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fredos 29th April 2006 02:40 AM

The news D-Amp DLS3000....
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Here some pick of our news prototype of the D-Amp DLS3000...It's a 1000W RMS per ch/4 ohms and 1500W RMS per ch/s ohms in class B-D, powered by a pair of STW50NB20 at +/- 92V by an IGBT heat sink less switching power supply. Full power measured for 15 min, 8 hours burn-in at 1/3 of maximum power. Sound is very nice. Some cue about the amp...Hight side of the drivers is powered by NE555 charge pump, 0-100% duty cycle, current sens only on the negative side, power limited in 2 ohms by an NSL32 optocoupler in the feedback loop, reduce distortion in 2 ohms and improve stability, first time I try this, and it sound very nice! Clipping limiter by JFET j112 into error amp, work very well and very fast too!

I will talk to you soon about news prototype of combinated amplifier and switching power supply in phase modulation, heat sink less for about 2 Kw per ch...seem to work well now, but some little thing to fix...

Have a nice views!

fredos 29th April 2006 02:42 AM

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fredos 29th April 2006 02:44 AM

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mgm2000ro 29th April 2006 02:32 PM

I'm not open another post again,please help me !
I find this schematic in a Sony project amplifier car class D ( XM-D1000P5 ).
I was trying to simulate this schematic in Orcad soft,but the rezultat is not good.
I don't find in my library KTC,KTA tranzistors ,but I simulate with another pnp and npn tranzistors.I don't find diod ISS226.
The rezultat of my simulate is good but the amplitudine of my output is just 10 mV. I can't up this amplitude indiferent of level of in.
This amplifier are supply power at +/- 90 V but the output power recomended by Sony is :
RMS: 500W/4
and maximus output :
The power of 900W/2 at a rail supply +/- 90V IT ISN'T TOO SMALL?
What eficience has this amplifier?

Best regards ,mgm2000ro!

fredos 29th April 2006 03:09 PM

I think you can maybe simulate with the 2N5401 and 2N5551 for the transistor. This look like a very low frequency PWM amplifier..Try to reduce the output capacitor, 100uF (the two 220uF in serie) will slow down a lot the switching frequency. For your diode, for sure use 1N4150, this is just a clipping diode for the error amp. If it dont work for the transistor, try the D45H and is complementary, this is fast hight voltage transistor. Anyway, I dont suggest you to go on that way, the mosfet drivers seem to work at hight power, so lot of dissipation in them...Try to modify it with a bootstraped version for the hight side, or at least with a IR2110...Have a nice day!


fredos 30th April 2006 01:43 PM

I just take a look closer to your schematics...Their was a mistake! Simply add a 100K-820K between the base of Q20 and ground to disable the mute circuit and everything should work weel!


Workhorse 30th April 2006 01:54 PM

Hi Fredos,

You primarly design your amp for 4 ohms rating and than derate their power rating for 2 ohms with the current limiter...Your Mosfet is having a low gate charge and its similar to IRFP260 except its gate charge is 234nC...

A very good have followed...

I have designed amp only for dedicated 2 ohms power level and recently used APT50M65B2LL Power mosfet to get 2KW at 2 ohms with Rails at +-110V Idle...
Also designed with IRFP260N ...1200W @ 2 Ohms .....

K a n w a r

fredos 30th April 2006 02:08 PM

Hello Workhorse

It was in B-D? What I mean is that their is no carrier, or just some pulse some time at the input of the output filter? Only positive pulse when positive signal and negative pulse with negative signal? It was full range? Why did you need +/- 110V for 2 Kw 2 ohms? You should get nears 3 Kw of power! Have you try the 300V version of APT? They have lot lower RDSon! I will try as soon as Y received my 300V mosfet to push it a little more, the only power dissipation I have so far is in the bridge rectifier of the power supply...Have you try a ESD1 diode in parralel of power mosfet? This help a lot for the recovery if you are in class B-D!

Have a nice day!


Eva 30th April 2006 02:12 PM

That will be a nice RF transmitter considering the rated 330ns reverse recovery time and 21A reverse recovery current at 100A/us for those STB50NB20 MOSFETs. Current spikes in excess of 50A rising at 500A/us are guaranteed with such an output stage. These MOSFETs are not suitable at all for classic class D topologies, there are special devices with faster body diodes for these duties but that is achieved at the expense of higher Rds-on.

Also, what do you exactly call class B-D? The pictures show a bare two-switches-and-a-LC-filter output stage, the one that almost everybody uses.

And last but not least, are those common-mode filters of the SMPS really wound on the classic yellow-white coloured iron powder cores??? :whazzat: They are not going to filter anything that way :D

Workhorse 30th April 2006 02:16 PM

Hi Fredos,

Mine design was just a simple half bridge type not a full bridge in BD mode...
The carrier Frequency was 250KHZ...
For 2KW in 2 ohms 110V rails were needed....
Yes I have Tried APT30M85BVR....also Nice results....

I put the Schottky diodes in series with Mosfets and connect an anti parallel diode to that combination to deal with freewheeling current and also it helps alot in case of short circuit also....

K a n w a r

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