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LM3445-230VFLBK: Audible noise with triac dimmers

Devansh Sharma
Prodigy 10 points

Part Number: LM3445-230VFLBK

Hello,

I have purchased LM3445 evaluation board and it is able to deliver dimming of LEDs with triac dimmers. However I am facing a major issue of high audible noise at 0-70% dimming range. Please let me know if it is normal to generate noise for this evaluation board or kindly suggest ways to eliminate it.

The part number is - https://www.mouser.in/ProductDetail/926-M3445230VFLBKNPB

Regards

Devansh

  • 0
    TI__Mastermind 28655 points
    Hello Devansh,

    This is common. The triac dimmer has a high dv/dt on its rising edge. This can cause the EMI filter components to emit audible noise. It can be the X-capacitors and the EMI filter inductors. Some components are worse than others in this regard. If this will be potted in an enclosure the issue may just go away. Otherwise it's about trying different components and possibly different mounting on the PCB.

    Regards,