I am using WS2803 LED driver. I also got bunch of other stuff in my circuit, including standard Hitachi HD44780 LCD module. Now, when I turn on all 18 LEDs (I'm using 1.3k resistor on IREF pin), they all work, but suddenly I can't read anything on LCD display - backlight is still on, there's just no text. So, when all LEDs are off, display works just fine. But, as soon as I start lighting LEDs up one by one, I can read less and less on display until I can't read anything anymore. All of this suggests that LEDs cause significant voltage drop so I should use external power supply for LEDs. Questions:
1) Am I right? 2) If I am - well I don't actually want external supply, I'd like to use voltage regulator or something else, as long as I can power everything via USB, so I hope somebody can suggest me some solution.