Direct drive in full-bridge topology

[Disney_SK]

How do you drive the switching transistors in this case?
Because as far as I know, transistors are driven by base-emitter (gate-source) voltage and emitter (source) voltages are different for each couple of transistors, so how do you connect ic driver (buffer) to them?

 

[Danko]

Hello!


One of my friend connected the mosfet drivers, and the fets like this: http://sziget.mine.nu/~danko/aramkor/smps/car-smps/12V1000W.ps

Have fun!

--
Danko

 

[Disney_SK]

Thanks for the reply, but I am afraid I can not open the file... is it an image file?

 

[Pierre]

You cannot open it with the browser because it is a postcript file. Danko, could you translate it to pdf for us, please?

About your question, Disney_sk, you have two options: use a transformer coupled gate drive or two high-voltage driver ICs (IR211X from International Rectifier).

Best regards,
Pierre.

 

[Danko]

Here's a part of that PostScript file:

http://sziget.mine.nu/~danko/aramkor/smps/car-smps/gate_driving.jpg

Unfortunatelly, my friend, who draw it, he draw it into a huge size, it doesn't fit in 1:1 view on my 19" monitor

btw, typing into g00gle the "ghostview download" gives you plenty of PostScript viewer programs.
Under Debian GNU/Linux you just have to type in "apt-get install gv"

P.S.: I haven't checked the schematic.... But my friend works at here: www.pknc.com
He's the electronics-designer.
--
Danko, the linuxuser

 

[Jaka Racman]

Hi,

I think you will get more information from IR2110 datasheet and Application note AN987a.

Best regards,

Jaka Racman

 

[Disney_SK]

Thank you all for your replies. In fact, I did not know that IR2110 contains an optocoupler... But now I can see very clearly how it works. I do not want to use transformer drive in my next project, I want to try direct drive, as the guy from d-amp.com recommends... but currently I am out of money

 

[N-Channel]

IR2110

Dis-

The IR2110 does not use an optocoupler (they're way too slow). it uses level-shifting for the High-voltage floating supply. Just wanted to clear that up.

Steve

 

[mflorin]

Hi all,

My suggestion is to use gate drive transformers. I play a little bit with IR's and I blow up a few(about 20). There are many aspects that you have to consider if IR's drivers are to be used.

First of all the IR's drivers don't assure galvanic insulation.The high side channel is build in a so called "isolated silicon tube".One of the most important thing is the PCB layout.Take care of undershooting.

Because of the layout I had to many incidents and finally I "fixed up"a few PWM controllers and an ATMega8.

After two months I could make a good PCB for an inverter that works fine with IR's, but was two expensive months of trial and errors.

So, if you have some "extra money" you could try to build your bridge but be aware of pcb.Use ground plane.Helps a lot.

Sorry for my english.

Regards,

Florin