TPS40057: Inductance scream issue of technology support

Zhang Liang

Expert 2075 points

Part Number: TPS40057

Hi,

We test the TPS40057 for our new design and the Inductance scream when the power on( the light also has the inductance scream), when we load the increase circuit load, the scream is more intense,

Pleaes kindly review the below circuit and advies how to solve this issue? thanks.

The parameter as below: Input voltage: 24VDC, output voltage: 4.3VDC, max. current: 20A, Inductance: 4.7uH, Fsw=300KHz;

Schemtic diagram as below:

over 1 year ago

0 EricLee over 1 year ago

TI__Mastermind 46141 points

Hello Zhang

Would you please download the Calculator at https://www.ti.com/lit/zip/sluc263 , input your electrical specifications & components selections, and then send the excel file to me?

- Eric Lee

0 Zhang Liang over 1 year ago in reply to EricLee

Expert 2075 points

Hi Eric,

Please kindly review below excel and inform me if there are any other request, thanks.

TPS40K TPS5 Type III Loop Stability kVenable 的副本.xlsm

0 EricLee over 1 year ago in reply to Zhang Liang

TI__Mastermind 46141 points

Hello Zhang

You should know the ESR of the output capacitors. I input 20mOhm ESR as an example.

Also, FCO should be less than 1/10 x Fsw. I input 20kHz as an example.

Fz_1 and Fz_2 should be located at the LC resonance frequency. Fp_1 should be located at he ESR zero. Please refer https://training.ti.com/buck-converter-loop-compensation-overview for more detail information.

- Eric Lee

0 Zhang Liang over 1 year ago in reply to EricLee

Expert 2075 points

Hi, Eric,

We have changed the device like below, but there are no any improve for the inductance howlround, so please kindly advise if there are any other suggestion, thanks.

0 EricLee over 1 year ago in reply to Zhang Liang

TI__Mastermind 46141 points

Hello Zhang

If it is not caused by the instability, then I guess the system is restarting at audible frequency now. Can you share waveforms which you have?

- Eric Lee

0 Zhang Liang over 1 year ago in reply to EricLee

Expert 2075 points

Hi, Eric,

Yes, we can hear the inductance howlround when this is light load, and it is more and more loudly when we increase the load, so we consider the frequency is in the audible frequency, so your mean we will grab waveform of the SW pin?

+1 EricLee over 1 year ago in reply to Zhang Liang

TI__Mastermind 46141 points

Hello Zhang

Please share BP10, SS, Inductor current, COMP waveforms at different output current conditions for more investigation.

- Eric Lee

0 EricLee over 1 year ago in reply to EricLee

TI__Mastermind 46141 points

Hello
I am closing this thread since I have not heard from you for sometime.
If you are still trying to resolve the issue, please feel free to open a new thread or reopen this thread. Thanks
- Eric Lee (Applications Engineering)

Power management

Power management forum

TPS40057: Inductance scream issue of technology support