If you need some simple regulated power supply, you can build it using MCU and few external components:
PWM frequency 250kHz for max. output curent 500mA and supply voltage 12V with 100uH coil. Output voltage regulated from 0.3 to +SUPPLY-0.7V @Io=200mA. VCC and VOUT should be connected to MCU ADC in order to stabilize output voltage. Use low threshold MOSFET if driven from 3V MCU, logic level MOSFET if diven from 5V MCU.
Warning: output voltage referenced to +SUPPLY.