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TLC59108: I want to connect the channels of each device

Kaji@PAN
Mastermind 7330 points
Part Number: TLC59108

Hi,

I am considering using the TLC59108 device.
The LED current is 300mA and requires 6 channels.
Since the LED voltage is about 3V, it will be about 6V per string in two series.
Since the LED current is 300mA, I am thinking of connecting the channels of each device to make a total of 300mA as shown below.
Is it possible to connect and use the channels of each device like this?

Best regards,

  • 0
    TI__Genius 12915 points

    Hi Kaji,

    I think your structure is OK and should be work. But usually when need large current, paralleling the channels in the same IC is more common used method. One IC controls 2 LEDs. For example, parallel channel 0, 1 & 2 for LED0 and channel 3, 4 & 5 for LED1 in first IC. and so as other ICs. It should be more easy to control the LED and layout the PCB.

  • 0 in reply to Hardy Wu
    Mastermind 7330 points

    Thank you for your reply.

    The reason I devised such a connection method is to reduce the frequency of I2C communication.
    When OUT0, OUT1 and OUT2 of one device are connected together, PWM0, PWM1 and PWM2 commands must be sent for dimming one LED.
    When OUT0 of each of the three devices is connected, we believe that dimming can be performed only by the PWM0 command at the all call address.
    The dimming cycle is 10ms. Then, the duty is changed from 0% to 100% in 20% steps.

    I am thinking about the above method, but are there any concerns to achieve this?

    Best regards,

  • 0 in reply to Kaji@PAN
    Mastermind 7330 points

    Since the deadline for device selection is approaching, it would be helpful if you could give me your opinion.
    Are there any concerns about connecting the OUTx pins of the three devices to create a circuit as described above?

    Best regards,

  • 0 in reply to Kaji@PAN
    Mastermind 7330 points

    I will ask additional questions.
    If OUTx is connected between different devices, does the constant current accuracy change? (Accuracy decreases, etc.)

    Best regards,

  • 0 in reply to Kaji@PAN
    Mastermind 7330 points

    Is it possible to give me an opinion?
    Can I proceed with the design by connecting the OUTx pins of the three devices?

    Best regards,

  • 0 in reply to Kaji@PAN
    TI__Genius 12915 points

    Hi Kaji,

    Are there any concerns about connecting the OUTx pins of the three devices to create a circuit as described above?
    I think there is no other concern about your structure. It should work

    OUTx is connected between different devices, does the constant current accuracy change? 
    The accuracy is determined by voltage on output pin. Make sure it is above saturation voltage in Figure 2 of datasheet.