Push Pull Converter

[arthurartmaster]

Hi all I wondered if anyone could please assist me with designing a push pull converter using LTC3721 IC from Linear technologies I have uploaded a LTSpice file that has the bare bones if anyone could please direct assist in how I can adapt this so the converter functions in the following manner:
Input: 12V
Output: +175V and -175V
Power Delivered: 300W.

Any help would be greatly appreciated. I am very foreign to this power topology so any help is appreciated.

Kind Regards

Art

 

[ronsimpson]

There are some problems with this circuit.
It is close. I fixed a number of the problems.

 

[arthurartmaster]

ok great thank you so much appreciate the assistance

 

[ronsimpson]

the assistance

Is this a school project?

 

[ronsimpson]

I don't have the stability worked out yet. This is a little better.

 

[arthurartmaster]

Hi I also started this design but I'm struggling a little to refine it the output voltages aren't quite what I need them to be if you wouldn't mind modifying it a little to get it working that would be so useful, I used parts from LTSpice libraries from:
With this one though I have a huge concern about the amount of current the switching FETs have to deal with from the transformer, I also noticed with the LTC3721 the currents are really high as well is there any way to get around this or I have to spec FETs that can deal with the currents

Thanks again

Art

 

[arthurartmaster]

Is this a school project?

Kind of I want to try designing a circuit based on the push pull topology that was covered recently I think trying to simulate and then design and create is a way a learn a lot more

 

[ronsimpson]

amount of current the switching FETs

Power Delivered: 300W

With a 12V supply the average current is 300/12=25 amps. The peak current is dependent on what type of power supply and the duty cycle. PK current = 30 to 50A.
If you right click on a MOSFET you can choose a different part. Watch voltage and Rdson.

 

[arthurartmaster]

With a 12V supply the average current is 300/12=25 amps. The peak current is dependent on what type of power supply and the duty cycle. PK current = 30 to 50A.
If you right click on a MOSFET you can choose a different part. Watch voltage and Rdson.

Ok is it worth invest using different FET is this were a lot of the losses are contained?

 

[arthurartmaster]

would you by any chance be able to modify the other LTSpice file I uploaded so the outputs are closer to +175V and -175V, also can you verify what the currents are like on the FETs in that file.

Thanks
Art

With a 12V supply the average current is 300/12=25 amps. The peak current is dependent on what type of power supply and the duty cycle. PK current = 30 to 50A.
If you right click on a MOSFET you can choose a different part. Watch voltage and Rdson.