Hi all,

I need some help here . I have a project with a PIC18F4550 that uses USB interface to communicate with a PC. Also, the PIC interfaces with a color GLCD and an SD card. I'm planning to use a rechargeable battery. I have three different voltage level requirements for this project. The voltage levels that I need are as follows
  • 3.0V for the GLCD Vin and I/O ports, and also for the SD card.
  • 5.0V for the USB interface.
  • 12.0V for the GLCD backlighting. The backlight voltage feed uses a 220 Ohms resistor in series.

I would like to keep the circuit as simple as posible with a minimum number of components. That is why I would prefer not to use two voltage regulators, 3V and 5V.

What is the best way to do this? Can I run the PIC at 3.0V and use a level converter for the USB interface on D- and D+? How do I go up to 12.0V for the GLCD backlight? What chips can I use?

Thank you for your help.

Robert