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LM3409: Run devices in parallel? Or a different device for 20A output, 30 khz pwm dimming

matthew
Prodigy 100 points
Part Number: LM3409
Other Parts Discussed in Thread: TPS92640

I have been using parallel fet dimming with the LM3409 to drive 1A - 3A LED's at 30 khz pwm dimming, I tested several LED drivers and the LM3409 was the best performer at this high PWM freq, so I'm hesitant to try something else. My current driver is designed for and works great at 3.5 A max. 

A new application is targeting one of the big chip LED's from luminous devices... these LED's are Vf= 5V at If = 20A. My first preference is to run 6 or more LM3409's in parallel. Has this been tested before? Any recommendations?

I would also consider any alternatives if there is a better low voltage, high current driver that can PWM at 30 khz.

  • 0
    TI__Mastermind 25500 points

    Hello Matthew,

    The LM3409 can do more than 3.5A, but it would be difficult to get to 20A. But yes, you can parallel them. You will need to be careful with layout and possible noise coupling, but they are basically current sources that can be paralleled.

    A better option might be to check out the TPS92640. It is synchronous and there are already reference designs, one for 20A in particular located at http://www.ti.com/tool/pmp8016 that might fit what you need. Thanks.

    Regards,

    Clint