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TLC59116F: 16-channel LED driver that can output 20mA per channel.

Atsushi Takahashi
Expert 1415 points
Part Number: TLC59116F
Other Parts Discussed in Thread: TLC59116

Tool/software:

Hi Team,

I'm looking for a 16-channel LED driver that can output 20mA per channel.
I did the following calculations for TLC59116F and I think it will work.

Conditions;
Vcc = 5.5V, Vout = 17V, Iout = 20mA per ch

Iout^2 x Ron x Nch
= 20mA^2 x 3.75Ω x 16ch
= 24mW

Icc x Vcc
= 13mA x 5.5V
= 71.5mW

Pd_total
= 24mW + 71.5mW
= 95.5mW

θja x Pd_total
= 78℃/W x 95.5mW =7.449℃

Ta_max + θja x Pd_total
= 85℃ + 7.449℃
= 92.449℃ < 150℃(Tj_max)

1) Is my understanding above correct?

2) The Ta of this product is 85℃. In addition to the above conditions, are there any products that support up to 105℃?

Best Regards,

  • 0
    TI__Mastermind 20515 points

    Hi Atsushi,

    I see it, you want to calculate the thermal rising for the IC. I think it's wrong.

    I'd like to ask a few questions below, please help to confirm.

    1. I noticed that you said your requirement is that you need a 16-channel LED driver and with 20mA per channel. But I am wondering that if you need higher than 6V output. Is your LED load LED strip, not a single LED? Am I right?

    2. Can you please tell me why you choose TLC59116F but not TLC59116?

    3. Please tell me the voltage dropped on the output, then I can help to calculate the thermal for you.

    BR, Jared

  • 0 in reply to Jared Zhou
    Expert 1415 points

    Hi Jared-san,

    Thank you for your reply.

    I'll answer your questions.

    1. Sorry. The information above was incorrect. One LED is connected per channel. It is a single LED load.
    2. The TLC59116 generates a lot of heat from the IC because it is driven by a constant current.The TLC59116F generates less heat because it is driven by a constant voltage using FET.I chose the TLC59116F for that reason.
    3. One LED is connected per channel. The voltage of the OUTx-pin is about 3V and Vf is about 3V.

    The customer's usage conditions are as follows.

    Vcc = 5V, Out = 3V per ch, Vf = 3V, Iout = 20mA per ch(Total 320mA)

  • 0 in reply to Atsushi Takahashi
    TI__Mastermind 20515 points

    Hi Atsushi,

    Thanks for your reply, I will get back to you later.

    BR, Jared

  • +1 in reply to Jared Zhou
    TI__Mastermind 20515 points

    Hi Atsushi-san,

    Thanks for your patience!

    Ok, I see it. The reason why you want to use TLC59116F is because the LED load per channel is only 1 LED, if using TLC59116 directly, the thermal will be very tough. Thanks for your explanation!

    As my understanding, if you want to get the output current 20mA per channel under 17V VLED power supply, the resistor will be about 685Ω ? Am I correct?

    Please refer my below comments for the thermal calculation:

    1. The power consumption for the output current sink: Iout * Vout * channel number

    20mA * 0.3V * 16 = 0.096W

    2. The power consumption for the IC: Icc * Vcc

    13mA * 5.5V = 0.0715W

    3. The thermal calculation:

    (0.096+0.0715) * 78 = 13.065 C

    Therefore, I think it can work under 85C temp. Please let me know if there is any question.

    BR, Jared

  • 0 in reply to Jared Zhou
    Expert 1415 points

    Hi Jared-san,

    Thank you for your reply.

    >As my understanding, if you want to get the output current 20mA per channel under 17V VLED power supply, the resistor will be about 685Ω ? Am I correct?
    I'm sorry. the information is wrong. The correct conditions are below.
    Vcc = 5V, Out = 3V per ch, Vf = 3V, Iout = 20mA per ch(Total 320mA)

    > 20mA * 0.3V * 16 = 0.096W
    Is 0.3V(Vout) correct?
    They are using Voltage of OUTx-pin = 3V per channel.

  • 0 in reply to Atsushi Takahashi
    TI__Mastermind 20515 points

    Hi Atsushi-san,

    Actually, the voltage dropped on the VOUT is decided by your LED power supply, forward voltage of LED and the resistor connect serial in the channel.

    Do you mean the power supply for the LED is 3V? If yes, how can you drive the LED that the forward voltage is 3V. Can you please help to clarify for me?

    Btw, the 0.3V is calculated by the following conditions:

    VLED=17V, Iout=20mA, Vf=3V

    BR, Jared

  • 0 in reply to Jared Zhou
    TI__Mastermind 20515 points

    Hi Atsushi-san,

    Is there any problem here? If not, I will close this topic. Thanks!

    BR, Jared

  • 0 in reply to Jared Zhou
    Expert 1415 points

    Hi Jared-san,

    I'm sorry for the late reply.

    Your kindly supports ware very helpful.

    I'll close this topic.