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TLC5947: Cascading TLC5947 and TLC 5944

Emma Darby
Prodigy 40 points
Part Number: TLC5947
Other Parts Discussed in Thread: TLC5944, , TLC5946

Hi there,

I have 24 different LEDs (5 red, 5 blue, 5 green, 4 white, 5 orange) that need between 8-20mA, depending on the LED colour. I would like to use the 24 channel, 30mA TLC5947 to power them and use PWM to change the current as it turns on different coloured LEDs. Each colour of LED is turned on at a different time (ie. all red on, then off, then all green on, then off, etc.). I also have 5 UV LEDs that need 55mA of current. I would like to use the 60mA TLC5944 to power those. I am using a raspberry pi 3 A+ to control the LEDs. I was wondering if:

(1) I can cascade the TLC5947 and the TLC5944 to achieve my design? Do they have the same control mechanism (ie. I can use the same cascading wiring configuration and the same code to control it)? If not, do you have another suggestion as to how I should power these?

(2) There is a readily available python library for me to code the two devices with my raspberry pi?

Thanks!

Emma

  • +1
    TI__Genius 12915 points

    Hi Emma,

    (1) No the data format is different between TLC5947 with TLC5944. TLC5947 have 24 outputs and needs 12 x 24 bits totally. Also it do not have DC function. Theoretically it could be work to cascade them, since they are all shift register interface. One device's data could be shifted through another's shift register, then latch them together, but we do not try before. I think you could use multiple higher current-capability device TLC5944 to control all LEDs.

    (2) Sorry that there is no python library for these devices.

  • 0 in reply to Hardy Wu
    Prodigy 40 points

    Thanks for the information Hardy! We decided to go with the 40mA TLC5946 instead. We are using two of them. Thanks for clarifying how the shift register interface could work.