Looking at Continuous and Discontinuous Conduction Mode

Ғылым және технология

#214 In this video I analyze and look at the main differences between the main conductions modes found in switch mode power supplies - continuous and discontinuous conduction mode. I look at what the exact difference is between the 2 modes as well as look at how the performance of the circuit is finally impacted.
More on Power supplies:
PSU Static Output: • Power supply parameter...
PSU Dynamic Output: • Power Supply parameter...
PSU Output Noise: • Power Supply parameter...
PSU Loop response: • Power Supply parameter...
CCM/DCM: • Looking at Continuous ...
Further reading:
www.ti.com/download/trng/docs...
www.monolithicpower.com/en/th...
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Пікірлер: 31

  • @biswajit681
    @biswajit6814 ай бұрын

    I would like to request you to make video on following topics 1. Magnetics design for SMPS 2.Designing Control loop 3. Modelling of the converter

  • @al-moutazbillah3693
    @al-moutazbillah36934 ай бұрын

    I would ask you a favour... Please clarify to us how did you get this amount of knowledge in such a young age 💪, I think you have one of the best knowledge structure among other KZread engineers, please clarify the way you have followed, or the steps you have walked through to reach here 😊

  • @InTimeTraveller

    @InTimeTraveller

    4 ай бұрын

    University education and working in the field most probably.

  • @m1geo

    @m1geo

    4 ай бұрын

    Agreed. But also working in a structured way in the field. Working with people who know their stuff, too, and every day is a learning day.

  • @mihaelabortos4696

    @mihaelabortos4696

    4 ай бұрын

    Actually he has a 4 year special video where he speaks about how he got interested into electronics and how he got better at it. kzread.info/dash/bejne/iouIyKd-etevZZs.html&ab_channel=FesZElectronics

  • @Banchev
    @BanchevАй бұрын

    Very straightforward and easy to understand!

  • @MatthewStainton
    @MatthewStainton2 ай бұрын

    Just spot on, great listening and learning from you

  • @andrewmcfarland57
    @andrewmcfarland574 ай бұрын

    You are a power conversion guru. 🙂 Your use of the simulator in your explanations is very helpful.

  • @VoidElectronics
    @VoidElectronics4 ай бұрын

    Top quality explanation as always! 😁

  • @alaricsnellpym
    @alaricsnellpym4 ай бұрын

    I thought discontinuous conduction was caused by insufficient load current - so the output capacitor remains charged to the target voltage, the PWM feedback loop cranks the duty cycle down, and the inductor is "charged" with less energy so empties out before the next cycle. So you sort of need to design for a minimum load current if you want to avoid discontinuous current. Is that a correct understanding? Thanks!

  • @FesZElectronics

    @FesZElectronics

    4 ай бұрын

    Indeed, you will run the risk of DCM under low load conditions - its not avoidable.. But if you design to move the DCM lower and lower (like use a very large inductor), the supply will react slower to fast transients. In the end you need to find the usual real life load, and design for that - and accept that extreme cases are rare... stability should still be ensured under extreme conditions, but things like low emissions can sometimes be skipped :D

  • @m1geo
    @m1geo4 ай бұрын

    Nice one, Fesz! I've been on a project at work designing some complex SMPS regulators. The output voltage was desired to vary with high slew rates, and forcing continuous mode allowed for much faster negative slew, since continuous mode can sink current from the load back to the source (albeit not efficiently).

  • @FesZElectronics

    @FesZElectronics

    4 ай бұрын

    I also noticed this in some converters where there is the option to enable or disable FPWM ; with the option disabled, the converter reaction is quite slow, especially when going from very small loads; but with FPWM enabled, the reaction time is much smaller.

  • @m1geo

    @m1geo

    4 ай бұрын

    @@FesZElectronics the problem in our case was we had nearly 1000uF of output capacitance and needed to drop the voltage from say 1.2V to 1.1V very quickly. And then jump back up again.

  • @ghlscitel6714
    @ghlscitel67144 ай бұрын

    Enlightening! Thanks!

  • @bob_mosavo
    @bob_mosavo4 ай бұрын

    Thanks, FesZ 👍

  • @joejane9977
    @joejane99774 ай бұрын

    thanks again explains a lots

  • @SergiuCosminViorel

    @SergiuCosminViorel

    4 ай бұрын

    what do you mean?

  • @joejane9977

    @joejane9977

    4 ай бұрын

    i found the video helpful in my understanding of selecting diodes and inductors depending on mode of operation of power supply@@SergiuCosminViorel

  • @mohameddrissi1075
    @mohameddrissi10754 ай бұрын

    So synchronous converters making the inductor current going backward is primarly to prevent the oscillation in DCM ?

  • @ivanlam1304
    @ivanlam13044 ай бұрын

    Could you use an electronic switch to discharge the residual capacitance and prevent the LC oscillation and consequent EMI?

  • @andrew-qf4xl
    @andrew-qf4xl4 ай бұрын

    Where do u suggest we learn power electronics

  • @ranaharsh365
    @ranaharsh3654 ай бұрын

    Why the DCM is used then? Why not to use CCM in every converter? Is the choice application dependent?

  • @ahmedzafar-xp3kb

    @ahmedzafar-xp3kb

    4 ай бұрын

    ccm usually require very big inductor sizes.

  • @thewhitedragon4184

    @thewhitedragon4184

    4 ай бұрын

    If you are using non-synchronous converters at low current, they'll tend to be run at DCM. So it's more of a "it just goes into it naturally" then of a "I want it in DCM". Another reason you might want DCM is that it algebraically degenerates the coil, reducing the system order by 1. Running a converter in DCM is a headache but a lower order system (which should be a first order system in this case) is easier to stabilize. Finally, DCM is just more efficient at low currents but its efficiency drops off at higher currents. The opposite goes for CCM. The down side of course is the fact that DCM is highly dependent on the load current, it's ripple is higher, and it radiates EMI so you win some of you lose some.

  • @InTimeTraveller

    @InTimeTraveller

    4 ай бұрын

    @@thewhitedragon4184 can you explain a bit more on how it reduces the order of the system? How does DCM affect the transfer function of the system?

  • @thewhitedragon4184

    @thewhitedragon4184

    4 ай бұрын

    @@InTimeTraveller In DCM operation coil current goes to 0 and starts from 0 each cycle. This means that in DCM the coil has fixed starting conditions, and thus doesn't add a pole to the system. Basically, a coil in DCM is a coil with a current source of value 0 in series. Analogous to a capacitor with a voltage source in parallel, such a circuit does not add poles to the overall transfer function

  • @thewhitedragon4184

    @thewhitedragon4184

    4 ай бұрын

    It should be noted that the pole isn't really gone but it is pushed closer to the switching frequency which means that we can usually neglect it in averaged models of converters

  • @cyrus-music
    @cyrus-music4 ай бұрын

    And boundary mode?

  • @SergiuCosminViorel
    @SergiuCosminViorel4 ай бұрын

    more accurate, to say it is damped oscillation, not oscillation

  • @BartKus
    @BartKus4 ай бұрын

    69th thumbs up. aww yiis.

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