I am using this TI LED Driver IC to drive 9 LEDs

I want to calculate the Power Dissipation of the Resistor (20k 1% 0402) which I have connected to the IREF pin.

To calculate the power dissipation of that resistor, I am using ((V^2)/R) formula, where I am taking V in the range given in that datasheet as (1.204V to 1.254V) - Referring 6.5 section, page 5. Am I correct? And is the current through the 20k resistor sourced from the Vcc supply or from where?

Also I am trying to calculate the overall power dissipation and the Junction temperature of the IC.

Since TLC6C5712-Q1 does not have internal MOSFETs, how to calculate the power dissipation of the IC.

Can someone help me how this LED Driver IC internal architecture is different from LED Driver IC which has internal MOSFETs.


1 Answer 1


You are right in taking the reference voltage to calculate power dissipated. \$V^2/R\$

Take the worst case voltage (1.254 V).

Edit 2: How do i calculate power consumed by the driver:

Supply current times the input voltage will give the power consumption of the device.

enter image description here

Edit 3: Here are my observation:

  1. The TLC6C598 is a simple current sink. It can sink upto 50 mA (limited by rating of the transitors). The TLC6C5712 is a constant current driver

  2. The current limit in TLC6C598 set using external resistors (one per channel). The current limit in TLC6C5712 is set using single resistor (at IREF pin).

  3. TLC6C598 is for simple LED designs where as the TLC6C5712 is used for compensating LED color temperature and brightness.

  4. PWM support is there in both

enter image description here enter image description here

Edit 3:

The blue colored section, will be very tiny. you can ignore. enter image description here

  • \$\begingroup\$ Thank you for the answer, Could you also edit your answer to provide me clarity on the other questions. \$\endgroup\$
    – user220456
    Commented Mar 2, 2020 at 4:03
  • \$\begingroup\$ Can you please provide more details for my question \$\endgroup\$
    – user220456
    Commented Mar 3, 2020 at 2:45
  • 1
    \$\begingroup\$ Give me some time \$\endgroup\$
    – User323693
    Commented Mar 3, 2020 at 3:46
  • \$\begingroup\$ Thank you for the answer. Just a small query, when you say " Supply current times the input voltage" , when you say the input voltage, due to mean the input voltage of the IC, or the voltage which is present at the OUT pins in the IC? \$\endgroup\$
    – user220456
    Commented Mar 6, 2020 at 4:02
  • 1
    \$\begingroup\$ You are right. 3 V will be \$V_{out}/$. And the same equation as in edit 3 will be used to calculate total power dissipation. \$\endgroup\$
    – User323693
    Commented Mar 7, 2020 at 3:44

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