TPS62811-Q1: Buck Regulator Worst Case Calculations

Hello Siburaj,

Thanks for reaching out to us.

Just give me until Thursday to respond to your queries.

Best regards,

Excel

Hello Siburaj,

I suggest to use the Webench tool for the power loss analysis (see the link below).

https://www.ti.com/design-resources/design-tools-simulation/webench-power-designer.html

Thank you.

Best regards,

Excel

I will use webench.

But is there any equation available to do the same. I am planning to do worst case analysis using Mathcad.

Hello Siburaj,

You can consider the app note below for calculating the power losses on the buck converter. I hope the document will help.

https://www.ti.com/lit/an/slvaeq9/slvaeq9.pdf?ts=1665007621996

Best regards,

Excel

Hi Excel Redigor, 

Thanks for sharing the document. I have checked this document and many parameters to calculate the losses are missing in the datasheet. Is there any other document available having all those missing parameters. For example, to calculate switching loss we need to know the tr and toff which is missing in the datasheet. Can you help me to get those parameter values.?

Hello Siburaj,

The tr and toff parameters are confidential data, so we cannot share them. I hope you understand it's the company's policy that prohibits the sharing of this information.

Best regards,

Excel

Hi Excel Redigor,

Thanks for your reply. 

Can you suggest me a solution on how can I move forward to do this worst-case calculations, if parameter values are confidential?

Hello Siburaj,

Give me until Thursday to respond to it. I might be able to find a workaround to approximate the worst-case IC power dissipation. Hoping the timing is fine with you.

Best regards,

Excel

Hi Excel Redigor,

Thanks for your response.

Thursday is fine.

I am doing worst case analysis for multiple regulator parts from TI for our upcoming design.

Best Regards,

Siburaj D.S.

Hello Siburaj,

Please see the attached file for proposed worst-case IC power dissipation calculation.

Let me know thoughts.

Best regards,

Excel

IC_Pd worst-case sample calculation.pptx

Hi Excel,

Thanks for sharing the alternate method to do the worst case calculation.

I have one more question related to this part.

I want to calculate the worst case power consumption of resistor connected in COMP/FSET pin. We are using 8.06K resistor. 

Can you share a method to do worst case power consumption of this resistor.

Regards,

Siburaj D.S.

Hi Siburaj,

I will share the data via private message. I hope it is fine with you.

Best regards,

Excel

Hi Siburaj,

Just a gentle reminder.

Did you receive my private message about RCF power consumption? And do you still have other queries?

Thank you.

Best regards,

Excel

Hi Excel,

I need one more data from your side for this regulator.

Can you share me the IOH and IOL values for the Enable pin of this regulator?

Best Regards,

Siburaj D.S.

Hi Siburaj,

I'm not sure if I understand your question correctly. Are you asking about the Enable pin threshold? If yes, the Enable pin tolerance is indicated in the datasheet (see figure below).

Let me know if my response addresses your queries.

Best regards,

Excel

Hi Excel,

Sorry for the typo mistake. Can you share me the IIH and IIL values of the enable pin of this regulator ?

Best Regards,

Siburaj D.S.

Hello Siburaj,

The EN pin has a maximum leakage current of 150nA over the entire Vin and temperature range (see table below). I hope I was able to address your query.

Best regards,

Excel

Thank you Excel.