I am making an 8x8x8 LED.
The actual cube is done, I'm just designing the driving circuit. The LEDs are arranged with a common cathode for each layer. I am going to use current source LED driving shift registers for the the anode columns, but not sure what to use for switching the layers.
I was originally going to use MOSFETs, but I had a few ULN2803As hanging around and wondered if I could use them. They will look much neater on my control board too. Also, MOSFETs have the gate capacitance to worry about when switching at higher frequencies. They are only rated at 500mA output per Darlington output, but the datasheet says they can be paralleled to get higher output. Now my question is....
A max of 64 LEDs on one layer multiplied by 20mA = 1.28A
Could I parallel 3 or 4 of the outputs of a ULN2803 without any worry? The cube obviously multiplexes each layer, so the average current will be 1/8th of 1.28A.
Any thoughts.
The actual cube is done, I'm just designing the driving circuit. The LEDs are arranged with a common cathode for each layer. I am going to use current source LED driving shift registers for the the anode columns, but not sure what to use for switching the layers.
I was originally going to use MOSFETs, but I had a few ULN2803As hanging around and wondered if I could use them. They will look much neater on my control board too. Also, MOSFETs have the gate capacitance to worry about when switching at higher frequencies. They are only rated at 500mA output per Darlington output, but the datasheet says they can be paralleled to get higher output. Now my question is....
A max of 64 LEDs on one layer multiplied by 20mA = 1.28A
Could I parallel 3 or 4 of the outputs of a ULN2803 without any worry? The cube obviously multiplexes each layer, so the average current will be 1/8th of 1.28A.
Any thoughts.