I could never get 2092 to work on its own with irfb4227's.
It was fine at low volume but on high power it would going into reset mode.
I had to use 4420's or a totem pole gate driver to get it to work to full power.
Hi i just put the oscilloscope on the output and look at the carrier wave and workout from the timebase. Greg
Like I said, totem pole lacks base resistor towards irs2092, this is probably the cause of excessive heating of irs2092
What was dead-time set ?
the boards finally arrived. we modified one with irfb4227's. the amp came up fine with a 4Ω load. when we pushed the input to 100mv, the amp fried the H669A trasistor and set the speaker ablaze... is there another nod or transistor we should use? thanks
BC639 and BC640 ?!
Ther is problem with 2 elcos at Vcc and Vb pins, they are very hot, they should be replaced with 25uF 25V cheramic, tantal, (maybe low esr elco would work) ..
I put 10 ohm in series with IRS2092 between totem pole gate driver, now irs2092 is not that hot.
LD30 PERFOMANCE - HEATING
I have abandoned this type of amplifier. I found a more suitable solution for my needs. Hopefully, someone has had better success and will reply to you. good luck, going forward. -hjp
I have abandoned this type of amplifier. I found a more suitable solution for my needs. Hopefully, someone has had better success and will reply to you. good luck, going forward. -hjp
Ordered two of these after reading ljm's vote of confidence. Good news is they worked right out of the box. Clean output (relatively) and a lot of output.
It did run hot, turning the 2.2k resistor brown, then poof... 78vdc to the speakers, blowing them before the fuse went out.
The second one ran for 7-8 minutes then same thing dc to the speakers... this time I was quick enough to pull the plug... this time 61vdc on outputs...
Boards malfunctioned within minutes....
load was 8 ohms, rails were +/-80vdc. I had 10,000uF on each rail
All components were too hot to touch after 8-10 minutes, including the OP inductor. Not sure what component blew... I am not good with either mosfets or class D amps... should have stuck with bjt's..
waste of time...
It did run hot, turning the 2.2k resistor brown, then poof... 78vdc to the speakers, blowing them before the fuse went out.
The second one ran for 7-8 minutes then same thing dc to the speakers... this time I was quick enough to pull the plug... this time 61vdc on outputs...
Boards malfunctioned within minutes....
load was 8 ohms, rails were +/-80vdc. I had 10,000uF on each rail
All components were too hot to touch after 8-10 minutes, including the OP inductor. Not sure what component blew... I am not good with either mosfets or class D amps... should have stuck with bjt's..
waste of time...
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You should have noticed sooner that the guy called "ljm" disappeared from this thread as soon as problems started to be reported, and that was 1+ years ago, and he was probably just looking for easy money+experience by making an ignorant copy of some IRAUDAMP and selling some dozens. No measurements or oscilloscope plots posted.
Reasonable reliability can only be expected from fully IC based class-D stuff available at ebay. Amplifiers for +50V single rail are the biggest fully IC based ones, I think.
On the other hand, you should have stopped and asked when you noticed the modules were overheating when idle.
On the other hand, these modules are so simple that repairing is a matter of getting some IRS2092S, some IRFB4227, some NPN/PNP gate buffer BJTs and diones, and some SMD resistors. These circuits are supposed to be sold for class D educative purpsoes.
If you want a class-D reference design you will have to get something else, these modules are not representative haha
Reasonable reliability can only be expected from fully IC based class-D stuff available at ebay. Amplifiers for +50V single rail are the biggest fully IC based ones, I think.
On the other hand, you should have stopped and asked when you noticed the modules were overheating when idle.
On the other hand, these modules are so simple that repairing is a matter of getting some IRS2092S, some IRFB4227, some NPN/PNP gate buffer BJTs and diones, and some SMD resistors. These circuits are supposed to be sold for class D educative purpsoes.
If you want a class-D reference design you will have to get something else, these modules are not representative haha
It could be they were made using inferior or fake mosfets.
I bought some IRFB4227's off ebay and they popped very easily.
Got some from RS Components and they were fine.
The irs2092 is very fussy about layout and decoupling.
It also doesn't have the best of gate drivers. With IRFB4227's I found I needed discrete gate drivers on the output of the 2092.
If you are going to fix them then beware that often the mosfets failing will take out the 2092 too.
I bought some IRFB4227's off ebay and they popped very easily.
Got some from RS Components and they were fine.
The irs2092 is very fussy about layout and decoupling.
It also doesn't have the best of gate drivers. With IRFB4227's I found I needed discrete gate drivers on the output of the 2092.
If you are going to fix them then beware that often the mosfets failing will take out the 2092 too.
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Thanks Eva and Nigel
Nigel I read in one of your other posts about hooking a scope on to these boards. I had an old scope connected to the output via a 30 ohm resistance to ground of the scope. I was trying to see clipping point of the smp at +/- 80vdc rails. Mine clipped at close to 52 vac rms into 4 ohms.
Could the scope have caused the issue?
Nigel I read in one of your other posts about hooking a scope on to these boards. I had an old scope connected to the output via a 30 ohm resistance to ground of the scope. I was trying to see clipping point of the smp at +/- 80vdc rails. Mine clipped at close to 52 vac rms into 4 ohms.
Could the scope have caused the issue?