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  1. Replies
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    Closed: Make component in LTspice

    Hi
    Do you know how i can make a single component out of the attached LED string?...we are using loads of them in the sim and its taking ages to run.
  2. Closed: Highest practical power of LED driver off 240VAC?

    200W Offline LED driver, 240VAC input. Done with Power factor corrected Boost then LLC.
    Output 250V, 0.8A
    Efficiency would be 93%....but do you agree, that a 1kW LED Driver is not really...
  3. Closed: Re: 500W-1kW offtheshelf offlien SMPS's with no fan (240VAC)

    Thanks, they have all got open grills in the top of the enclosure. It would be interesting to see how totally enclosed power supplies compare...eg ones with IP66 rating.
  4. Replies
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    Closed: Thermal vias in pads..plated over

    Hi,
    Our PCB manufacturer offers us thermal vias in dpak pads, and plated over on top and bottom sides. They are filled with epoxy.
    How come the air that must get trapped inside them doesnt get hot...
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    Closed: Re: Solar panel regulator

    yes your panels could give up to 88.7vout, so you need a buck battery charger to go between the solar panel and the battery.
    So you just need a step down converter for 50-90vin down to 10-14Vout....
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    Closed: Re: DC DC converter for EFB-REV1

    if you want you can use an RT6208 based buck converter. The datasheet tells you how to set it up.
  7. Closed: 500W-1kW offtheshelf offlien SMPS's with no fan (240VAC)

    Hi
    We would like to see examples of offtheshelf SMPS's of 500W up to 1kW that have no fan cooling, to look at the sizings.
    By "no fan", we mean no fan inbuilt into them, and no fan meant to be...
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    Closed: Drinks machine job = SMPS design?

    Hi,
    Just got the JD for a electronics job making drinks machines.






    Are the power supplies likely to be bought in from China, or they design them themselves?.....what voltage do you think...
  9. Closed: Re: Fault mode of synchronous recrifier IC with BCM flyback

    its in BCM but there is a minimum on time, so in certain situations, it will be in DCM.
  10. Closed: Re: NPN is bahaving as oscillator when used with DALI comms bus

    Thanks, by the way, the following circuit also works fine, but we dont want a bulky opto in there as we dont need the isolation.
    (ltspice and pdf attached)
  11. Closed: Re: NPN is bahaving as oscillator when used with DALI comms bus

    Thanks, On the previous board, the original circuit of the top post (without optocouplers) worked absolutely fine, but we did not have the bridge rectifier then.

    - - - Updated - - -

    we are ...
  12. Closed: Re: NPN is bahaving as oscillator when used with DALI comms bus

    Thanks to all, what about the following adjustment to the DALI receiver circuit?…now we have reduced the gain of the first NPN stage, making it a follower. We have also made the base_emitter resistor...
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    Closed: Re: Using MOSFET as load for voltage regulator?

    here is an ltspice sim of a current regulator that you could find useful
  14. Closed: Re: NPN is bahaving as oscillator when used with DALI comms bus

    Thanks, No optocouplers. There are no other receivers on the dali bus.
    The 60W SMPS has an earth connection, but does have full isolation between primary and secondary…the dali receiver is...
  15. Closed: Re: NPN is bahaving as oscillator when used with DALI comms bus

    Yes....here is a scope shot of what the noise looks like at RA3.........top is what we should see, bottom is what we get.
    The micro isnt responding to the comms...presumably due to this noise
  16. Closed: Re: NPN is bahaving as oscillator when used with DALI comms bus

    Thanks,
    We can actually put a 1206 resistor across the DALI bus, to give the lower load resistance (there is a not-fitted 1206 footprint there, which we intended either for a resistor or a...
  17. Closed: NPN is bahaving as oscillator when used with DALI comms bus

    Hi,
    We have a DALI communication setup. To be brief, DALI is basically square wave transmissions at 1200Hz.
    A DALI bus is pulled down and released at the 1200Hz frequency, as in the attached...
  18. Closed: Re: Isolated Dual interleaved PFC'd Flyback controller IC

    Thanks, will look into the FAN9611.........But with reference to the UCC28064A Dual interleaved PFC controller...

    We have just been looking into designing a Dual Interleaved Flyback PFC for VAC...
  19. Closed: Regulation via low power bias coil instead of opto's on the mains output.

    Hi,
    We have a contractor who has done away with our feedback optocouplers which were
    connected up with our main 26V, 50W rail,
    ....instead he has simply used a low power bias coil on the primary...
  20. Closed: Isolated Two transistor forward converter for Vin=220VDC, Vout=120W, 26V..sync rects

    Hello,
    We are doing an isolated 120W, 26Vout, Two Transistor Forward converter. Vin = the 220VDC output of a Boost PFC.

    I’ve always just used heatsunk diodes on the output in the past, but this...
  21. Closed: Isolated Dual interleaved PFC'd Flyback controller IC

    Hello,
    Do you know of an Dual interleaving controller IC for Isolated , PFC’d Flybacks? The load would be connected to the output of the dual PFC’d flybacks, which both pour their current into...
  22. Closed: Fault mode of synchronous recrifier IC with BCM flyback

    Hello
    We are using the LT8309 synchronous rectifier for a PFC’d flyback on 80-135VAC input…26vdc output. We are using it like in the attached LTspice schematic (which needs to be run with the...
  23. Closed: Re: 350V BJT cannot stand overvoltage of VCE=400V

    Thanks, so it will survive, but will be slightly damaged, and then when the overvoltage repeats again anfd again, the cumulative damage will build up and the device will fail?
    The 400V on VCE, is...
  24. Closed: Re: Please help clarify this doc on Earthing and EMC of Offline SMPS

    ...here's one at 200kHz
    https://en.wikipedia.org/wiki/Droitwich_Transmitting_Station

    - - - Updated - - -


    …Yes but common mode noise above 20MHz can occur in pulses, and those pulses can be...
  25. Closed: 350V BJT cannot stand overvoltage of VCE=400V

    Hi,

    The attached is a HV linear regulator based on a BSP19 BJT. This is rated 350V. At 100ms in the simulation, the VCE of BSP19 suffers a transient of 400V……our contractor says that because of...
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