Wanna know about smps design

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
I don't want to sound silly, but that waveform looks really polluted with EMI. You have still a lot of work to do to clean things up. The amount of rubbish during switching transients (both unexpectedly picked up by oscilloscope probe and present where you are measuring) has to be reduced by at least an order of magnitude.
 
Re: Good reference

rt7085 said:
You are asking very fundamental questions here! So, instead of explaining every detail I am going to recommened a book to you: "Switching Power Supply Design & Optimization ", by Sanjaya Maniktala.


Sanjaya has a new book out: "Switching Power Supplies A to Z" --and I believe that there is a webcast he did which is archived on National Semi's website.

Jack
 
dear jack,
right now i dont have access to the book, so please help with any suggestions what should i check.

Actually i have used ultra fast clamping diodes on source drain of mosfets, but did not use any snubber, should i use it, how do i calculate the cap res values.
 
OK, now i get a perfect gate pulse, and now there is no heating on the mosfets too.
I added a Fan as a load & everything gets smooth, & did not attach a snubber.
 

Attachments

  • op volt new.jpg
    op volt new.jpg
    19.1 KB · Views: 238
Please Please reply GURUS,

I have a 15V tap on trafo, i wanna know what value of startup resistace from +320V to positive voltage for the circuit, so that it should be able to startup the circuit and be capable of initial full turn on of the Mosfets properly. Presently i am giving reg 12V from seperate transformer to the circuit.

One more thing is, when i attach the 12V 21W bulb to output, the input DC shows 290V, when AC is 230V, is that OK. Cause I have designed Trafo for 360 V input.
 
I have just started making a Full Bridge 800W SMPS for audio amps application.

Previously i have made 150W 12V to +_35V Car SMPS which is working fine since last 3- 4months.

1. I wanna know what is the power handling of Siemens EE55 & EE65 cores.

2. As per the circuit given input would be 360V and output +_35V 15A, what should be the min value of input filter Capacitor.

3. I am gonna use 25Khz Swithching Freq using 3525 & i will use 2110 for driving mosfets, Duty Cycle would be 49%, is there any need of filter Choke on output.

4. Selecting Mosfets ??? for 800W.

5. Mosfet voltage 600V .OR. 500V would suffice.

6. Mosfet driver 2110 .OR. 2113



---- EE65 wont handel more than 2.5KW continuos load and may be 4KW peaks at 125KHZ , as per design company recommends. it wont handle the HEAT, UNLESS proper cooling system is there, This is what I can say.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.