schematic of my future D amp for the pb12

[38628]

the noise figure is 100mv rms, frequency is a mix of the input signal and the 400khz.
Yould you think it is a lot?

 

[classd4sure]

Hmm, it's higher than some and alot lower than others, seems like a very respectable figure. You do just mean the left over ripple from switching right?

That's all ultra sonic anyway so it can't be heard, it just goes towards EMI, a common mode filter can be used on your output to help cancel it out a bit more, if you plan on using long speaker wires.

You can probably find alot of areas to impove things if you keep looking.

 

[38628]

i mean the residual noise on the 12v vcc for the ir2011.

the output just get a 200mv rms @400khz...not audible at all.

 

[classd4sure]

Doesn't seem like alot to me, less than 1%?

 

[Pierre]

Following with the bootstrap capacitor discussion, I use a 10uF tantalum SMD.
My driver's supply is a 12V regulator with 100uF || 100nf bypassing.
It works fine for me and clips well.

Best regards

 

[38628]

Hi Pierre, do you have any series resistors?
I wil try today a simple 7812 regulator and some bypassing caps.

I also found out that the ripple i got is also common to the -v rails of my power supply, so as long as it will be there, it will be all over the place.

see older post with the original schematic.

thanks.

 

[Pierre]

No, I don't have series resistors.
I get the 12V from a 7812 as well, and it is well bypassed both at the input and at the output.

Best regards,
Pierre

 

[classd4sure]

Hi guys,

That's the same regulator IC I'm using to power the drivers with, handles 1 amp peak I believe? It works with 100uF anyway.

Also using another 100uF to bypass the IC with.

I notice they have a 470uF bypass cap on the lower rail, but not on the upper rail. Maybe you could try adding one there as well, right before the upper mosfet, it will help contain switching transients. Those should both be as close as possible to the mosfets.

Regards

 

[38628]

There is 2x470uf on my design, very very close to both mosfets, as well as 0,1uf on both top and bottom ground plane, directly at the mosfets. The residual noise on the vcc lines is still very low at ±100mv rms.

I have one of my friend who have listened to this amp, he want me to build asap a 5ch amp version of this amp for his 5.1 kit.

He his also very impressed by the sound quality and the punch it have.

 

[38628]

Hi, a litle update on this project. I have changed my regulator with a lm7812. No major improvement, just less components on the board.
I have done another cad wich includes some of the protections (turn on relay and dc protection)
The board is still very small, and now includes everything for a safe stand alone operation.
Simply add a good power supply from 25 to 60 volts and your gone !!


cheers group.

 

[Kenshin]

One old Motorola Appnotes on motor driver applications even suggest adding some shoot-through to reduce the high di/dt of body diode reverse-recovery.

anyway,resistors || diodes is good enough to prevent shoot-through.

Well, IRF has very good THD and noise figures with no dead-time control apart from the resistors || diodes in the gates.

Do you think that mosfets can be killed by allowing some shoot-though if it lasts in the order of 100ns? What are other possible causes of instantaneous mosfet failure? (I am not talking about overcurrent/overtemp)

Could you point to the mentioned Bruno's discussion, Charles?

Best regards,
Pierre

 

[prb123]

Any chance of getting a parts list for the schematic you posted?

 

[38628]

sure. but it still under prototyping.

I am implementing active protections on it, controled by a microcontroler (12f675). Yes, i do PIC programming as well.
features: dc protection, over voltage (bus pump) and under voltage, delayed turn on with relay protection output/instant relay turn off when shuted down, wich the IRAUDAMP "as is" cannot do.
Differential input (opa2134)so one could use these boards easely with either balanced lines or to bridge 2 modules together. I am still working quite hard on it. It differs a lot from the original design from IR.
I will post the updated schematic soon, with all the parts and a bom.
You can see the original schematic on IR pages, search IRAUDAMP.
I will post also the gerbers files for both units, the initial one that you see on this thread without protections, and the "full" board, wich is only half inch longer 😀

Since i am into this all day, i may get a quote on a run of PCB from my usual maker if someones interested.
Maybe someone like barebones pcb could be good to ?

 

[rlv]

Hi.

How is your project doing these days?

Have you come to a satisfying result yet or are you still prototyping?

Rasmus

 

[38628]

Hi, i am still working on the PCB whenever i can, to make it smaller, but essentialy, i am playing with the PB12 module.

the ir amp module is still connected as the main amp in my stereo system (mono!) , and it stills plays very well. I am very proud and happy of it.

Maybe, i will call a run of PCB soon. I will let you know then.

 

[rlv]

May I ask how your schematics look like at the moment?

I'm considering doing an IRF clone myself so any ideas are welcome...

Rasmus

 

[38628]

Hi.

Yes i can show you my schematic. It is not realy up to date, but shows whats going in a lot.

I think some components value are not ok too, mostly into the protection parts.

 

[rlv]

Thanks a lot. It looks interesting.

I will probably look a bit to your side when designing my own. Any improvements will be returned 🙂

Rasmus

 

[Bent]

PCB interest

Hi, I for one am very interested.

I have a sag if IRF540's and +/-48v SMPS in my shed waiting for a home, and these are just the answer😀

Please let us know when the CB's are ready, I will likely buy 10-16 for my surround sound project.

Cheers, Graeme

 

[Pierre]

Bent, may I ask you if your +/-48V SMPS is offline or from a 12V DC/DC? Have you built it yourself or is commercial?

Thanks and sorry for the off-topic question.

Pierre