Hello
I have 2ch class D DIY apm. Iraudamp7 conception. The first is fine, the second has a problem. The sound is good but 0,8 - 1V DC at the output (not signal). The DC voltage increases with the load and the external DC protection switches off. I replaced the transistors, but that didn't help. May be IRS2092 defective? What else can I check?
Thank you for any help.
I have 2ch class D DIY apm. Iraudamp7 conception. The first is fine, the second has a problem. The sound is good but 0,8 - 1V DC at the output (not signal). The DC voltage increases with the load and the external DC protection switches off. I replaced the transistors, but that didn't help. May be IRS2092 defective? What else can I check?
Thank you for any help.
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Check the PWM is providing equal cycles.
If the oscillator is not a true triangle, an offset will apear on the output for obvious reasons.
If the oscillator is not a true triangle, an offset will apear on the output for obvious reasons.
Since the DC changes with loading, it must be related to error control/feedback (DC loop gain). Unlikely, but also check the bootstrap power supply VBS(15-13) and dead-time settings.
Is this lately, or has it been like this since the PCB was assembled?
Is this lately, or has it been like this since the PCB was assembled?
Hi stepper
I recently had similar problems. When turning on the amp it was fine, after some minutes, it started drifting quite some.
But I was lucky using a dual output SMPS which just shifted the ratio between + and - so the output of the amp was still around 0 😉 ....
I newer found the real issue, but ended up desperately changing all the caps in the input half.
Maybe it was a bad soldering .... maybe the use of X5R caps in the oscillator instead of N0P (though I can´t really see why .... though it was only for test purpose anyway) ...
First step is as newvirus2008 says check pre-filter waveform.
If implemented correctly, I have found that the IRS2092 circuit is really well at keeping a good low DC
Do you have a schematics you could share?
Share good pictures the PCB also, for visual inspection and help
Kind regards Baldin
I recently had similar problems. When turning on the amp it was fine, after some minutes, it started drifting quite some.
But I was lucky using a dual output SMPS which just shifted the ratio between + and - so the output of the amp was still around 0 😉 ....
I newer found the real issue, but ended up desperately changing all the caps in the input half.
Maybe it was a bad soldering .... maybe the use of X5R caps in the oscillator instead of N0P (though I can´t really see why .... though it was only for test purpose anyway) ...
First step is as newvirus2008 says check pre-filter waveform.
If implemented correctly, I have found that the IRS2092 circuit is really well at keeping a good low DC
Do you have a schematics you could share?
Share good pictures the PCB also, for visual inspection and help
Kind regards Baldin
Baldin said:
Sensible advice, but the OP please note that that wasn't me, but JonSnell Electronic. Thanks.
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