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TPSM828303: there is a whistling sound when I use TPSM828303

peng tiansheng
Prodigy 20 points
Part Number: TPSM828303

Tool/software:

I use TPSM828303 on PCB and this power chip  generate a whistling sound，I would like to ask about the possible reasons for this phenomenon. SCH and PCB as follow：

  • 0
    TI__Mastermind 22490 points

    Hello Peng,

    thanks for reaching out in E2E.

    When the MODE pin of the TPSM828303 is set to 0V then the device is operating in PSM/PWM operation. That means the device is automatically transitioning to PSM (Powe Save Mode) for light load conditions and maintains higher efficiency in this condition. PSM is also known as discontinuous conduction mode, which means the switching frequency is getting reduced and only occasional switch events maintain the output voltage (depending on the load). This also means the switching frequency can become as low as audible frequencies (kHz range). Mechanical deformation of the PCB or of the capacitors can occur in this frequency range and lead to audible noise.

    You could apply a higher load (dummy load) to increase the switching frequency outside the audible range or you could enable Forced-PWM by setting the MODE pin to high. Both options would reduce the efficiency. You could also try to optimize the PCB design and the used capacitors for avoiding mechanical vibration, as described in this application note: "How to Reduce Acoustic Noise of MLCCs in Power Applications".

    Best regards,

    Andreas.