how much power can i get fro IRFZ44?

[Astro Power]

i want to build this :

http://sound.westhost.com/project89.htm

power supply...

i have total of 12 IRFZ44..... how much power thay can give me?

tamir

[arcom]

A wild guess would be around 2-2,5 kW with adequate cooling & transformer.

[N-Channel]

If you know the Rds (on) of the 'Z44, and the voltage you're working with (in this case, a nominal 12-14V), then you can get a pretty good idea.

If, say, the 'Z44's Rds (on) is 0.026 ohms (just a guess- check the datasheets), and at 12V, you're drawing 20A, then the power dissipated by the MOSFETs will be I^2 x R.

For this example, take 20A, square it, and multiply the product by the R ds (on) of the MOSFET. 20 x 20 x .026 = 10.4W Dissipated, per MOSFET.

If you're going for power supply efficiency, try paralleling the MOSFETs, and the power dissipated by them will be cut in half.

[Astro Power]

http://www.remcomplekt.ru/datasheet/trz/IRFZ44.PDF

the datasheet of the z44:

R(ds) = 0.024 ohm
A = 50A
Power Dissipation = 126W

that is mean


in 14V the z44 can out maximum of (126\14=31.5A)

so... (31.5*31.5)*0.024 = 23.8W

126-23.8=102.2(W)/14(V)=25.5A

so 6 of z44 can give me 6*25.5 = 153A*14V = 2142W = 6 of Z44


like that ?

tamir.

[EnvisionAudio]

Only in best case circumstances. In the real world, you must derate the component according to environmental and electrical effects. You have junction temperature, thermal resistance and intertia and the SOA of the FET. All of these (and many more) must be considered when designing maximum current capability. Is this going in an automobile? Isn't the heatsink going to be hot in the warmer months? Another derating.

In my experience, 12 IRFZ44N (6 per phase) will handle ~60A continuous in the configuration you state with a switching frequency of 50kHz and "normal" vehicle electrical anamolies (load dumps, etc).

[Eva]

Analyzing only conduction losses in switching circuits is like telling only half the story

There are also switching losses, and sometimes there are also additional losses due to avalanche effect caused by unclamped transformer leakage inductance

Switching losses are strongly dependent on gate drive and rise/fall times, the faster the switching the lower the losses but the higher the EMI radiation and the higher the likelihood to excite RF resonances between PCB tracks and components further increasing EMI

In other words, the power output obtainable from a set of MOSFETs is also dependent on transformer design, layout and gate drive

Are you going to use regulated or unregulated output topology? The analysys is quite different

[gearheaddruid]

Hi, My experience with these mosfets, you should be good for about 650 to 700 watts with the right transformer. If you need cores and/or Litz wire, email me and I can fix you up. Regards, Steve

[Astro Power]

ok........ i will photograph the car amplifier powersupply....

my next question is........

i learn yesterday how to to twist around transformer... of car amplifier...


13.8V = 4 turns.... if i want in the out 45V i will calculate like that:

45\13.8=3.2

3.2x4= 12.8 so i will need to turn 13 turns to get 45V

(of course i need to turn double to get 45V +\-)

now i want to know how amper will out the wire that i twist around with him the transformer....

because i want 45V +\- with 20A.

soo how much diameter the wire(s) need to be?

thanks tamir

[Astro Power]

some photos....:

2MB BIG PHOTOS !!

http://www.mamsh.com/111.jpg

http://www.mamsh.com/112.jpg

http://www.mamsh.com/113.jpg

http://www.mamsh.com/114.jpg

i want to build more powerful power supply

to get more power on 1 ohm subwoofer......

tamir

[gearheaddruid]

Astro, is that the power supply from a Pyramid? Looks like you have plenty of room for a big supply. Look up in the trading post area for my listing of LITZ wire. There is an explination of why you should use it. It will be much easier to wind the transformer. Your secondary winding should be at least #12 wire if you are using it as a sub woofer amp. I would recommend #10. The primary is going to require a lot of conductor. I would say, double up the big Litz wire (105 strands of #30) for each leg of the primary.

When you start to drive the amp bridged, I would heatsink the drivers that are hanging on the perfboard. They are going to get hot!

What part of Israel do you live in? My wife has family in Kfar Saba. Regards, Steve