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TPS61169: Some design question about TPS61169...

Peter Tseng
Genius 5555 points
Part Number: TPS61169
Other Parts Discussed in Thread: TPS61199

Dear Sirs,

My customer designed with TPS6169 and had some questions that need help.

  • Vin: 12V
  • BL : 80mA*4 / 28V
  • Cin and Cout use 10uF/50V MLCC 

They found 

1. there is audible noise cames from Cout

2. The input voltage will always change from 11.x V ~12.x V.

May I have your suggestion for it?

Thanks.

7043.sch.pdf

  • 0
    TI__Mastermind 19540 points

    Hi Peter,

    In the schematic the LED driver is TPS61199, is it what you are actually using now?

    And may I know how's the input voltage supplied with? I might suggest you check firstly whether the supply itself is stable or not.

    BR

    Patrick

  • 0 in reply to Patrick Yao
    Prodigy 10 points

    Hi Patrick,

    YES, it's using now.

    We are using the power supply to test TPS61199 with BL unit, the input 12V is very stable when not connect.

    Modify switch frequency and components (Diode, MOS, Inductor.), the issue was not gone.

  • 0 in reply to Rex Liao
    TI__Mastermind 19540 points

    Hi Rex,

    Do you have waveforms of output voltage and output current? And it'll be better if you have SW voltage waveform as well.

    Have you tired adding more output capacitors? Due to the DC derating of ceramic capacitor, 2*10uF might not be enough. Our datasheet recommends 3*33uF electrolytic capacitors.

    BR

    Patrick