Hi
I have a big problem with the IRS2092 Amp from International Rectifier and the MOSFET "IRFB4227" .
The Amplifier works well ... when it works ...
It does not start up!
On the one hand when I drive the high input (U_eff ~3V) with no load then it starts up and works correctly. On the other hand when the class-d amp drives a load I need only to touch the input and the amplifier is going to work correctly.
Can you give me an advice what I am doing wrong???
In the attachment I enclosed our class-d schematic and some snapshots from the scope (scope on IRS2092 PIN13).
I have a big problem with the IRS2092 Amp from International Rectifier and the MOSFET "IRFB4227" .
The Amplifier works well ... when it works ...
It does not start up!
On the one hand when I drive the high input (U_eff ~3V) with no load then it starts up and works correctly. On the other hand when the class-d amp drives a load I need only to touch the input and the amplifier is going to work correctly.
Can you give me an advice what I am doing wrong???
In the attachment I enclosed our class-d schematic and some snapshots from the scope (scope on IRS2092 PIN13).
Hi,
thank you very mutch for this tip .. now the amp works perfectly!
But now I have a new problem ... ich have create a second amp. This amp like realy the same as my first amp ... the same PCB layou and the same components. But the output signal is different and whem I power it on it dosen't start
The porotection comes every ~0,5 sec and the amp makes a restart.
The amp starts wenn I gave in a big signal <-- like the first amp.
Can it be that the DT is too small or the protection is too sesitiv?
thank you very mutch for this tip .. now the amp works perfectly!
But now I have a new problem ... ich have create a second amp. This amp like realy the same as my first amp ... the same PCB layou and the same components. But the output signal is different and whem I power it on it dosen't start
The porotection comes every ~0,5 sec and the amp makes a restart.
The amp starts wenn I gave in a big signal <-- like the first amp.
Can it be that the DT is too small or the protection is too sesitiv?
tantal.lpt said:Hi,
thank you very mutch for this tip .. now the amp works perfectly!
But now I have a new problem ... ich have create a second amp. This amp like realy the same as my first amp ... the same PCB layou and the same components. But the output signal is different and whem I power it on it dosen't start
The porotection comes every ~0,5 sec and the amp makes a restart.
The amp starts wenn I gave in a big signal <-- like the first amp.
Can it be that the DT is too small or the protection is too sesitiv?
Probably I can't help you more, but useful information for others (experts) may be what's the difference between this and the other amp?
Hi,
I had the same problem with IRS2092+IRFB4227.
When I was pushing the amp the current limit trips in and mutes the amp for around 0.5s.
Check the voltage on the IRS2092 pin 5 (CSD). If you find it going down to -5V (the VSS rail) when it mutes it means that the current limit trips in.
Current limit thresholds are set trough resitors. Check on the IRS20955 datasheet (there is no information on the IRS2092 datasheet...) how to set these thresholds.
If you have a too inductive path between the low side mosfet source and the COM terminal (pin 10) of the IRS2092 the current limit can trip due to voltage spikes, muting the amp far before the calculated current limit. (I have the same problem on my design).
My amp works fine with 5k6+4k7 for dead time (40nS). If it is not enough increase it to 65ns by putting 8k2+3k3.
Why did you put diodes in parallel with the gate resistors?
By doing this you will change the behaviour of the internal dead time circuit. If you really want to put a diode don't use the MURA120, 35ns recovery time. Use a small diode as the 1N4148 or a schottky diode
Check also my thread
http://www.diyaudio.com/forums/showthread.php?s=&threadid=116056
probably you can find some useful information about this amp
ciao
-marco
I had the same problem with IRS2092+IRFB4227.
When I was pushing the amp the current limit trips in and mutes the amp for around 0.5s.
Check the voltage on the IRS2092 pin 5 (CSD). If you find it going down to -5V (the VSS rail) when it mutes it means that the current limit trips in.
Current limit thresholds are set trough resitors. Check on the IRS20955 datasheet (there is no information on the IRS2092 datasheet...) how to set these thresholds.
If you have a too inductive path between the low side mosfet source and the COM terminal (pin 10) of the IRS2092 the current limit can trip due to voltage spikes, muting the amp far before the calculated current limit. (I have the same problem on my design).
My amp works fine with 5k6+4k7 for dead time (40nS). If it is not enough increase it to 65ns by putting 8k2+3k3.
Why did you put diodes in parallel with the gate resistors?
By doing this you will change the behaviour of the internal dead time circuit. If you really want to put a diode don't use the MURA120, 35ns recovery time. Use a small diode as the 1N4148 or a schottky diode
Check also my thread
http://www.diyaudio.com/forums/showthread.php?s=&threadid=116056
probably you can find some useful information about this amp
ciao
-marco
IR20955
Hello,
I am using IR20955 as the same schematic as application note iraudamp4. In my output there is a resistor that limits the current and a transformer. I works perfect, but if i use a resistor of 15 ohms or higher. but if I want a lower resistor to supply more current at the output, the driver starts to work and stops without complet all the signal that i send to the input.
Can anybody help me???
Hello,
I am using IR20955 as the same schematic as application note iraudamp4. In my output there is a resistor that limits the current and a transformer. I works perfect, but if i use a resistor of 15 ohms or higher. but if I want a lower resistor to supply more current at the output, the driver starts to work and stops without complet all the signal that i send to the input.
Can anybody help me???
I had a similar problem with starting amplifier. The problem was resistor connecting Vbus+ with bootstrap capacitor.
First I advise You to disable high MOSFET OCP, and increase treshold of low one. As sz_ahong wrote it can be problem with current sense routing, the driver is waiting 500ns and then starts sensing. If inductance of Vs is too big, it can generate spikes triggering overcurrent protection.
