# Independent LED control in a matrix

My task is to control 64 LEDs with a 16-output drive. The control of each LED must be individual, that is, the activation of one LED must not interfere in the functionality of another.

I'm using an MBI5039 drive that sends a negative signal to activate the LED.

I thought of an 8x8 matrix where I can control rows and columns. For example, to turn on LED D0, I must activate the outputs OUT_0 and OUT_8.

When I want to turn on LEDs D0 and D1 at the same time, I must activate the outputs OUT_0, OUT_8 and OUT_9.

Now when I want to turn on LEDs D0, D1 and D10 I must activate the outputs OUT_0, OUT_1, OUT_8 and OUT_9. However, at that moment something happens that I don't want: LED D9 is also turned on.

I would like to know if there is any way to make the independent control of each led using matrix. I would not like to have to use a multiplexed circuit.

Note: I know the need for passive components (resistors) for the correct operation of the MOSFETs. The image circuit serves only for a logical explanation.

• Your circuit IS multiplexed! You can only control a given row at a time. If you wish to avoid multiplexing, then you need to use different circuitry - there are led driver ics for this purpose. – Kartman Feb 4 at 20:42
• You might want to check out WS2811 LED drivers to get more continuous power to your LEDs. You can also achieve dimming that way. – K H Feb 5 at 1:10
• In your own words, what does multiplexing mean? – user253751 Feb 5 at 5:12

As @Kartman says you have limited control over an individual LED.

The usual way around this is to rapidly cycle through the rows at >50 times per second and only illuminate the LEDs in that row you wish to be active. Any particular LED will only be on for 1/8th of the time as there are 8 rows. The current needs to accommodate this to meet the brightness requirements.

Persistence of vision will make it seem that all the LEDs that are turned on seem to be illuminated at once.

Most displays that have multiple LEDs use this or a similar multiplexing technique, whether it is an alarm clock with just a few digits each with 7 segments or an OLED TV with millions of LEDs.

Cross activation of elements other than the desired ones is a facto of life with multiplexed displays but luckily LEDs have built-in diodes to avoid it being an issue. If you used other types of lamp such as incandescent then you would need to include a diode in series with each.

Multiplexed display – the basics

• LEDs do not have built-in diodes, they are diodes. LED means "light-emitting diode." – the busybee Feb 5 at 12:45
• @thebusybee - precisely, they are intrinsic to their construction. – Kevin White Feb 5 at 17:03