TPS53319: load transient response

Yuto Sakai

Part Number: TPS53319

Hi,

The customer is considering use under the following conditions.
VIN = 19 V, Vout = 5 V, Iout = 6 to 8 A, slew rate = 8 to 10 A / μs
When simulating with Webench, there is no problem when default rise time and fall time = 25 μA, but it was not able to normally control at slew rate 9 A / μs. Even if adding an output capacitor was not enough, can you say that this speed response can not follow?
Please let me know the conditions if you can.

TPA53319_rise and fall slew rate=25u.pdf

TPS53319_rise and fall slew rate=1u.pdf

TPS53319_rise and fall slew rate=1u_Cout=1000uF.pdf

Best Regards,
Yuto Sakai

over 6 years ago

0 JohnTucker over 6 years ago

TI__Guru**** 191445 points

Sakai-san,
That may be a limitation of the Webench model. I will get someone from that team to look into it.

0 Gerold Dhanabalan - Online Design Tools over 6 years ago in reply to JohnTucker

TI__Genius 14455 points

Hi Sakai-san,
Can you please share the WEBENCH design to my email id g-dhanabalan@ti.com

regards,
Gerold

0 Yuto Sakai over 6 years ago in reply to Gerold Dhanabalan - Online Design Tools

Mastermind 6100 points

Hi Gerold-san,

Thank you for your reply.
I shared the WEBENCH design with the e-mail address taught by you.
Please let me know if anything is missing.

Best Regards,
Yuto Sakai

0 Yuto Sakai over 6 years ago in reply to Yuto Sakai

Mastermind 6100 points

Hi Gerold-san,

Just checking to see if you received the E2E post and your thought on the matter.
I am still expecting your response regarding TPS53319.

Best Regards,
Yuto Sakai

0 Gerold Dhanabalan - Online Design Tools over 6 years ago in reply to Yuto Sakai

TI__Genius 14455 points

Hi Yuto-san,
Sorry for the delay. We are looking into this.
Regards,
Gerold

0 Yuto Sakai over 6 years ago in reply to Gerold Dhanabalan - Online Design Tools

Mastermind 6100 points

Hi Gerold-san,

Because the condition of the slew rate of the customer is severe,
I want a guideline on how much output capacitor is necessary to suppress the load regulation to the target.
I'd like information on how much capacitance of output capacitor is needed for regulation.
It will be helpful if I can respond at this slew rate.

Best Regards,
Yuto Sakai

0 JohnTucker over 6 years ago in reply to Yuto Sakai

TI__Guru**** 191445 points

Sakai-san,

While the Webench team is working this, you could use the Pspice transient model to simulate your circuit:
www.ti.com/.../slum313

0 Harish K R over 6 years ago

TI__Intellectual 2320 points

Hi Sakai-san,

Thanks a lot for your patience. We want few clarification on the shared design.

The design which has been shared has load transient transiting from 10A to 1A in 1us resulting in slew rate of 9A/us. We are still looking into the issue. In the mean while, you could use the Pspice transient model to simulate your circuit:

www.ti.com/.../slum313

But as per your initial query, Iout mentioned is 6A to 8A. We simulated design for Vin=19V, Vout=5V, Iout=8-6-8A with slew rate of 2A/us and is working fine.

Could you please confirm on the Iout range ?

Best Regards,

Harish

0 Praveen Badiger over 6 years ago in reply to Harish K R

TI__Expert 8365 points

Hi Sakai-san,

This issue was due to WEBENCH simulation parameters. We have fixed this issue.Vout profile looks proper for Iout transiting from 10A to 1A for a slew rate=9A/us.You will able to see these changes in ti.com by next week.

Below is the snapshot of simulation results.

Thanks & Regards,

Praveen B

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TPS53319: load transient response