Spice IV simulation does not match the actual circuit.

[Centripetal]

Hello everybody, I’m trying to solve a SPICE issue with the vanilla2 help, but pasting a schematic is required. How do I paste a draft here, since I’m not getting it for  the page shows an error message.

[ysadmin]

Hi dercides,

below the text panel you can find the button “Attach a file”.What kind of files are you trying to upload? for jpg, png .zip .rar you shouldn’t have problems if they are not very large.Let me know if you still have problems and the exact message you get.
cheers

[Centripetal]

     Hi again,

    It’s a 60,4k PNG file.

    

    The message error is:

     File upload failed, reason:

     (Draft 4 (2) .PNG internal error, could not move the file.

[ysadmin]

Try again, please

[Centripetal]

     My main and only goal here at this
time is to clarify a technical dilemma ( LTSpice IV x actual circuit)
occurred during the implementation of a simple circuit in which the
results from LTSpice and actual circuit were significantly different
and I would like to know what could be wrong so that I can
effectively put into practice what is actually being simulated by
Spice.

As mentioned before, it is a
very simple circuit in which C6 charges up through L1 and is
discharged through L2. The problem is that the charging time in C6 is
60 uS Spice simulator (The time that I need ) and about 15 uS in
actual circuit. So the problema is either Spice or is the circuit.
Which one is right or wrong ?. I’m sure this question will be solved
here.

Thanks.

                                                                                                                                                      (Sorry for English … I try to improve …)  

[swathi vasamsetty]

Hi, the 555 output and the input to the Q1 in the real circuit is equal to the simulation?, Ton=58us Toff=4us.can you measure it?
It seems as if the diode D2 is shorted.

[Centripetal]

Hi Maurone,

Yes, it was measured with a HITACH
Oscilloscope V-212 20MHz.

D2-R2 is the M1 tON control and
D1-R1 is the M1 tOFF control as well.

[swathi vasamsetty]

If all the components work fine I could think to a saturation of the inductor,
but the current is small. very weird.
In the real circuit the period of L1 current is 60u and the voltage charging period of capacitor (blue line in simulation) is 15u, right?
try to exclude the transformer?, the reflected impedance should be about 1,4 Ohm.

[Centripetal]

   

[Centripetal]

   In the real circuit the period of L1 current is 30 uS and the voltage charging period of C6 is 15 uS.

   I excluded the transformer but nothing
changed. The transformer does not affect the
charging time of C6, as it is blocked by D6.

[Centripetal]

     Correcting my previous post, 
the voltage charging period  of C6 is also 30 uS,to be more accurate, both with 26 uS…

[swathi vasamsetty]

this is the simplified model of your circuit. I used other diodes but this doesn’t affect the result.
As well as the mosfet M1 approximates the behavior of an ideal switch there is no
reason because the period of L1 current and charging voltage period of capacitor are mismatched.If Ton=4us and Toff=58, they must be equal to about 60us.If L1 current period is 30u and charging voltage period is 26us is ok, but Ton=4us and Toff must be 26u.Try replacing M1 with a new one, or with another switching mosfet.

[Author]

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