Now I'm preparing to build BTL with IRS2092 for 1400W
First I advise You to disable high MOSFET OCP, and increase treshold of low one. As sz_ahong wrote it can be problem with current sense routing, the driver is waiting 500ns and then starts sensing. If inductance of Vs is too big, it can generate spikes triggering overcurrent protection.
Now I'm preparing to build BTL with IRS2092 for 1400W
Hi to all. I had never build amp with IRS2092, I whant now.
Can anyone post schematic with this chip that gona work good with IRFB4227.
I will use volateg from +-50v to +-90V and for now I think I only have to change resistors to vcc and vdd (5.6V drop and 10mA)
Because I never use this chip, can anyone give me 5 minutes and tell me some parts of schematic. How can I set gain, swiching freq (250-350KHz), death time, and overcurent protection..
Can anyone post schematic with this chip that gona work good with IRFB4227.
I will use volateg from +-50v to +-90V and for now I think I only have to change resistors to vcc and vdd (5.6V drop and 10mA)
Because I never use this chip, can anyone give me 5 minutes and tell me some parts of schematic. How can I set gain, swiching freq (250-350KHz), death time, and overcurent protection..
you have good fets, pcb is very important, I would use buffers between IRS and fets.
http://www.inductor.com/irf/iraudamp7s.pdf
page 21, to see what would be good schematic to go by (I would read all of it)
http://www.irf.com/technical-info/appnotes/an-1138.pdf
how to set up everything
http://www.irf.com/technical-info/appnotes/an-1135.pdf
how to make good pcb
http://www.inductor.com/irf/iraudamp7s.pdf
page 21, to see what would be good schematic to go by (I would read all of it)
http://www.irf.com/technical-info/appnotes/an-1138.pdf
how to set up everything
http://www.irf.com/technical-info/appnotes/an-1135.pdf
how to make good pcb
I finsish schematic with lot of help of AN-1138
I attached you schematic. Can you look it and tell me is everuthing ok, with schematic andformulas...
But I stuck with calculation for R2 and R3, also with R4 and R5
On example +-70V @ 4 ohms load
IRFB4227 (Rds 0.024 max.)
AC sine voltage 48V before clip
AC sine current 14A (if speaker imedance fall to 3.5 ohms)
*that means aprox. 7A per voltage rail
-Dead time 45nS
- Rc = 120 ohms (Swich Freq. 300Khz)
- Rin = 47K / 30 = 1.5K (Gain 30x)
- Vaa = Vss = (70 - 5) / 10mA = 6.5K 2W
Now!!!!
- R3 = 10K (1.2 / ((Id x Rds) + 0.6))) = 10k (1.2 / (7A x 0.024) + 0.6))) = 15K
*How can I calculate R2 ???? R2+R3 have to be 10K (AN-1138)
- R5 = 10K ((Itrip x Rds) / 5) = 10K ((7A x 0.024) / 5) = 0.33K = 330ohms
* that means R4 = 9.2 K (this is maybe ok)
I dont know, I did all like in AN-1138
Where is my mestake??
And yes, which PNP NPN pairs can go to buffer?
Thanks
I attached you schematic. Can you look it and tell me is everuthing ok, with schematic andformulas...
But I stuck with calculation for R2 and R3, also with R4 and R5
On example +-70V @ 4 ohms load
IRFB4227 (Rds 0.024 max.)
AC sine voltage 48V before clip
AC sine current 14A (if speaker imedance fall to 3.5 ohms)
*that means aprox. 7A per voltage rail
-Dead time 45nS
- Rc = 120 ohms (Swich Freq. 300Khz)
- Rin = 47K / 30 = 1.5K (Gain 30x)
- Vaa = Vss = (70 - 5) / 10mA = 6.5K 2W
Now!!!!
- R3 = 10K (1.2 / ((Id x Rds) + 0.6))) = 10k (1.2 / (7A x 0.024) + 0.6))) = 15K
*How can I calculate R2 ???? R2+R3 have to be 10K (AN-1138)
- R5 = 10K ((Itrip x Rds) / 5) = 10K ((7A x 0.024) / 5) = 0.33K = 330ohms
* that means R4 = 9.2 K (this is maybe ok)
I dont know, I did all like in AN-1138
Where is my mestake??
And yes, which PNP NPN pairs can go to buffer?
Thanks
Attachments
Do you saw, is everything allright? rest of calculations and formulas?
R4 and R5 calcuation is ok?
I dont undrestand now calcuation for R2 and R3
R4 and R5 calcuation is ok?
I dont undrestand now calcuation for R2 and R3
I made r2 and r3 4k7 and it works fine up to 500watts.
I did the same for the OCSET resistors.
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I find I can drive one pair of 4227's with the 2092 but I need the buffer for two pairs.
I find I can drive one pair of 4227's with the 2092 but I need the buffer for two pairs.
Yes, but I wanna NPN PNP )). Reason is because from Serbia I cant bay from stores in Europe, because Serbia is on black list for all payments and taxes on price of 5eur are 35eur and I dont wanna pay that much for something that I can build with BJT's for 0.1eur and 5 minutes from my house ))
That why I wanna transistor buffer for two pairs..
For one pair of 4227's without buffer: Can it work with 85nS, 300Khz and 10r gate resistor
Thanks
)). Reason is because from Serbia I cant bay from stores in Europe, because Serbia is on black list for all payments and taxes on price of 5eur are 35eur and I dont wanna pay that much for something that I can build with BJT's for 0.1eur and 5 minutes from my house ))That why I wanna transistor buffer for two pairs..
For one pair of 4227's without buffer: Can it work with 85nS, 300Khz and 10r gate resistor
Thanks
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