IRFP4227 -> +/-100 V max!
6000W & 100 V peak: 0.8 ohm load impedance.
I would say: two of this in bridge are needed for real 6000 W (@ 2 ohms).
6000W & 100 V peak: 0.8 ohm load impedance.
I would say: two of this in bridge are needed for real 6000 W (@ 2 ohms).
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Joined 2002
200V rail's hope there is some serious protection in that amplifier, wouldn't want to see the SMOKE show it provided after it blows up 🙂
The mosfet driver totem pole BJTs are rated 80V so the
supply must be below +/- 80V.
Assuming the supply is 80V the maximum output power is 1600W on 2ohms
or 800W on 4ohm
supply must be below +/- 80V.
Assuming the supply is 80V the maximum output power is 1600W on 2ohms
or 800W on 4ohm
No bias at all ensures no cross-conduction. Note that these transistors are driven with a square wave, a logic signal, not with an audio signal, and that bipolar transistors tend to exhibit longer turn-off than turn-on delays. Note also that conventional bias schemes only work well at audio frequencies, not for the ~100ns current transients that these buffers have to deal with.
And here is a photo of the results of the first testing done on the 6kw power amp at IR's development plant....
5KW at 2 ohms (20 msec) are achievable with a full bridge of IRFB4227 pairs, IR2113 with buffers, a tight layout and a good active current limiting system. I have done that.
Testing at these power levels is difficult, supply voltage sags and available power is quickly reduced to 4KW or less after 1 sec.
Note that this is neither a project for unexperienced people nor something that you can just build from a schematic.
Testing at these power levels is difficult, supply voltage sags and available power is quickly reduced to 4KW or less after 1 sec.
Note that this is neither a project for unexperienced people nor something that you can just build from a schematic.
Eva, what are the limiting factor(s) when targeting max output with the half bridge implementation? I'm not only referring to this design. Let's assume there's an appropriate buffer between the IRS2092 and MOSFET gates, the MOSFET are matched, inductor is optimal, appropriate power supply, and load = 4 ohms. I'm guessing switching losses will be very high but maybe it can work by reducing the switching frequency?
Sorry, I meant "200V MOSFET"
200V blocking capability limits maximum practical half bridge rails to +/-90V or so, which translate into (90*.707)^2/2=2kw @ 2 ohm
Full bridge doubles output swing resulting in (180*.707)^2/2=8kw @ 2 ohm
Full bridge also allows to use a supply voltage closer to 200V because there is no pumping.
200V blocking capability limits maximum practical half bridge rails to +/-90V or so, which translate into (90*.707)^2/2=2kw @ 2 ohm
Full bridge doubles output swing resulting in (180*.707)^2/2=8kw @ 2 ohm
Full bridge also allows to use a supply voltage closer to 200V because there is no pumping.
+/-120V rails only give 3.6kw on 2 ohms, not much improvement considering that Rds-on is doubled and reverse recovery charge of body diode is doubled too (from 200V IRFB4227 to 250V IRFB4229).
Note that these figures are very optimistic. There will be a lot of sagging unless the power supply is regulated (which increases complexity, size and part count), resulting in substantially less power. Not to mention that regulating a single rail supply for full bridge is much simpler...
Note that these figures are very optimistic. There will be a lot of sagging unless the power supply is regulated (which increases complexity, size and part count), resulting in substantially less power. Not to mention that regulating a single rail supply for full bridge is much simpler...
But you'll sure as heck get the 6000W at 2 ohms with a full bridge from +/-120. Even if it sags to +/-85 under load. Most real amplifiers do this.
As far as the higher Rds and Qrr of the higher voltage part, it seems you have two choices. Either put up with higher switching and/or conduction losses or put up with it being fragile. Pick your poison🙂. The same goes for any amplifier, really - high fT Jap outputs don't have the Is/b of the old hometaxials.
As far as the higher Rds and Qrr of the higher voltage part, it seems you have two choices. Either put up with higher switching and/or conduction losses or put up with it being fragile. Pick your poison🙂. The same goes for any amplifier, really - high fT Jap outputs don't have the Is/b of the old hometaxials.