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TPS63070: How is Minimum Rload Required during Start-Up Determined?

Austin Allen

Intellectual 2555 points

Part Number: TPS63070

Hello,

I have a contact using the TPS63070 in a Buck-Boost configuration and there is a Rload_crit value that is described as the "Minimum Rload Required during Start-Up". This value appears to vary quite a bit with adjusted parameters and we are wondering how the value for this parameter is determined?

I consulted the datasheet but all I could find about minimum start-up load was:

Thank you,

Austin Allen

over 4 years ago

0 Minqiu Xie over 4 years ago

TI__Mastermind 21565 points

Hi Austin:

For the startup, the converter decreases the current limit.

In other way, what's the load for your design during the startup? And the Vin, Vout condition.

0 Austin Allen over 4 years ago in reply to Minqiu Xie

TI__Intellectual 2555 points

Hi Minqiu,

How does it decide the output current limit? I notice that the Rload_crit is either 15Ohms (if Vout < Vinmin) or 40.9Ohms (if Vout >Vinmin)

I am not sure about the load at startup but will check!

Best,

Austin Allen

0 Minqiu Xie over 4 years ago in reply to Austin Allen

TI__Mastermind 21565 points

Hi Austin:

What's the Vin and Vout range?

0 Austin Allen over 4 years ago in reply to Minqiu Xie

TI__Intellectual 2555 points

Hi Minqiu,

Vin is 3.6 to 6.5 and Vout is 5.5V.

Thanks!

Austin Allen

0 Minqiu Xie over 4 years ago in reply to Austin Allen

TI__Mastermind 21565 points

Hi Austin:

Typically, the current limit during the startup is 1A. So it should be OK with the condition you mentioned.

0 Austin Allen over 4 years ago in reply to Minqiu Xie

TI__Intellectual 2555 points

Hi Minqiu,

Thank you! Any thought as to where that Rload_crit comes from in Webench? I think understanding this would be helpful in putting concerns to rest.

Best,

Austin Allen

0 Jasper Li over 4 years ago in reply to Austin Allen

TI__Mastermind 46905 points

Hi Allen,

Let's discuss the issue through email and close the post here.