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  1. Closed: Re: Adding an LC post filter can make an SMPS unstable....use RC filter instead?

    Yes, put damped C's on your power supply, and damping in the control loops, 3rdly specify max capacitance load, it is generally only a problem at light load / no load - as at full loads the R...
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    Closed: Re: what should i use as a ac source?

    A variac and an isolating transformer ...
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    Closed: Re: Regulating without load

    at start up with no load these simple bang-bang reg's can go over volts and sit there for a long time until the leakage current on the electro brings them down ...

    a 150k resistor from the...
  4. Closed: Re: Adding an LC post filter can make an SMPS unstable....use RC filter instead?

    If you load a converter with a less than critically damped LC stage, where the Fo is close to or less than the crossover freq of the converter - then yes you are asking for problems - ...
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    Closed: Re: P-channel Mosfet inverting control

    The 1k should be in the Drain of Q5 ... else it affects the gate drive volts of Q5 ...
  6. Closed: Re: Calculating capacitor ripple current in output filter of DCDC module?

    just for clarity, Tan-delta is used to calc losses, capacitor VA x tan-delta = watts

    i.e. 2Vrms x 2A rms = 4 VA in the cap x tan-delta of 0.1 = 400mW in the cap ...
  7. Closed: Re: Calculating capacitor ripple current in output filter of DCDC module?

    the resistance of the cap at 750kHz ( it will be higher than ESR min at resonance ) will add vectorially to the XL at 750kHz to give a Z some what higher than the ESR...
  8. Closed: Re: Calculating capacitor ripple current in output filter of DCDC module?

    just a note, most electro's are self resonant from 50 - 100kHz, i.e. above this they are inductors, they provide bulk storage for low frequencies only, if the Vicor sw freq is 750kHz, then...
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    Closed: Re: uc3842/3843 Vcc problem in smps.

    where are you buying for control IC's from ... ?
  10. Closed: Re: Calculating capacitor ripple current in output filter of DCDC module?

    V ripple is given as 1Vpp ( at a min load ) this is 350mV rms, most of the current ripple generated by the converter is soaked up by the 11uF internal MLCC's

    you don't know the operating...
  11. Closed: Re: Need to ensure SMPS output filter has at least 10mR of ESR...use "ESR resistor"?

    Say you use 1000uF on the o/p, ues 2 x 470uF low ESR

    put 10 milli-ohm in series with one of them - job done - it will be stable ...
  12. Closed: Re: Rectifier diodes with bypass capīs & gounding speaker basketīs

    power in snubber resistors is approx = C. Vpk^2 F for 15-0-15 Vpk ~ 42Vpk, F = 50/60 Hz, say C = 100nF, then power in R = 10mW for 60Hz, for any R up to 85k-ohms ( above this...
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    Closed: Re: uc3842/3843 Vcc problem in smps.

    Yes the 200W light bulb is only a few ohms when cold - so unless your soft start is ~ 30 seconds, you will never get it going ... even then you likely won't be able to supply the current to...
  14. Closed: Re: Inductance of coile dup cbale on winch (twisted pair or just two strand)

    agreed - twisted pair and side by side is essentially the same thing, for send & return coiling has no effect ...

    - - - Updated - - -

    as to the drones - eventually the weight of the wire...
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    Closed: Re: Smps design with UC3844 for 300V /0.5A

    transformer design and phasing of windings is critical to the flyback circuit working - as is making sure the feedback is working before applying serious power ...
  16. Closed: Re: Rectifier diodes with bypass capīs & gounding speaker basketīs

    if you are happy putting snubbers across the 15Vac - then go for it ...
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    Closed: Re: uc3842/3843 Vcc problem in smps.

    there is no limit on the duty cycle if the feedback, via opto, does no work properly. There is a 36V zener inside the chip on the Vcc line - but this is low power ...

    if the feedback isn't...
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    Closed: Re: uc3842/3843 Vcc problem in smps.

    the problem here is lack of cognitive function, without a zener the Vcc will be exceeded if the IC does not start ....
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    Closed: Re: uc3842/3843 Vcc problem in smps.

    Simple logic tells you that if the IC fails through over-voltage it is likely that over-voltage will make it to the gate pin, holding the fet on, and/or destroying the gate structure, again...
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    Closed: Re: 1.5kw DC to DC Boost Converter Circuit

    OK - it's pretty ugly gate drive - but cannot say more without a schematic ...
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    Closed: Re: uc3842/3843 Vcc problem in smps.

    As above - there is no zener to limit the volts on the chip supply ....
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    Closed: Re: would an engineer use this equation?

    temp rise is a function of the watts dissipated in the Tx and the surface area and shape of the Tx and any cooling air flow - there is no simple formula for this only experience ...
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    Closed: Re: uc3842/3843 Vcc problem in smps.

    Sorry but none of the documentation provided helps to solve your issue - schematic please - it could be that you are running off an isolated transformer and then the gnd of the scope probe is...
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    Closed: Re: would an engineer use this equation?

    R = rho. L / Area is what an engineer would use, watts dissipated = R . i^2 ( for rms current in the wire )

    then there is an added heating effect from a close wound coil of wire, ...
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    Closed: Re: 1.5kw DC to DC Boost Converter Circuit

    I wouldn't worry about that too much - - is that the gate drive ... ?
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