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  1. 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...
  2. 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...
  3. 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...
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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...
  5. 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...
  6. Closed: Re: Voltage input to BLDC inverters on tethered drone?

    Thanks, i am wondering if it can be done the other way concerning the motors.......ie, high voltage and lower current?

    - - - Updated - - -

    Hi
    Would you agree that the old addage that “Motor...
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    Closed: Re: convert voltage control to current control

    We have discussed here how Current mode control can’t be used in a half bridge SMPS.
    However, the following document states that a “Current Doubler rectifier “ can be used with a Half Bridge...
  8. Closed: Re: Regulating temperature of mains connected heating element: Skipping mains half cy

    Thanks, no we didnt, but we will parallel them.
  9. Closed: Re: Regulating temperature of mains connected heating element: Skipping mains half cy

    Thanks, we will end up using back-to-back power FETs with isolated drive due to the total 32A of current. We will parallel them.

    What worries us is that I can see that if our zero-cross isnt pin...
  10. Closed: Re: Need to reduce drain voltage spike in LM5019 Buck converter

    Thanks,
    Ill try the "common mode" test
  11. Closed: Re: Voltage input to BLDC inverters on tethered drone?

    Thanks, i suppose there is no power supply on the "tethered drone"?...just the BLDC inverters...which must us high voltage IGBTs?....

    Maybe somne just have a rectifier bridge and smoother to feed...
  12. Closed: Voltage input to BLDC inverters on tethered drone?

    Hi,
    Regarding tethered drones such as the LIGH-T 4, which is rated at 1.2kW….
    https://elistair.com/ligh-t-tethered-station-for-drone/

    Do you know what voltage the BLDC motor inverters are ...
  13. Closed: Re: Need to reduce drain voltage spike in LM5019 Buck converter

    Thanks, it seems a little odd that in the datasheet "ABS MAX's" it says the SW pin should be no higher than "vin+0.3v".......whereas the vin pin can be up to 100v......so why cant the SW pin be...
  14. Closed: Need to reduce drain voltage spike in LM5019 Buck converter

    Hi,
    We are using the LM5019 for a Buck converter
    Vin = 60V
    Vout = 12V
    Iout = 7mA

    We notice a spike on the LM5019 drain voltage of 20V in magnitude...as in the attached. This surprises us, as...
  15. Closed: Re: ZMR330: 3V3 Linear regulator needs diode connected cathode to input voltage?

    Thanks, i mean a diode connected anode to output, cathode to input...
    in the old days, such a diode was always needed to protect the regulator in those cases wherever vout gets bigger than vin.
  16. Closed: ZMR330: 3V3 Linear regulator needs diode connected cathode to input voltage?

    Hi,
    Question as per title.

    ZMR330 datasheet
    https://www.diodes.com/assets/Datasheets/ZMRSERIES.pdf

    ..the datasheet doesnt say such a diode is needed. Would we need one.

    We are using it...
  17. Closed: Re: Resistor at input to high side current monitor IC

    Thanks yes,
    We have Rsense = 0R75, RA=1k and RB=3k3.

    I made RP=43k and readings (voltage on RB) were badly inaccurate.
    Now that we have RP=RA, the readings are good....

    ..the problem is, as...
  18. Closed: Resistor at input to high side current monitor IC

    Hi,
    Should resistor RP on page 1 of the HV7802 datasheet ideally be equal to the value of RA?

    HV7802 datasheet
    http://ww1.microchip.com/downloads/en/DeviceDoc/HV7802%20A062813.pdf
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    Closed: Scraping PCB causes ESD damage to IC?

    Hi,

    In the attached schematic, I had been soldering components on and off the board many times, in the vicinity of this circuit. On some occasions, I accidentally used a plastic handled metal...
  20. Closed: Re: 16A 250V switch rated for 10000 ops at mains peak or zero cross?

    i agree its low energy, though cant it spark off oxidation in the contacts? Also, the damage is cumulative, and the contact chrome coating is microscopically thin.
    Or would it be said that contact...
  21. Closed: Re: 16A 250V switch rated for 10000 ops at mains peak or zero cross?

    Thanks, by "contact opening time" you are speaking of "contact bouncing time"?

    I believe we would agree that an ideal world resistive circuit, with no inductance, would not suffer any contact...
  22. Closed: 16A 250V switch rated for 10000 ops at mains peak or zero cross?

    Hi,
    The below switch says its rated for 10000 operations. But does that mean 10000 operations with the switching happening at the zero crossings, or 10000 ops with switching happening at mains peak?...
  23. Closed: Re: Is this the reason there's so few 2 Transistor Fwd Sync Rect controllers?

    Actrually, adding RCD clamps across the sync FETs does solve the problem with the LT1681/LTC1698 combo. (As attached LTspice sim and pdf.)
    In fact, the lack of the usual fast current sense (with...
  24. Closed: Re: Opamp buffer with 400nF output capacitance going unstable?

    Thanks, what we actually have on the pcb is the schem in #18 [but the 2k7 (R5) is actually a 100n capacitor]

    ...we are currently wangling it to be as the schem in #17 (by not fitting the bjt and...
  25. Closed: Re: Opamp buffer with 400nF output capacitance going unstable?

    Thanks, yes, Thanks for them, but we dont have money for a pcb respin...and so are trying to wangle what we have.
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