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About troubleshooting of TPS65235EVM

Satoshi
Guru 19645 points
Other Parts Discussed in Thread: TPS65235-1

Customer is evaluating TPS65235EVM, but below problem is occured.

Please let me know about proposed measures for three points below.

-----------------------------------------------------------------------

①Sound noise is occuring, customer spec is below.

　・12Vin→11V～15V / 600mA_max

　・Sound noise is only 11Vout, 15Vout is no problem.

　・When 11Vout；

　　No load→No sound noise,

　　Light load→Occure sound noise. If increase current, sound is high key.

　　More than 400mA→No sound noise

②Therefore EXTM pin input 44kHz(3.3V), sometimes clock output is 22kHz.

　Is there way to certainly 44kHz output?

③otherwise, if below pin unused, are these pin left Open OK?

　#14：DOUT, #15：DIN, #19：GDR

-----------------------------------------------------------------------

Best regards,

Satoshi

  • 0
    TI__Expert 4705 points

    Hi, Satoshi,

    Please check my feedback , any unclear, please let me know.

    1. Yes, with 12Vin to 11V output , at light load, it will have the chance to hear the noise. please try to set the part work at force PWM mode, it will be better.

    Also, even work at force PWM mode, there is still have the chance to hear it. so we already have the spin project TPS65235-1,which can remove the noise when working at force PWM mode. so far, we have got the TPS65235-1 samples for testing. the plan to RTM is about December.

    2. could you please provide detail operation at customer side? like what the sequece for seting the regsister and tone input? any operation did they do after having the 44KHz tone input? did they switching them? or when they fix the 44Khz tone input, sometimes it has 22KHz tone output, sometimes it has 44KHz tone output?

    3.yes, they can be floating.

    BR
    Junjie