Power IR2110 from a low voltage AC Source

I am trying to power the IR2110 using an AC Source. However, this source is also connected to a full wave bridge rectifier that’s going to supply a controlled buck converter.

I tried using a voltage quadrupler that takes a 5V sine from a function generator as input to and outputs around 16V DC. I thought that by adding regulators I can get the required voltages to supply the IC. I am still confused about which point to connect as ground to the regulators. I tried using the ground of the rectified output as the reference point in my whole circuit. I also tried simulating the attached circuit using LTSpice but the simulation was too slow and couldn’t be completed.

The problem is that the 15V regulator outputs only 6V. By tracing the circuit I found out that the multiplier output drops whenever the regulator is connected to the circuit. How can I solve this problem? And are there better ways to power this IC from an AC source ? I would really appreciate your help 🙂