Thank you for the great video and look forward to the multi-phase switching regulator video. If it's available already, can someone please share a link? Couldn't find it in the channel. THX!
How to find a frequency of required regulator that my power regulator have this much of “xy” frequency for my certain load. Let suppose I have my load ICs which has 3.3v and 2A of rating. Now what parameters I have to look in data sheet of load as well as when I finalise power converter. It will be really helpful if you can provide in details. I have gone through paper which you have attached but in that external LC freq is given. But how to select power regulator of what frequency it should have I want to know that. Thanks for all your knowledge videos. I followed most of them
The power regulator does not source AC power, it sources DC power that charges up the capacitance in your PCB. The capacitance in your PCB is what provides AC power out to some high frequency range. The frequency value in your regulator that you are referring to is the control loop transfer function, which reaches into the MHz range. This is not often specified in datasheets in part because it depends on the PCB layout of the regulator, so it is something that needs to be measured. This specification is important in VRMs for large processors, which are often multiphase regulators that source high current (10’s of Amps), it is not something you would commonly need to worry about in lower current systems.
Other two videos were much stronger. Little bit of a red herring at the beginning with the discrete vs. integrated solutions in schematic. This video emphasizes the complexity of switching regulators while not making them more accessible to new players, could end up pushing people away.
You can adjust sw freq with capacitor Ct. This is a very cheap converter and only has a comparator, not an error amplifier so output ripple is worse than the more expensive ones.
Why would we cascade with buck and ldo and not just let the switching regulator go straight to the desired voltage? Is the idea that the ldo get rid of some of the noise?
You could do that if you needed to also use the SW regulator voltage. Also the LDO can provide extra noise reduction as these devices have high PSRR values. Many ICs will have an LDO built into the input power stage for this purpose.
Another reason is that the parasitics in an LC filter stage can add new poles into the output filter's transfer function, which could then introduce a new oscillation if the switching stage has fast edge rate. Once you get to high currents, you have to use physically larger components which moves those poles to lower frequecies, so they become easier to excite at lower PWM edge rates. LDOs aren't always the solution there however because at high average DC current the LDO will get really hot, so you would want to add some very small resistance in series with your LC filter elements to provide some damping. You'll see this done on some reference designs, particularly on the output filter capacitors. The idea is to add some damping to bring the transient response closer to being critically damped, so then you don't get a voltage/current strong oscillation reaching the load. This is they type of stuff you can simulate in SPICE.
This is why altium is the best
Too informative, can't wait for upcoming videos with such deep explanations 🙌
More to come!
please make a video how create a good PCB layout for switching regulator
Yes, this would be great.
We have a pair of videos on that:
Part 1: ruclips.net/video/6AEUxY9QipI/видео.html
Part 2: ruclips.net/video/5q4on8L1vKo/видео.html
Nice vids. Waiting for that next one to come out!
Thank you for the great video and look forward to the multi-phase switching regulator video. If it's available already, can someone please share a link? Couldn't find it in the channel. THX!
We can´t realize how lucky we are to have internet nowadays, and free acces to all this information.
Great info
How will a synchronous and asynchronous switching regulator work can u explain that concept as well.
How to find a frequency of required regulator that my power regulator have this much of “xy” frequency for my certain load.
Let suppose I have my load ICs which has 3.3v and 2A of rating. Now what parameters I have to look in data sheet of load as well as when I finalise power converter.
It will be really helpful if you can provide in details.
I have gone through paper which you have attached but in that external LC freq is given.
But how to select power regulator of what frequency it should have I want to know that.
Thanks for all your knowledge videos. I followed most of them
The power regulator does not source AC power, it sources DC power that charges up the capacitance in your PCB. The capacitance in your PCB is what provides AC power out to some high frequency range. The frequency value in your regulator that you are referring to is the control loop transfer function, which reaches into the MHz range. This is not often specified in datasheets in part because it depends on the PCB layout of the regulator, so it is something that needs to be measured. This specification is important in VRMs for large processors, which are often multiphase regulators that source high current (10’s of Amps), it is not something you would commonly need to worry about in lower current systems.
thank you
You're welcome
Other two videos were much stronger. Little bit of a red herring at the beginning with the discrete vs. integrated solutions in schematic. This video emphasizes the complexity of switching regulators while not making them more accessible to new players, could end up pushing people away.
Not a bad video for layout technicians, but kinda rough if switching regulators were a new concept from the first video.
You can adjust sw freq with capacitor Ct. This is a very cheap converter and only has a comparator, not an error amplifier so output ripple is worse than the more expensive ones.
Why would we cascade with buck and ldo and not just let the switching regulator go straight to the desired voltage? Is the idea that the ldo get rid of some of the noise?
You could do that if you needed to also use the SW regulator voltage. Also the LDO can provide extra noise reduction as these devices have high PSRR values. Many ICs will have an LDO built into the input power stage for this purpose.
Another reason is that the parasitics in an LC filter stage can add new poles into the output filter's transfer function, which could then introduce a new oscillation if the switching stage has fast edge rate. Once you get to high currents, you have to use physically larger components which moves those poles to lower frequecies, so they become easier to excite at lower PWM edge rates. LDOs aren't always the solution there however because at high average DC current the LDO will get really hot, so you would want to add some very small resistance in series with your LC filter elements to provide some damping. You'll see this done on some reference designs, particularly on the output filter capacitors. The idea is to add some damping to bring the transient response closer to being critically damped, so then you don't get a voltage/current strong oscillation reaching the load. This is they type of stuff you can simulate in SPICE.
@@Zachariah-Peterson Awesome, thanks a lot for the clairification