I am trying to design a clock with a big 8-digit 7-segment display formed by about 250 LEDs, but with a power draw limit of 1A from a 5V USB phone charger. Each stroke is four LEDs in series and requires 9V 50mA to drive, and every digit have a maximum of 8 segments (7 segments for the number and one segment for the dots making up the colons.) There is only one boost converter on the board, and I must minimize the amount of constant current sinks I use.
The rest of the system runs on 5V straight off the phone charger, with
ATmega328P being the main microcontroller and
DS3231 keeping time.
- Will lighting up all 8 segments in a digit fry my
MC34063-based boost converter? If so, how do I prevent it from being fried?
- How to control the thing with minimum amount of power transistors, N-channel only?