• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 65 subscribers
  • Views 196 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

TLC59731: Maximum Vf for given VCC?

TLC59731: Current Capabilities

Wesley Mandel
Prodigy 30 points
Part Number: TLC59731

Tool/software:

Hello,

I see that this IC's datasheet recommends a maximum Dx channel current of 25mA, but does state that it maxes out at 50mA if Iset is connected to Gnd.

Is connected Iset to Gnd a viable design option?

I have a design where I would like to drive two LEDs in parallel with an average of 75mA through each if I can tune some ballast resistors. It seems that I could potentially achieve this through maxing out this IC's capability.

Is that a sustainable option, or will this significantly shorten this IC's lifespan?

To add context, these LEDs will not be permanently on, but flashed in a pattern potentially up to a 50% duty cycle.

Thank You,

Wesley Mandel

  • 0
    TI__Mastermind 28740 points

    Hi Wesley,

    Our expert will give you reply later.

  • 0
    TI__Genius 17465 points

    Hi Wesley,

    I don't think TLC59731 can support 75mA, please refer the datasheet to use it under 50mA conditions.

    Can you please tell me who is the customer and what is the detail requirements from customers, then I think help to find a better solution for you.

    BR, Jared

  • 0 in reply to Jared Zhou
    Prodigy 30 points

    Hey Jared,

    Thank you for replying to this. I apologize for some lack of context. From the datasheet, I need to connect each Dx together to get a 75mA current output as shown in Figure 12 of the datasheet:

    That 75mA current is for the device running at the recommended output current of 25mA per Dx channel. I am working on driving two LEDs each with 75mA of current, but this device will not handle them in series. Parallel seems to be an option if I max out the Dx output capabilities to each sink 50mA of current. This will allow me to use the circuit in Figure 12 for a total of 150mA of current through parallel LEDs.

    My inquiry is if it is possible and sustainable for the device to use the 50mA output per Dx channel and arrange them in the circuit shown in Figure 12. I get that it is theoretically possible, but want to know if doing so will be detrimental to its lifespan.

    Would using it only to flash the LEDs reduce strain on the device?

    As for the customer, it is the company I work for. If you would like more clarifying information on the part search I would prefer to discuss that over email or another private form of communication. 

    Thank You,

    Wesley Mandel

  • +1 in reply to Wesley Mandel
    TI__Genius 17465 points

    Hi Wesley,

    Thanks for your detail feedback!

    Based on my experience, I think it would be no problem to set the output current to 50mA and connect as Figure12 shows to realize 150mA.

    For the detail project information, application and end customer. Please help to send to my email (jared-zhou@ti.com). Thanks!

    BR, Jared