Posted by retromaster on August 26, 2009
I’ve completed the layout for the LCD daughterboard. Apart from the usual signal and power connections, I’ve implemented a simple, two-transistor 60ma constant current source for the backlight that is powered from the 5V available from the main board on the header. It may not be absolutely necessary though, since the LCD datasheet specifies a forward voltage drop of 3.2 to 3.4V for 60ma of current. The backlight would probably work fine when directly powered from the 3.3V rail.
Now, all that remains is to do some thorough final checking on both boards and hopefully move on to the manufacturing stage.