Another amp with IRS2092

[luka]

Hi

Having a 250W amp driving a small 16cm speaker will for sure blow it up shortly

I didn't say you *have to* drive them with that, you have gain, turn it down, you can use only 50w if you would like to, but what I am saying amp will have better working condisions if you won't push it to its limit.

I have installed the two amps in my car and, believe me, still 120+120W + 900W on the sub is loud as hell. I don't think I need more power....

Nah that is just right for short say 10-15min car trips to local shops , I have well you can see what I have...it is just right, but note that I am young not old, no offence of course

I don't think I will be building this amp anytime soon, coz I would have to order IRS and I have to many amps already . But if time comes...

[mag]

Hi all,
yesterday I blew up one mosfet of the SMPS (and the related gate driver too...).

The amp was installed in the car for about two weeks without showing any problem.

Yesteray when I switched on my radio I heard a click noise from the amp and then it was dead. The two parallel 20A fuses were exploded.

I noticed that only one side of the push-pull was blown and after having replaced the mosfet, the gate driver and the fuses the amplifer was back alive as before.

I suspect there is a problem with the PSU soft start that creates high inrush current at power up. Is it possible?

I control the SMPS IC trough a timer linked to the remote conection. After 2 seconds that remote is high the Shutdown pin of the SG3526 is released and the SPMS starts.

My suspect is that the shutdown pin does not control the soft start and so the SMPS starts at full duty cycle as soon as the shutdown is released.

Now I have connected the shutdown signal to the reset pin of the SG3526 and it seems to work well.

Can it be the source of the problem? Running an SMPS without soft start can destroy a 180A mosfet? This sounds strange to me.

Thank you

ciao

[savu]

Originally Posted by mag

Hi all,
yesterday I blew up one mosfet of the SMPS (and the related gate driver too...).

The amp was installed in the car for about two weeks without showing any problem.

Yesteray when I switched on my radio I heard a click noise from the amp and then it was dead. The two parallel 20A fuses were exploded.

I noticed that only one side of the push-pull was blown and after having replaced the mosfet, the gate driver and the fuses the amplifer was back alive as before.

I suspect there is a problem with the PSU soft start that creates high inrush current at power up. Is it possible?

I control the SMPS IC trough a timer linked to the remote conection. After 2 seconds that remote is high the Shutdown pin of the SG3526 is released and the SPMS starts.

My suspect is that the shutdown pin does not control the soft start and so the SMPS starts at full duty cycle as soon as the shutdown is released.

Now I have connected the shutdown signal to the reset pin of the SG3526 and it seems to work well.

Can it be the source of the problem? Running an SMPS without soft start can destroy a 180A mosfet? This sounds strange to me.

Thank you

ciao

Hi Mag,

By using Soft Start pin with the protection circuitry you can do wonders on SG chips.

Just short the SS capacitor with a transistor whenever the protection trips.
The SMPS will stop, then it will restart fron 0 to 50% duty cicle because the soft start capacitor will recharge. during this everithing will start gradualy. If the protection will trip again because let's say you have a short or something, the smps will restart from 0 to 50% duty again. your smps will be protectet and it will allways start from 0 to 50% duty no matter what.
from what i know Shotdown pin doesn't do soft start. so after an unwanted thing that trips the prot it will just start 100% power and the inrush courent will blow fets if they are not big enough to survive.

Best regards,

Savu

[ultra]

Originally Posted by mag

motherboard close up

Mag,
this is AMAZING work....Excellent ! your pcb is professional-state of the art
Bravo!