TPS63070: Any consequence for using smaller than recommended R1/R2 and R3 resistors

Al B

Part Number: TPS63070

From my customer...

I am wondering if there is any consequence for using small than recommended R1/R2 and R3 resistors. (There will be more DC current wasted of course)

Would there be any stability issue say if we use R1=53k and R2=10k R3=22k?

over 6 years ago

0 Minqiu Xie over 6 years ago

TI__Mastermind 21565 points

Hi AL B:

May I know why customer will prefer a smaller resistance, as it will take a lot of power loss. It will decrease the efficiency especially for light load or no load.

We have an application note and a calculation tool for VSEL function.

http://www.ti.com/lit/an/slvae62/slvae62.pdf

http://www.ti.com/product/TPS63070/toolssoftware

0 Minqiu Xie over 6 years ago in reply to Minqiu Xie

TI__Mastermind 21565 points

Hi AL B:

I have checked with team. It seems not stable issue for small resistance. And we have a application note may give the details analysis: http://www.ti.com/lit/an/slyt469/slyt469.pdf

0 Al B over 6 years ago in reply to Minqiu Xie

TI__Intellectual 2990 points

Minqiu, from the customer...

Many thanks for your fast reply. Yes, I saw the app note before.

The reason why we use smaller resistance value is that we use a current DAC for dynamic output voltage adjustment. It just so happen that smaller resistance can give us full range.

As long as there is no stability issue, we can take more power loss.

Minqiu, can you clarify. When you say, "it seems not stable issue for small resistance" do you mean no problems?

0 Minqiu Xie over 6 years ago in reply to Al B

TI__Mastermind 21565 points

Hi AL B:

There is no issue in our lab and we think the impact to the loop is very small.

But we couldn't guarantee for every part and circuit, as it's beyond our validation requirements.

Thanks for your understanding.

Power management

Power management forum

TPS63070: Any consequence for using smaller than recommended R1/R2 and R3 resistors