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TLC59116: About the maximum output power of each channel of TLC59116

SHENG YANG
Expert 1320 points
Part Number: TLC59116

HI ALL！

In PDF document, the maximum output current of each channel of TLC59116 is 120mA and the maximum output voltage is 17V. I want to know what is the maximum output power of each channel of TLC59116? This parameter was not found in the PDF. Thank you very much.

  • 0
    TI__Genius 12915 points

    Hi jin,

    Outputs of TLC59116 are only current sink, that drive current from VLED power supply and cannot generate power. So I think there is no conception of output power.

  • 0 in reply to Hardy Wu
    Expert 1320 points

    Thank you for your answer ！Hardy Wu！

    As shown in the figure below.The formula is used to calculate the power.Tj(max)=150，How much should TA be taken as the ambient temperature for IC operation? How do I usually get it.If you use a 32 pin chip, =34.3? Please tell me the correct calculation method of the following formula. thank you.

  • 0 in reply to SHENG YANG
    Expert 1320 points

    The content above is from the PDF of TLC59116

  • 0 in reply to SHENG YANG
    TI__Genius 12915 points

    Hi Chaoyang,

    Take the example in section 12.3 that setting all 16 channels output current at 50mA with 1V output voltage. Whole power dissipation is 0.8W. The increasing temperature on IC from room temp is 34.3 x 0.8 =  27.4C. If you need more precise results you could also calculate power dissipation on VCC and IREF, but they should be small. RHB package have thermal pad beneath IC so the thermal performance is good.

  • 0 in reply to Hardy Wu
    Expert 1320 points

    HI!Hardy Wu!

    The IC output voltage is not necessarily 1V, but should be the input power voltage minus the LED voltage drop, which may be much higher than 1V.If the maximum current is 120mA and the voltage is the input voltage minus the diode voltage drop, I can calculate the power P from the current and voltage.My question is what is the maximum upper limit of the output power p?There must be a reference value of power that tells me not to exceed this value.Note: the maximum current per channel of the chip is 120mA.

  • 0
    Expert 1320 points

    HI!ALL!

    Which engineer can help me to answer this question. This is very helpful to my work. Thank you very much.

  • 0 in reply to SHENG YANG
    TI__Genius 12915 points

    Hi Chaoyang,

    Sorry that I missed the notification before. I still not recommend the words 'output power p' to describe the outputs of TLC59116, because they are all current sinks that can only drive current. The voltage on output pins are determined by VLED minus Vf of LED as you said.

    The max rating of OUT pins is 20V. Every channel can support 120mA x 20V. But in this situation thermal would be generated large and beyond internal thermal shut down protection, which is around 175C. So that we recommend you design the voltage drop on output pin properly. Usually do not exceed 2V.

    If your power line of VLED is to high and the LED number you need to cascade on one channel is small, I recommend you also cascade one series resistor into the channel to separate the thermal and decrease the voltage on output pins.

  • 0 in reply to Hardy Wu
    Expert 1320 points

    Thank you very much for your reply！Hardy Wu！

    The answer I got is that the maximum current is 120mA, and the maximum port voltage should not be greater than 2V.My current design is that the maximum current is 120mA, and the port voltage is 1.3V ~ 1.5V, which will not exceed 2V.On this basis, do a good job in the chip heat dissipation is OK?

  • 0 in reply to SHENG YANG
    TI__Genius 12915 points

    Hi Chaoyang,

    Based on calculation, your design may lead to 100C temperature increasing on IC. It can work normally but I am not sure if this temperature is acceptable in your whole system. I suggest you also could cascade 0ohm resistor to every channel in case there need to separate some heat. Also putting large copper area below thermal pad could help dissipate heat.

  • 0 in reply to Hardy Wu
    Expert 1320 points

    Thank you very much for your reply！Hardy Wu！