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Tekko 10th November 2007 09:28 AM

fullbridge carrier class d ideas
This is an idea that i dreamt up last night.

Im positive that itll work what do you think ?

How good are ceramic disc capacitors as output filter ?

Workhorse 10th November 2007 11:41 AM

Where is the feedback network, or you are going for an open loop design......

Tekko 10th November 2007 12:16 PM

Since fullbridge class d is suitable for open loop, ill leave feedback out for now.

Eva 10th November 2007 12:56 PM

There is nothing wrong with feedback, your problem seems to be that you are unable to get a decent power stage working... And a full bridge with a fragile IC such as HIP4080 doesn't make things easier.

You also seem to lack important tools such as a decent workbench to work comfortably and a current limited symmetrical power supply (may be DIY) to avoid frying things on small mistakes.

Tekko 10th November 2007 02:32 PM

Maybe im just too lazy to build dedicated supplies.

This is meant to be a subamp so it doesent have to be perfect.

Tekko 10th November 2007 06:53 PM

This will go into etching tomorrow:

I have chosen a switching freq of approx 200KHz and estimated possible power output to 250W from a 33V supply. The 7815 can handle 35V so i cannot run very much power due to that.

What do you think would be good values for the deadtime resistors, 10k ?

fernando_g 19th November 2007 07:09 PM


Originally posted by Eva
And a full bridge with a fragile IC such as HIP4080 doesn't make things easier.

This is weird... I had also considerd the HIP4080 for a project that never left the planning stage.

I've had some reliability issues with other devices from Intersil, formerly known as Harris.
But what has been your experience with the HIP4080? I had thought this device was OK. I may be completely wrong, though.

Tekko 19th November 2007 07:23 PM

This board never made it to the assembly and soldering department.

Two caramps caught my interest, both uses HIP4080AIP, one is running atm.


fernando_g 19th November 2007 07:28 PM

Re: fullbridge carrier class d ideas

Originally posted by Tekko
This is an idea that i dreamt up last night.

To generate your VDD voltage, which is VCC/2, I would use a TLE2426 precision ground reference from TI.

Also tho generate the traingle wave, select an opamp with symmetrical output swings on the comparator output. And at 200 Khz, you may also be hitting the slew rate limits of the TL082.
Otherwise, the trainglewave may be nonlinear. And remember, nonlinearity means distortion.

m-tech 20th November 2007 10:15 AM

2 Attachment(s)
It's much better to use LF353 instead of TL082. Changing the op-amps in triangle wave generator will change operating frequency and triangle wave amplitude ( try to simulate first ).

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