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Original question:

TPS54531: Request for Support – Noise and Short Issue in TPS54531 Circuit and Inductor also Heating

TPS54531: Request for Schematic Update – Output Change to 10V / 4.5A

mahesh p
Prodigy 40 points

Part Number: TPS54531

Dear Sir,

 

As per your previous suggestions, the noise and heating have reduced — the circuit is now working well.

I now need to change the output voltage to 10V / 4.5A, with the input remaining 12V–27V.
Could you please check the attached schematic and let me know what component values I need to change for this update?

Thank you for your support.

Best regards,
MaheshTPS54531.pdf 

  • 0
    TI__Genius 14090 points

    Hi Mahesh,

    We will check and get back on this.

    Regards,

    Haseen.

  • 0
    TI__Expert 4860 points

    Hi Mahesh

    1. Please change the inductor to ~10uH to make sure that the ripple is below 30% even at 27V. If the inductor is kept same, the ripple may go as high as 40%. Since the input looks like a PV panel, I am assuming that the voltage will be mostly sitting around 20-22V. (VMPP)
    2. Place a decoupling capacitor of 100nF, X7R, 0805 on the input pin very close to the IC. You may replace 1Nos. 4.7uF capacitor with this one.

    Rest of the schematic looks fine. Request you to close both the threads once your query is resolved. 

    Thanks!

    Regards

    Nikhil 

  • 0 in reply to Nikhil S Bhardwaj
    Prodigy 40 points

    Dear Nikhil,

    Thank you for your valuable suggestions. I will update the inductor to ~10µH and add the 100nF decoupling capacitor as recommended.

    I have a couple of final clarifications:

    • My required output voltage is 10V. The schematic I shared earlier is for 12V output. Do I need to change the feedback resistor  to get 10V output, or will it work without any change? Please confirm.

    • My input voltage will remain 12–27V, and I need an output of 10V / 3.5A. Which resistor controls the output current in this circuit? Also, can I keep the inductor value as 10µH for 3.5A output?

    I hope this is my last query, and I will close the thread after your confirmation.

    Thank you for your support.

    Best regards,
    Mahesh

  • +1 in reply to mahesh p
    TI__Expert 4860 points

    Hi Mahesh

    My required output voltage is 10V. The schematic I shared earlier is for 12V output. Do I need to change the feedback resistor to get 10V output, or will it work without any change? Please confirm.

    • Yes, you will have to change the VSENSE resistors accordingly to match 0.8V at 10V the way you did it for 12V.

    My input voltage will remain 12–27V, and I need an output of 10V / 3.5A. Which resistor controls the output current in this circuit? Also, can I keep the inductor value as 10µH for 3.5A output?

    • The output current is a function of the load and not controlled by any resistor as such in the circuit. . Yes, you can use a 10uH inductor for 3.5A too. Just make sure the current ratings are okay as mentioned earlier. 

    Thanks

    Regards

    Nikhil