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TLC5944: Request for Information on TLC5944 LED Driver Usage

emily cad
Prodigy 20 points
Part Number: TLC5944
Other Parts Discussed in Thread: LP5864, TUSB3410

Hello,

I have a specific requirement to drive a LED array consisting of 60 LEDs, with 30 IR LEDs and 30 RED LEDs. After researching the capabilities of the TLC5944, I believe that using four TLC5944 drivers would fulfill my requirements.

My main objective is to be able to individually turn on and off the LEDs. I intend to sequentially control each LED, ensuring that only one LED is on at a time. Additionally, I need the ability to adjust the brightness of each LED independently. I am seeking guidance on whether this driver is capable of achieving these functionalities.

If it is indeed possible to control the on/off state and brightness of the LEDs using the TLC5944, I would appreciate some information on how to accomplish this. For instance, do I need to send data to the grayscale shift register? Could you provide an example of how I could turn on LED0 for driver0? Would I simply send the value 0000 0001 to the driver?

Furthermore, during my research, I discovered that TI provides a TLC594x Family evaluation software. I am interested in utilizing this software with our self-developed board that incorporates the TLC5944 along with an STM32 MCU. Is it feasible to use the TLC594x Family evaluation software with the TLC5944 on a custom board?

I attempted to launch the software, but encountered issues with its functionality. Is there an alternative method or any additional resources available that would enable access to this software?

Thank you very much for your time and assistance.

  • 0
    TI__Expert 6440 points

    Hi,

    Nice to hear you!

    Actually, if you want to control 60 LEDs independently, you may need 4 TLC5944 or 2 TLC5944 with 2 external scan FET and controller, so I believe it is not the most suitable device for your applications.

    So, I'd like recommend you LP5864, which integrated 18 current sink and 4 scan FET, only 1 device can drive up to 4 * 18 = 72 LEDs, and it is controlled by I2C/SPI interface, each LED dots could be controlled by 8-bit/16-bit PWM dimming and 8-bits analog dimming. I believe this device is more easily to be used than TLC5944.

    And let's go back to your questions for TLC5944, so need to update all GS shift register (16*12 = 192 bits) with LAT signal so the device can generate the output you want. Each channels has independent 12-bits PWM control which is configured by GS data.

    The EVM GUI software communicates with the Driver board through a TUSB3410. The TUSB3410 communicates with the DSP board with an RS-232 protocol. So you cannot use the software to control your STM32 MCU.

    If you want to use the software to evaluate the TLC5944 in your custom board, you can request an EVM from our website ti.com, and then use cables to connect the control signal in the EVM to your custom board.

    Thanks!

    Ives Li

  • 0 in reply to Ives Li
    Prodigy 20 points

    Hello, 

    thank you for your support ! I will definitely take a look at the LP5864. Can you please tell me a little bit about how it works ? How does data transmission work, for example, how do you light one of the 60 connected LEDs? Is there any software for the LP5864? 

    BR

  • 0 in reply to emily cad
    TI__Expert 6440 points

    Hi,

    Sure, LP5864 integrate 18 current sink and 4 scan FET, with time multiple topology, it can drive up to 18*4 = 72 LEDs.

    And for LP586x family, we have GUI and EVM to evaluate it, please find more information on the ti.com.

    LP5864 data sheet, product information and support | TI.com

    Thanks!

  • 0 in reply to Ives Li
    Prodigy 20 points

    Hello, 

    thank you for your recommendation, I will use the LP5864 for my project.

    I have read the data sheet and I have two questions : 

    How to select power supplies VLED and VCC? In the data sheet, TI provide  a range for those of 2.5V to 5.5V, but is there any way to calculate the theoretically minimal/maximum value ? Are there any limits about the ripple current, for example? 

    Could you provide more relevant resources for LP5864 ?

    Thanks for your support ! 

  • +1 in reply to emily cad
    TI__Expert 6440 points

    Hi,

    For VCC:

    If you want to generate 50mA current for each channel, please select VCC from 3.3 - 5.5V

    For VLED,

    The minimum value for VLED could be calculated by below:

    VLED > Vf + Vsat + Vl

    Vf: Forward voltage of LED on the setting current condition

    Vsat: Voltage of current sink to generate the setting current.

    Vl: Line voltage drop.

    Thanks!