Power Electronics Inverting Buck Boost Converter

The input-output voltage and current relationships of the inverting buck-boost DC-DC converter are covered. Below are links to more detailed design information.
"Basic Calculation of an Inverting Buck-Boost Power Stage," by Ilona Weiss, Texas Instruments, Application Report
SLVA721A-February 2017-Revised August 2017
www.ti.com/lit/an/slva721a/slv...
"Power Topologies Handbook," by Markus Zehendner and Matthias Ulmann, Texas Instruments
www.ti.com/seclit/ug/slyu036/...
"Switching Regulator Fundementals," by Adam Castaldo, Texas Instruments Application Report SNVA559C,
September 2012, revised February 2019
www.ti.com/lit/an/snva559c/snv...
"Understanding power MOSFET data sheet parameters," AN11158, nexperia applicaiton note, Rev. 5.0 - 6 April 2020
assets.nexperia.com/documents...

[@Harshie_]

I want to design a full bridge DC-DC converter. Can you explain how to choose a MOSFET for that?

[@studentforever4805]

Thanks, professor.

[@powerelectronicswithdr.k1017]

You are welecome! -Dr. K

[@xiaoyaziy1595]

nice video thks

[@byunghoonkim4379]

Hello Prof. K. Thank you for your lecture. I have a question. How can I get a Ii=Io*D/1-D?

[@powerelectronicswithdr.k1017]

Hi Byunghoon, great question. One way to obtain this equation is to assume that Pi = Po and therefore Vi*Ii = Vo*Io. This implies that Vi*Ii = -(Vi*D/(1-D))Io. You can cancel the term Vi from both left and right hand-sides and get Ii = -D/(1-D)Io. This equation assumes a direction of current flowing from top to bottom of the load. I make comment in the video on the direction of the output current and remove the sign in the equation and thus Ii = Io*D/(1-D). In practice, this is just an estimate as there is the efficiency is not 100%, but its a great place to start your design iterations. Best wishes on your design. -Dr. K

[@byunghoonkim4379]

@@powerelectronicswithdr.k1017 Thank you for your kind explanation.

[@Sta907]

Hello,how we get Ii=Il*D?

[@howarddelosreyes463]

what is the standard value for ripple current for this converter?

[@powerelectronicswithdr.k1017]

Hi Howard, there are no standard values. Often a design will be specified with a maximum allowable ripple current, assuming that the converter is designed for continuous conduction mode (CCM). The lower the amount of ripple current as a percentage, the greater the size of the inductor required. One rule of thumb is to have the ripple current less than 40% of the average value, but there many other design factors to consider. Thank you for watching and best wishes on your designs. -Dr. K

[@vijaykdhiman1855]

hello sir, can you please explain how to find the dc component of the inductor current

[@powerelectronicswithdr.k1017]

Hello Vijay, if you watch starting at ruclips.net/video/va5uEOtGdU8/видео.html, I provide the equations for the average current through the inductor. It is Io/(1-D). Hope this helps. -Dr. K

[@RAMKUMAR-kn4po]

Hi.Please do videos about boost and buck boost design example.

[@powerelectronicswithdr.k1017]

Hi Ram, here's a link to a video on the Buck-Boost design. ruclips.net/video/va5uEOtGdU8/видео.html. If you search my channel, you will also find some videos on the boost circuit. Best wishes on your design. -Dr. K

[@yanmyomaw3276]

Is that CCM or DCM mode?

[@powerelectronicswithdr.k1017]

CCM