ir2110 and 6 x irf640 per side?

[jake83]

Hi

I have been wondering if it is possible to use ir2110 gate driver to drive directly six irf640 per side @ 50 kHz? This would be a subwoofer amp...

What would be suitable duty cycle? 95%-5%?

Thanks.

 

[mgm2000ro]

http://img443.imageshack.us/img443/8749/cumaimultitranzistoriqd1.jpg

 

[zilog]

I have scanned three pages from Pressman's book, where rise and fall time for different mosfets and differing gate drive currents is shown. Dont forget that you will need substantial current sinking capability to keep the low side mosfets from turning on through the miller capacitance when the output swings from low to high, and vice versa.

http://wintermute.csbnet.se/~zilog/presman1.jpg
http://wintermute.csbnet.se/~zilog/presman2.jpg
http://wintermute.csbnet.se/~zilog/presman3.jpg

 

[jake83]

Thanks for answers

I have been thinking about buffering ir2110 outputs...

Is bipolar complementary pair most commonly used?

How about using mosfets to buffering? I haven't found any examples of this. Should there be high Vgs voltage also in these buffer mosfets (I believe so).

 

[jake83]

As for using bipolars, I have been thinking to use BD243/BD244...

 

[sixtek]

No need for these medium power BD243/244 devices...
BC327/337 or BC639/640 will do the job!

 

[zilog]

Just make sure the BJTs have high enough hfe at the Ic you want to drive your mosfets with, smaller BJTs often fail at this.

 

[jake83]

No need for these medium power BD243/244 devices...
BC327/337 or BC639/640 will do the job!

What do you think, how high gate charge load are these devices able to drive for example @ 50 kHz ?

 

[sixtek]

At 50kHz IRF640 needs max. 3mA gate drive current.