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Original question:

TPIC6C596: Current capability

TPIC6C596: Strange power draw through adjacent LEDs

Khoi Ly10
Intellectual 620 points
Part Number: TPIC6C596

Dear TI,

I have two TPIC6C596 that are connected as follow:

The two drivers drive 16 IR Leds that are marked from 1 to 16.

I randomly chose LED number 9 for testing and I found that the current through the LED 9 slightly high whenever the driver turns on the LED number 8.

This behavior is the same for all LEDs. That is, I see an elevated current through LED number i whenever the LED number i - 1 turns fully on. The elevated current through LED number i causes that LED to turn ON dimly. Are there any potential fixes for this problem?

Thank you,

Khoi Ly

PS:

The below figure shows the setup of a cascaded LED driver pair. Overall, the system works fine, except the problem I mentioned above.

The below figure shows a typical LED, resistor setup. The problem remains the same even with a larger resistance value

  • 0
    TI__Mastermind 22745 points

    Hi Sir,

         So you only found the LED9 has a higher current than all other LEDs? Have you tried with other serial resistor? When you increase the resistor, whether the current will drop? I want to know the behavior of this channel.

    BR

    Sean