The inner works of Peak Current Mode (PCM) control 

Thank you prof. Sam for the interesting content! Your videos are so fundamental like the proper alphabet of electronics. Nice part with chatGPT, clever words.👍

Thank you for your videos!

Interesante, saludos desde México.

Oh such an underestimated content. My 100-th like is yours)

Thank you Sam. This PCM method seems attractive at first sight, but in my opinion there are a number of issues with it that put constraints on the situations when you can use it : 1) As the wave forms at 2:00 shows, the current detection needs to be very fast and very reliable. If the PWM frequency is 100 kHz, then the peak current detector needs to be at least a factor or 10x faster, so needs to respond within 1 usec or so. If it misses even one cycle, or is a bit too slow, the loop locks up and your converter burns itself out. And since this happens very fast, any sort of second layer of safety is going. to be harder to implement too. Not very 'fail-safe' in my opinion... 2) As the schematic at 3:00 shows, this circuit only works if the 'logic' gnd is the same as lower rail of the converter. This is not always the case, especially not with the recent trend to put isolation devices between the power train and the control logic. 3) Very often, a digital controller (MCU) is used to provide the PWM signals to the switches, and that means we want to use PCM, we need another ADC in the loop, and that one ALSO needs to be very fast (1 usec or so). 4) Finally a note : The Duty-Cycle issue in PCM (diagram at 6:00) that Prof. Middlebrook first reported about in my opinion is simply a loop 'gain' dependency in the feedback loop. After all, with the resistor-in-lower-switch current detector we are only measuring the current when the switch is on. So the loop gain increases linearly with the duty-cycle. Is that a fair statement ? Thanks again for reporting this interesting method of implementing a current loop, but may it be that the application of this method is not very often used any more now that PWM control with an MCU is more common ?

Another great video! I was hoping you would also show a practical implementation of how YOU apply slope comp using a generic controller IC, for instance the UC384X

Thank you!

Hi sir how are you...long time no videos..

Sir i have some doubts other than the PWM generation of Peak current control what are the other parameters gets affected due to the short circuit condition in peak current mode control ? like the which parameters gets affected due to that high rate of change of current sir ?

Regardless the AI will be adopted or discarded in the future, the IC manufacturers will get the benefit, provided the huge computation the AI requires.

awesome!

Is there any calculation to calculate the values of Capacitor and resistors in compensation network

Excellent video, thanks. So this is why you have the ramp pin on a PWM driver. Is it not also used to generate the square wave output?

Hi Prof. Interesting results for LG. Wonder for LG for the current feedback amplifier. Can we use the same method as a voltage feedback amplifier? What about if you have one inner current feedback amplifier with one outer voltage feedback amplifier. I understand that your video is DC/DC . But what about the current feedback amplifier with outer voltage feedback? Thanks for answering in advance

professor,what's V(EXC) of B4 in your LTspice simulation in your presentation？

is there a advantage in having +slope compensation in the current reading vs -slope on the reference? Also what is a good starting point for the slope? -1V /ms ? or this value is determined later with experimentation /simulation ? Regarding this mode of operation can it reach 100% duty cycle? asking since besides the current sensing method i dont see why not ( unless it is a FET driver limitation) ?

Sir but the slope compensation method doesn't effective(precise and accurate ) for PCM used for all application.(specifically fr PCM in Current Limiting purpose in Solid state Circuit breaker application),

More ltspice please 🎉

👍🙏❤️

AI has reached a great level in emulating a human interaction and it is syntactically impeccable...but as some humans It invents or gives generic answers when the argunent is too specific and there Is not a clean database on the matter.