Simple voltage inverter with mosfet/bjt
You only have 3 active switches ( 1 FET 2 diodes and a 100R resistor ) instead of 4.


This is the ideal circuit. and ESR of switch and caps is key to your requirement with Load regulation error being 1V/@15mA = 67 Ohm  The ESR of 3.3V 74ALSxxx drivers are 22~33 Ohm for example.