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TPS54160: TPS54160

Kartik Jagtap
Intellectual 335 points
Part Number: TPS54160

Hi

I have an problem with  TPS54160, i am using 10-40V as input supply and getting 4.85V as output.

i am using reference circuit from data sheet (page no 31)  and to get 5v at the output selected R1=52k using this equation R1=R2 x ((vout-08v) / 0.8v).

 i use this output for LCD and micro controller ,problem is whenever i use this without LCD and micro controller connected  this works fine and gives 4.85v at output but when i connect it to the LCD and micro controller output voltage drop to 1.28V.

i  try to power LCD and micro controller using external 5V  power supply circuit works fine with (0.038A current).

i don't  understand what is the problem is problem with TPS54160 or LCD and micro controller.

below is my circuit i am using.

Thanks in advance

Kartik Jagtap

  • 0
    TI__Mastermind 23835 points
    Hi,

    Do you have the switch node waveform when you load the power supply? Maybe using a resistive load first and see how it behaves. Will it drop the voltage also?
    Have you try to add another 47uF capacitor at the output?
    Do you have the layout picture?

    Thanks
    -Arief
  • 0 in reply to Arief Hernadi
    Intellectual 335 points

    Hi Arief 

    Thanks for reply

    I am using 4.7uf aluminium electrolytic Capacitor,is there any problem because of this.

  • 0 in reply to Arief Hernadi
    Intellectual 335 points
    Need Help to resolve This issue.
  • 0 in reply to Kartik Jagtap
    TI__Genius 11085 points
    Hi Kartik,

    The schematic shows 47uF output capacitor. You are saying you have a 4.7uF electrolytic capacitor at the output. Please clarify which one is correct. 4.7uF is too small for this design, the loop maybe unstable. If 47uF is accurate, please try 47uF ceramic caps instead, as Arief suggested in the first reply.

    Please provide more information for us to help debug your issue. The TPS54160 is a 1.5A buck converter. It should handle 0.038A load without any issue.

    As Arief asked in the first reply, please try to connect the output of the TPS54160 to a resistive load and check the performance at different loading levels. Also provide PH node waveform when Vout dropped to 1.8V. If possible, please also provide Vout, Vin and PH waveforms during the transition when the output is connected to the LCD and uC.

    Regards,

    Yang