Hi i want to use a pic microcontroller to control an array of 50 leds. I'm using two ULN2803 ICs to control the anode and cathode of the leds but
i'm having problems with my schematic because ULN2803 is a NPN transistor array and i can only sink the voltage and not supply it. Is there any PNP array
IC?
This is the schematic for one led but it doesn't work. The IC1 can't sink the voltage when i apply voltage to the input.
Hi i want to use a pic microcontroller to control an array of 50 leds. I'm using two ULN2803 ICs to control the anode and cathode of the leds but
i'm having problems with my schematic because ULN2803 is a NPN transistor array and i can only sink the voltage and not supply it. Is there any PNP array
IC?
In your design the open collector goes straight to +5V and the emitters are grounded. So in reality you will have a burned 2804 gate. Above all you need a pull up to 5V on O1 and not 5V straight. Actually as andre_teprom pointed out, you could leave IC2 unconnected, put a led in series with the pull up and you are ready.
Alexandros
I need to control each one of the 50 leds the way i want. I found some PNP driver ICs such as UDN2981A and TD62783 but i need more equivalent in case it's hard to find these.