TPS650830: Design equations 3 and 4.

Thomas Horwitz

Part Number: TPS650830

On page 131 of the TPS650830 datasheet there is equation 3 for calculating Rcs. What value is used for Itrip in this equation? Also equation 4 on the same page uses values Vcsmin and Vcsmax. Where do these values come from?

over 6 years ago

0 Jayanth Kruttiventi over 6 years ago

TI__Intellectual 1360 points

Thomas,

Itrip is the value of current limit you would like to set for each regulator. It should come from your design. In equation 4, Vcsmin and Vcsmax values are VILIM min and max value from the spec tables. Typical values are betweeen 0.2V and 2V.

Jay

0 Thomas Horwitz over 6 years ago in reply to Jayanth Kruttiventi

Prodigy 225 points

I thought Iocl in equation 3 was the current limit of the regulator.

0 Thomas Horwitz over 6 years ago in reply to Thomas Horwitz

Prodigy 225 points

What is the difference between Itrip and Iocl?

0 Jayanth Kruttiventi over 6 years ago in reply to Thomas Horwitz

TI__Intellectual 1360 points

sorry for the confusion. Iocl is the current limit and Itrip(Ilim) is the internal current sourced across Rtrip(Rcs) resistor. Itrip value is 50uA. We need to make sure that Rtrip is choosen such that Vlim falls between 0.2V and 2V.

We will make a note to update the spec.

0 Thomas Horwitz over 6 years ago in reply to Jayanth Kruttiventi

Prodigy 225 points

In equation 3 there is a variable RDSon. Is this the on resistance of the bottom FET? Also in equation 5 is the variable RDSon the on resistance of the top FET?

0 Jayanth Kruttiventi over 6 years ago in reply to Thomas Horwitz

TI__Intellectual 1360 points

yes, equation 3 is low side FET resistance and equaiton 5 is high side FET resistance. I have sent you a freind request and once you accept, i can send you excel calculators to measure resistance values and inductor and capacitor values as well.

Regards,
Jay

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TPS650830: Design equations 3 and 4.