multiple SMPS Voltages

[pol]

the output transistor generated the square wave.

---------- Post added at 06:57 ---------- Previous post was at 06:01 ----------

yes right,
the output transistor generated the square wave.

and next??

 

[muhammadali_16]

which terminology u r using ???? i mean Push-Pull, half bridge etc.....

 

[pol]

i use konverter dc-dc topologi flyback...
the problem is the trafo...

how to test the trafo that i had return,is well or not????
any one can help me?

---------- Post added at 03:36 ---------- Previous post was at 03:01 ----------

there is no one can help me???

 

[goldsmith]

Hi pol , test it with an oscilloscope and function generator , simply .

 

[pol]

how to test it i'm newbie with osciloscope and function generator...

 

[goldsmith]

Hi again Dear Pol
do you have access to the function generator and oscilloscope ?

 

[pol]

i think i didn't get the answer,

 

[muhammadali_16]

http://www.kpsec.freeuk.com/cro.htm


**broken link removed**

its better to study the above material first

 

[goldsmith]

Hi dear pol
Sorry if my sentence wasn't clear . if you have access to an oscilloscope and a function generator , you can do below things :
1- use a capacitor in parallel with your inductor . ( thus , you'll make tank circuit )
2- then give your sine wave signal from your function generator across your tank circuit ( don't forget to add a series resistor with your input .)
3- measure the voltage across your out put ( see my attachment , please ) with your oscilloscope . try to change the frequency of your function generator until you see the voltage is going down . when the voltage across your out put decreased by 3 db thus it means that frequency is your resonant frequency .
4- Follow this formula : Fr= 1/2*pi*((LC)under radical ) and you know the value of your capacitor and you know the value of your resonant frequency and you'll find the value of your inductor simply .
Note : if you use a large value capacitor the result will given faster ( you won't need to change your input frequency very high ). ( but remember , don't use electrolytic capacitors , or if you want use them , use two electrolytic capacitor in series bu back to back .


Good luck
Goldsmith

 

[muhammadali_16]

i want to know that how can i measure that damped fequency through osciloscope or any other alternative. give me a example so that i can understand it

Hi again
For snubbers , there are many ways , but i want tell you a simple way :
build your circuit without snubber and then see the overshoots ( oscillations ) and measure the frequency of those damped oscillations , and then use an RCD or RC network , the has an Fo=1/2*pi*R*C and F0 should be about the frequency of those oscillations and you can select the capacitor randomly and then you'll find the R , simply ( remember that R should have high wattage , but not very high , it require a bit higher wattage that you can calculate it simply .)
Best Wishes
Goldsmith

 

[goldsmith]

Dear Muhammad
Hi
See below , please :


Now i show you a wave form with zoom in .

So , what is the frequency of those damped oscillations ?
So i have designed an snubber network to improve those oscillations . see below , please :


Best Wishes
Goldsmith

 

[enjunear]

i want to know that how can i measure that damped fequency through osciloscope or any other alternative. give me a example so that i can understand it

Use a single-shot mode and capture an edge of your signal. Zoom in on the ringing on the rising or falling edge. Measure the distance (time) from peak-to-peak (count the grid spaces, and look at the oscilloscope's setting for the horizontal axis... time/division), do a little algebra (hint: freq = 1/period), and get the target freq. If you are using a digital oscilloscope just use the vertical marker functions... it should read out the Δt directly, and possibly the frequency, too.... which is just 1/Δt.

 

[muhammadali_16]

my input range is 24v(jeep battery) which varies from 22V to 36V. and i need output of 30V. im confuse that what terminology i can use becz of this wide range. im confuse when 30V input and 30V ouput, boost transformer become buck, is this fine or not

 

[goldsmith]

Hi again
You can use , each topology that can increase the voltage . e.g boost converter , you'll be able to stabilize your out put at your desired value with a simple feed back . ( at boost converter , vout = vin/1-D.C D.C= duty cycle )
Best Wishes
Goldsmith

 

[muhammadali_16]

so i can use SG3525 to this stuff or suggest me any of the PWM controller

 

[goldsmith]

Try to use a simple LM2577 it is boost driver , although you can use SG3526N but , if your input is battery , you'd better to avoid from using that IC , because of magnetic dissipation .
Best Wishes
Goldsmith

 

[pol]

i have did it,
i give input the function sine wave with 10 V peak to peak an give r = 1 kohm and c = 104 keramik capasitor.

but when i measure the output using osciloscop there is no the voltage,
i'm really confused.

 

[goldsmith]

Dear Pol
Hi again
Did you changed the frequency ?
if yes , from what range up to what range ?
Best Lucks
Goldsmith

 

[pol]

100 k hz, and the output generated its about 3 v

 

[goldsmith]

Hi again
100 KHZ , and out put 3 volt , is that out put of your filter ? how much is your input ? try to increase the frequency up tp 2MHZ.
Best Wishes
Goldsmith