Electronic Circuits and Projects Forum

Here's how I'd try to do it, assuming (a) +15V and -15V fixed supplies are available, (b) the digital pots have a maximum resistance of 100k each, and (c) independent control of the + and - adjustable supplies is required.
R1 and R4 are selected to prevent the digital pot voltage rising above ~ 3V, for compatibility with the micro controller .
U1 and U3 are unity-gain buffers. One can be omitted if a single pot is required to control both variable supplies so that they track each other.
U2 and U4 are respectively non-inverting and inverting amplifiers, each with a gain of ~ 4. The opamps need to be rail-to-rail I/O types if a wide control range is required.
M1 and M2 provide power gain. Feedback is taken from across the loads to stabilise the output voltages.

Can you tell me the current can be sourced by this circuit in worst case?

Many Amps, depending on the 15V supply and the FET ratings.

I also need to make sure a maximum current output of 500 mA for both the supplies.

I'll have a think about that and get back to you.

Also, do i need to add a short circuit protection?

That's for you to decide. But won't current limiting to 500mA provide that?

Here's the circuit with current-limiting. Even with a max 0.5A limit the FETs will get hot and will need substantial heat-sinks.

I will see the prices of the ICs you suggested

The ICs and FETs in the circuits I posted are just selections from the LTSpice simulation collection, chosen to suit the simulation. I'm not recommending any particular manufacturer. I haven't checked their package type, price etc. Many alternatives are available. Feel free to substitute other types.