YJ-IRAUD 350

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Hi DIYers
I paid a module YJ-IRAUD350 € 38 on Aliexpress and I was immediately pleased with his good sound. I have a big problem, in spite of the power supplied, the operation time, the impedance of the speaker, the power supply voltage, the resistors R6 and R7 adapted for the voltage of 45-0-45 "AC" by 3.9KOhm to 4.7 KOhm, the amplifier goes into protection mode ... and after a few seconds starts to work and this thing becomes cyclical.
These are the conditions of operation:
- Toroidal Transformer 45-0-45 AC - 1000 VA;
- Impedance speakers used: 4 Ohm / 16 Ohm.
- Input: iPod / Computer / Esoteric Analogic Preamplifier / Guitar Tube Preamplifier etc. etc.

The heat sink is hot (50 ° C) if the volume is high but is lukewarm if the volume is low. I do not know what to do ... Help please. Thanks to all those who will answer

Ing. Giuseppe Clemente
 

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Jacob thanks for your answer.
Yours is good advice, but I do not know if I can implement it because I use a toroidal transformer with secondary 45-0-45 ... therefore I have a DC voltage of 45 x 1:41 = 63.5 Volt.
You advise me to change also the mosfet?
You think that I'm using the MOSFET is defective?

thanks for your patience :)
 
chienmort Thank's for your reply
... mmmmmmmm in these conditions I don't know what mosfet to use...
Now I try on data sheet....

This anomalous behavior, the amplifier will block, is a behavior that I found on all amplifiers in class D. I bought, for the game, a 10-watt stereo amplifier, Class D, I plugged my speakers , Martin Logan Aerius, and listening is great but if I exaggerate with the volume, stop all, I have to turn off and turn it back on. The source is a sound card Metric Halo ULN-8.

It is possible that this is an undesirable feature of all the systems in class D?
 
Over voltage protection is protecting the MOSFETS from operating outside their maximum ratings, voltage, currant or temperature. All these parameters are interrelated and are set by the IRS2092 controller. Most Class D designs will incorporate some or all of these protections.

Protection circuits make a discrete design very complex and can often cause as many problems as they solve. Most class A/B Amos they have short circuit protection, a crude form iof over current protection but no over voltage protection.

I am no expert on MOSFETS but there is a chart on the IR website showing clearly what MOSFETS are good for what voltage/power/impedances. Unfortunately I cannot find it at the moment.
 
The 2092 is detecting an over current event and is resetting itself for a few seconds.
I don't know what mosfets you have in there but if they 4019's they wont drive 4 ohm loads.
If you want to drive 4 ohm loads then you need better mosfet. The trouble is more powerful mosfets tend to have higher capacitance which will upset over current detect again.
I would try it with 8 ohm speaker and see how you get on.
 
the infineon IPP320N20N3GXKSA1 is a much better choice, 3xlower rdson,still lower gatecharge and reverse capacitance than the fets normally sold with this aliexpress device. I changed the relay into a 48V device to save power in de series resistors.
the change to 4.7K may not be needed, it is advised for voltages above 50V AC. 3.9K for 40- 45Vac. you may run short on the local rails otherwise
 
The fets that came with my IRAUD550 were IRFB23N20D: 100milliohms, Qtot 57nC, mostly due to the large feedback capacitance of this outdated FET (2004).
the infineon IPP320N20 (2011) has 22nC, and a resistance of 32milliohms. the heatsink between the caps on top of the irs2092 is the result of the large charge it needs to drive. it will run cool with the infineons.
also the 63 V supply makes that the IRS2092 needs to work harder because of the large drain gate charge of the IRFB23N20
I just need to check the deadtime as the lower output capacitance of the IPP gives a faster switching , also due to the lower gate charge drive requirements.
the current deadtime is 45nSec (10k,10k) and that may be OK for the infineon but maybe too small for the slower IRFB32N20 fets, maybe also why they heat up so easy.
did you check the oscillation freqeuncy ( near 350khz)
 
the infineon change has a lot more implications. the dead time needs to be set to 25ns. the overcurrent thresholds need to be adapted to the much lower RDson.

on top of that the elcheapo output inductor heats up (100degrC at 400khz) due to the much faster rise time, So i'm winding a powder toroid. also the inductor seems to saturate on the temperature and medium power, then the dc detect (uPD1237)switches the relay off. all in all the infineon change may not be such a good choice...
 
it turns out all the idle power goes into the output inductor, as this one has to push quite some current back and forth especially at +/- 65V. tried various mixed of powder, but T200-2 gives the lowest idle power and virtually no heating of the output inductor. A bit large though. I will try the sagami or ICE parts, hope they do better than the chino's
 
I also ordered the new gapped ferrites from ferroxcube TN26/11-3C20-A113
I found them at contrans.pl (info@contrans.pl) the website will be in english soon, but google translate helpedme through the shopping process. the ferroxcube app note claims lower open loop distortion than the T106-2.
 
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