Module 2: Introduction to Control Algorithms in Switching Regulators

An overview of how switching is controlled in switching regulators. Focuses on three popular control algorithms: constant on-time, voltage mode control and current-mode control.

[@joeygodiska4404]

Awesome video, very well done. "Noise margarine" made me laugh!

[@agstechnicalsupport]

Thank you for the great tutorial on control algorithms in switching regulators ! It would help if you use a pointer.

[@davidcano90]

Thanks Maxim and Thank Professor Mammano. I have two questions:
1) Analyzing the type ii compesator, what relationship have the R1 shown at 15:36 (let's call it simply "R") and R1 and the Rb shown at 17:07. Is it R the parallel of R1 and Rb?
2) How can I do the slope compensation circuitry without loading the RC pin of a CMC controller which does not have slope compensation pin?
Thanks for reading and for your help.
Best regards.

[@maximintegrated]

Thanks for your questions, David. Here's our input:
1. R1 and Rb form a voltage divider to set the proper output voltage. Vo = (R1/Rb + 1)*Vr; where Vr is the reference voltage of the feedback loop error amplifier
2. To do slope compensation, please use a controller that has this feature

[@davidcano90]

@@maximintegrated Would it be different if I not only use R1 and Rb (for the voltage divider) but If I include a include a new resistor which is connected to the inverting input of the OAmp and the connection point of these resistors, so that the PI gain is set exclusively by R2 and the new resistor? Thank you for your help.

[@maximintegrated]

@@davidcano90 You have to use R1 to set the control loop gain. You can use the new resistor to set the ratio for the correct DC output voltage
For additional questions, it would be great if you could consult our Tech Support resources. We have an online knowledge base with Q&As as well as Tech Support experts who can help: maximsupport.microsoftcrmportals.com/en-US/support-center/ Thanks again!

[@robertodilorenzo5086]

Current-mode control is your point of strength, but it does not explain how you create the current sensing. At minute 9:00 of the video, the diagram shows a wire goes on the Rcs resistance, I think is a sensor that indirectly reads the current ripple. Is it correct?

[@maximintegrated]

Yes, the loop between the power switch and the inductor denotes a current sensing device (a current sense transformer) that terminates on Rcs. So, Vcs is a voltage representing the switch current information with a ratio scaled by Rcs and the current sense transformer turns ratio). By the way, there are various ways to sense the switch current. Current sense transformer are used only in high power system. Most integrated buck converter solutions that Maxim makes use different, proprietary techniques to sense the switch current.

[@robertodilorenzo5086]

​@@maximintegrated The techniques to sense the current are two o three, you can use electromagnetic techniques or self-matched filter, ect... By the way you can delete an external pad (for integrated buck converter), with only two commercial techniques, in the other solutions you need an external pad to sense the current.

[@ildem5327]

Hi, will this control algorithm can be applied to a boost converter?Will there be any changes in its advantages and disadvantages? Do you have a video or related literature of using the control algorithms for boost converter?Thank you.