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TPS65233-1: Audible noise

Part Number: TPS65233-1
Other Parts Discussed in Thread: TPS65235-1, TPS65235

HI SIr 

We are using TPS65233-1 have audible noise 

1. Do you have any experience of this issue ? how to solve 

2. I saw TPS65235-1 have avoid audible function ,may i know the history??

Thanks 

  • Hi, Kai-san

    The audible noise is generated by the BOOST output capacitor(MLCC) who has piezoelectric charateristic.

    At light load, when the BOOST ripple frequency is within 20 ~ 20kHz and ripple amplitude is big enough, the sound will be heard.

      

    1. For TPS65233-1, the work around is adding about 15mA dummy loading at VLNB output, which will make the BOOST frequency out of audio frequency range. 

    2. For TPS65235, it also has audible noise at light load, the principle is same with TPS652333/-1 parts, so TI develops the TPS65235-1 to eliminate the audible noise.