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  1. Replies
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    1,957

    Closed: Re: 1.5kw DC to DC Boost Converter Circuit

    Please try my course in SMPS, it helps with such details

    https://drive.google.com/open?id=0B7aRNbu3Fes4TU92Mkw3YlA3ams
  2. Closed: Accurate mains zero cross detector circuit without optocoupler

    Hi,
    We need an accurate mains zero crossing detector, but cannot use "wear-out" components such as opto-couplers. Do you agree that the attached circuit will be very good?, since it uses matched...
  3. Replies
    2
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    106

    Closed: Where are resistors on 8 x resistor array?

    For the “CAY-16 J8” resistor (8 resistors on a chip), do you know if the resistors are where the “concave” bits are, or where the “straight” bits are?
    ...
  4. Closed: Re: Ramping a reference voltage up from, or down to zero volts, over ~200us

    Thanks,
    Klaus your solution looks great, i will try it now.

    I had come up with the attached (LTspice sim and pdf schem) but it is not as good as yours since it needs a +/-5V supply, and the ramp...
  5. Closed: Re: Ramping a reference voltage up from, or down to zero volts, over ~200us

    Thanks, i think we will need a negatiove supply to get a good ramp down from 0.5V..
  6. Closed: Re: Circuitry to make Paralleled Buck converters share current.

    Thanks, this sounds excellent....i like LLC for high voltage outputs like 150V+...because the LLC suffers no overvoltage ringing to its secondary rectifiers...unlike PSFB or FB.

    So anyway, this...
  7. Closed: Ramping a reference voltage up from, or down to zero volts, over ~200us

    Hi,
    Please assist us in ramping a reference voltage down to zero volts, or back up to the reference voltage. This being done at random times, on demand. The ramp should be over some 200us. It...
  8. Closed: Re: Circuitry to make Paralleled Buck converters share current.

    Thanks, so you are saying that the feedback loop bandwith of the "master" and the "slaves" of the attached could all actually be the same, and this wouldnt give problems?
  9. Closed: Re: Circuitry to make Paralleled Buck converters share current.

    Thanks, yes I agree with you in the specific example which you give here..ie the “inner current loop of a current mode controller”…..but isn’t the situation of the master-slave approach detailed by...
  10. Closed: Re: Circuitry to make Paralleled Buck converters share current.

    Thanks Klaus,
    Yes the “master-slave” method, with master regulating voltage , and slaves regulating to the master’s current , is like in the attached….unfortunately this method can mean noise...
  11. Closed: Circuitry to make Paralleled Buck converters share current.

    Hi
    The attached (LTspice sim and pdf schem) is two paralleled Buck converters.
    Please assist us in making out the circuitry required to make these Bucks share current equally between them.
    ...
  12. Closed: Re: Voltage input to BLDC inverters on tethered drone?

    good questions, we dont know though, since this has just been leaked.....weve only heard this little bit for now.
    I like the idea of the "spilt up LLC"......this was the modus operandi of isotera,...
  13. Replies
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    Closed: Re: L1 and C1 value for EMI filter design ?

    if you want a general idea, (theres no real formulae for it), then think of your power level, ...says its a 60w flyback...then check out app notes for 60w flybacks and see what they are using....or...
  14. Closed: Re: Voltage input to BLDC inverters on tethered drone?

    For a 56kg tethered drone consuming 12.5kW and using an 800vdc feed from the ground based power supply…what voltage would you say was chosen for feeding to the BLDC motor inverters?
    (i was told it...
  15. Closed: Re: LLC converter vs Dual cascaded Buck….1000V to 48V at 500W output…no isolation ne

    Thanks, this is a good point, because I can imagine that if there are say eight or so open-loop synchronous Buck converters supplying the same load in parallel…then do you believe there can be a...
  16. Closed: Re: LLC converter vs Dual cascaded Buck….1000V to 48V at 500W output…no isolation ne

    Thanks, no testing as yet...though i believe that we will be clewar of current hogging problems with this parallel open loop Buck.
    I stepped the load from full to zero and VV in the sim and it...
  17. Closed: Re: LLC converter vs Dual cascaded Buck….1000V to 48V at 500W output…no isolation ne

    The following looks good for high input voltage…..its two LLC converters in series, but they share the one transformer and the one resonant inductor....
  18. Closed: Re: LLC converter vs Dual cascaded Buck….1000V to 48V at 500W output…no isolation ne

    yes the sim works, but there are some ~3ns spikes in the sync fet up to 20A, i presume this could be a simulator thing though...maybe the internal diode in the sync fet is very slow.
    I put some...
  19. Closed: Re: LLC converter vs Dual cascaded Buck….1000V to 48V at 500W output…no isolation ne

    Hi
    Thanks, the attached (schem and ltspirce sim) is a Dual Buck with the last stage with a sync fet and at 50kHz.
    I added a comparator to the COMP pin of the controller …this being done so that...
  20. Closed: Re: Voltage input to BLDC inverters on tethered drone?

    Thanks, i appreciate they wont ever generate back, and will always be running significant power, but wondered what generally the total power range (ie percentage of max range) is likely to be whilst...
  21. Closed: Re: LLC converter vs Dual cascaded Buck….1000V to 48V at 500W output…no isolation ne

    Thanks yes, the Dual cascaded Buck…all from one controller…..this looks a good shot. No problems with control loops fighting.
    I could only do it from 800v in LTspice because theres no 1kv diodes in...
  22. Closed: Re: Voltage input to BLDC inverters on tethered drone?

    Thanks,
    If a drone is up in the sky, and is then brought down to land.......then whilst it is coming down, what power are the motors running at?.....roughly what percentage of full power?
    I assume...
  23. Closed: LLC converter vs Dual cascaded Buck….1000V to 48V at 500W output…no isolation needed

    Hi,
    Do you agree that the LLC converter would be more efficient for the above case?
    Consider synchronous rectifiers in each case.
    The Buck would be a Dual cascaded Buck so that Duty cycle was...
  24. Replies
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    Closed: SMPS for 5000W can be a Full Bridge

    On page 9 of the book “Power supply design, Volume 1 Control” by Dr Ridley, he states that a Full Bridge converter is good for power levels from 200w to over 5000w.
    Most places where I have worked...
  25. Closed: Re: Voltage input to BLDC inverters on tethered drone?

    Thanks, we are looking for a offtheshelf 200w-500w BLDC motor which takes Vin of 400V or more but cannot find one, do you know why this is?
    There are millions with voltages up to 48V, but almost...
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