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LED driver witch can be used 100kHz PWM dimming

Ryuji
Guru 20090 points
Other Parts Discussed in Thread: TPS92515, TPS92641, LM3409

Hello,

Are there any LED driver which can be used following specifications?
I couldn't found that the device witch can be used for 100kHz of PWM dimming frequency 100kHz.

<Specifications>
PWM dimming frequency : 100kHz
PWM Duty Range: 6~100%
Vin=18~27V
ILED=650mA
ILED accuracy: +/-2% at Ta=25C
Vout=10~16V


Best Regards,
Ryuji

  • 0
    TI__Mastermind 25500 points

    Hello Ryuji-san,

    If you need that kind of accuracy and such a high PWM frequency your best bet is the TPS92641 with shunt FET dimming. The TPS92515 and LM3409 might also work but they do not have as much accuracy and I'm not sure they could meet the 2% spec. 6% duty cycle will be hard as well as the pulse would only be 600ns long, but it may be possible. You will need to reduce parasitics by keeping the lead lengths to the LED load very short and you will likely need to take into account IC delays with such short pulses.

    Regards,

    Clint

  • 0 in reply to Clinton Jensen
    Guru 20090 points

    Hello Clint san,

    I appreciate your support.
    Could you please let me know the min/max value of Vref at Ta=25C?
    I appreciate it if you have any data.

    Best Regards,
    Ryuji

  • 0 in reply to Ryuji
    TI__Mastermind 25500 points

    Hello Ryuji-san,

    Do you mean the actual Vref of the device? Or do you mean the current regulation Vcs voltage?

    In any case Vcs has a total min/max offset of +/-600uV. That is an over temp spec, I do not have the room temp spec. Still, if you use a 200mV Vcs voltage that gives you +/-0.3% current accuracy worst case over temp.

    If you are actually interested in Vref it is about +/-0.8% on its 3V value over temp. I don't have a room temp spec for that either.

    So the accuracy is very good over temp and will only be better at room temp.

    Regards,

    Clint