
>
> Step 3: now use the output of the op-amp as the input to a 50K digital pot,
> with a small resistor to ground.
>
> Step 4: the output of the digital pot is your voltage feedback signal.
>
> Bob Ammerman
> RAm Systems

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