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Old 18th July 2005, 08:01 PM   #1
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Exclamation Class D amplifier 1 KW RMS

hi friends.... I am inexperienced in this forum, I want to develop an class D amplifier with 1KW rms.... yours can help me?


Elias Novaes:
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Old 19th July 2005, 03:00 AM   #2
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I suspect it would be easier to buy one of these:
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Old 19th July 2005, 06:34 AM   #3
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If you've never designed a class D amplifier before, start at a discrete 25W circuit and see if you can sort out all control / EMI / reliability related design issues. Next, move up a station to 100W. This will bring up a fresh set of problems. The next step can be 1000W, and, if your even mildly critical about switching behaviour, this will show you every corner of MOSFET physics you can dream of.
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Old 19th July 2005, 10:32 AM   #4
Antz is offline Antz  United Kingdom
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Default Class T Option

You may consider building a Class T amplifier. It also has a switching output topology but the creation of the switching signal follows a digital route. Tripath,, make the necessary processing chips all you have to do is add the output FETs. Again it is a very power efficient design which results in low weight but high power. There was a 300W per channel, bridge-able to 600W, described in Elektor Magazine starting June 2004 based on Tripath's TA3020. If you would like the articles I have them in soft format, I can email them to you.
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Old 19th July 2005, 12:11 PM   #5
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Elias: Is your design intended for full range Hifi or PA, or only subwoofer?

And in what impedance are you going for 1 kW? 8 Ohms 4 Ohms 2 Ohms?

Best regards from

Lars Clausen
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Old 19th July 2005, 12:56 PM   #6
mzzj is offline mzzj  Finland
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And I am on my wa to explode 4kW class-D subwoofer amp
har har
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Old 19th July 2005, 01:08 PM   #7
skaara is offline skaara  Slovenia
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Im also thinking of class d amp (1kW and up) for frequencies up to 500hz-1khz for some time now, i would like it to be as simple as it could be, quality is not an issue because i would use it for PA..

With which pwm modulators could i achieve this?

Would it need nfb (i dont care for the distortion so much as for loudness, i think i could get away with distortions up to 1-3%.. what do you guys think?) ?

If anyone has some ideas (or schematics..) which would help me start this project i would be very grateful

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Old 19th July 2005, 01:58 PM   #8
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Skaara: If you only need up to 1 kHz, you can get away with quite a lot of dead time, making the output stage simple, and the efficiency high.

If you are talking 8 Ohm 1kW you need a rail voltage of around 135 V DC. This means you are looking at 400V MOSFET's.

The peak current is 16 Ampere @ 8 Ohms, 32 Ampere at 4 Ohms etc. You can get very powerful 400 - 500 V MOSFET's in a small package. One of the best one in TO220 package is STP20NM50 from ST. A pair of these could be made to produce 1kW in 8 Ohms, if cooled properly. I have run them up to 400 kHz with 150 V rails with no problems.

If you want to cover 2kW in 4 Ohms, you have to look at IXYS or APT. They are in a whole other ballgame of power!
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Old 19th July 2005, 03:36 PM   #9
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AMP2 from would be close?

Voltage DC*1 VA rating*2 Speaker impedance Output Comment
+/-45V 750 4 ohm 2x300W Standard solution
+/-45V 400 8 ohm 2x150W Standard solution
+/-45V 750 8 ohm bridged 1x600W Standard solution
+/-60V 750 8 ohm 2x300W Standard solution*3
+/-60V 1500 4 ohm 2x600W Requires component upgrading*4
+/-60V 1500 8 ohm bridged 1x1200W Requires component upgrading*4
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Old 19th July 2005, 04:38 PM   #10
SSassen is offline SSassen  Netherlands
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Did I post my 4KW full-range, audiophile class-D amp schematic yet, with zero-dead time and 99.99% efficiency? No? Well, that's because I would have a hard time designing it in the first place, as Bruno correctly pointed out.

What I am wondering about though is what's with these people that seem to think designing and building a class-D amp is like ordering a LM3886 and soldering a few parts to its leads to make it work?

Or am I missing the point here?

Sander Sassen
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