Dear TI team and others,
My question is regarding optimizing the current draw of the TLC5940, used as an LED driver in our application.
Our setup: In our product design, we are using the TLC5940 (QFN footprint) with R_IREF = 5 kOhm, thus I_OUT = 7.8 mA. All 16 outputs are connected to LEDs (with V_f = 2 Volts); the LEDs are switched/changed only approximately once every 200 ms. The setup is fully functional so far!
Now, with the above in mind, we are interested in optimizing the power consumption as much as we can.
We would appreciate some insight regarding these 3 points of interest:
#1) What would be the current draw of the TLC5940 specifically (i.e., excluding the LED power consumption) assuming we are switching only one LED on at any given time? The datasheet lists I_CC only for specific cases, so we would appreciate some information regarding this.
#2) What would be the recommended method to sleep/wake the TLC5940, if we plan to do so once every 100 ms, so as to keep the TLC5940 running for effectively a smaller duty cycle, and thus reduce the power consumption? Or is our current method the only way? Our current method is: Since the TLC5940 appears not to have any shutdown/sleep pin, we have instead added a loadswitch on the VCC line, so that we can use our microcontroller to switch off the power to the TLC5940 when our device is about to enter sleep mode, and switch the TLC5940 power on again when our device wakes up.
#3) What would be the total turn-on + initialization time for the TLC5940 upon being powered on? In other words, the time before it can first begin shifting in microcontroller serial data & switching the appropriate LED outputs?
Any information regarding the above is much appreciated!
Best regards,
Gamin Inganela
Olympia Labs
