TPS54719: Schematic review: 3-6V input, 2.5V output ,7A

Hello Yuan,

Using WEBENCH to design your power solution is always a good start. You should define if this design is meeting the specifics of your application like output ripple, switching frequency, load regulation.

Will you be having a 7A output? Adding output capacitors will help your system to supply current to your load when the regulator cannot because of a fast increase in current but will slow down your system. These are consideration you should include.

Next step will be to follow carefully the Layout Guidelines, topic (10.1)

Do you have any questions on any of those comments?

Thank you very much!

Best Regards,

Dorian

Hi Dorian,

Thanks for the reply. I just have a little BOM difference with WEBENCH design I listed as below, this is because I have to selected some existing materials from company stock.  Do you think it will cause a big problem? 

R3034:  100K    REF: 86.6K

R3033:   15K     REF: 15.4K

R3035    7.5K    REF: 7.32K

R3036    33K     REF: 32.4K

L67         1uH     REF: 680nH 

 TPS54719RTER ‑ 3V-6V to 2.50V @ 7A

Also, TI have a ref design on website. and it is quite different to the WEBENCH. which one should I follow?

BTW, this design connect pin 7 and pin8 ,which is not in WEBENCH. Which one should I follow?

Dorian,

 Please don't be surprise . I'm following this question on behalf of my customer.  He complained the feedback is too slow. 

Hello Yuan,

Here I would follow WEBENCH design, shorting RT and COMP will definitely not help your design to have your target switching frequency and a good compensation loop, I would guess it is an error.

Using WEBENCH, you can click on the components there is on the design. A pop-up window will appear, you can click "choose alternate" to get other components with different values. If you want to look at the different possibilities you can have. 

For your resistors I think you just need to make sure their accuracy fit your specification. We usually recommend the use of +/-1% resistors.

For your inductor, you need to make that it's saturation current is not too low for your application. 

I advise you read topic 8.2.3.3 for the sizing of your output capacitors depending on your application requirement such as output voltage ripple and load transient response (max drop of your output voltage). Here we recommend the use of Low-ESR ceramic capacitors

Do you have any specific concern regarding your design? 

I think your schematic is fine.

Thank you very much!

Best Regards,

Dorian

Dorian,

About the compensation, is there a tool to calculate or just follow the Webench?