How to light up 16 LED in turn by using NPN transistor and multiplexer?

Other Hardware LEDs and Multiplexing
1

I want to control 16 SMD LEDs and light up one after the other. It used a quad NPN transistors and one 16 channel multiplexer. However, the result showed that all LEDs lighted up at the same time and then closed in turn.
I tried to turn off all LEDs by applying logic 0 (EN=0), but it did not work.

2

You need to use a DEmux like a 74154 4 line to 16 line.
If you want to multiplex them... then use 8 lines and software.
There are other probably more elegant ways to do this but I do not know your application or which microcontroller you are using

Richard

4

Richard, thank you for your reply! I used Renesas Electronics RX210 series microcontroller. The 16 channel multiplexer is ADG706. I used one GPIO pin to control Enable, and four GPIO pin to control the four data input lines. The drain connect to GND. Is there any problem of the circuit? should I add the other resistance?

5

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