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Old 5th March 2012, 11:24 AM   #11
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Quote:
Originally Posted by emilvv View Post
Hello All,

Please find attached latest schematic.

I need your remarks, corrections, suggestions ... etc. about everything EXCEPT power stage - IR2110+IRFP4227 - it is not ready and will be improved!

Please correct schematics, C and R values .... ...etc ...

Remember that this is only SUB amp - up to 200-300 Hz !!!!

Can you help men with correct values for : D5, D6, R7, R8, C6 and C7 ??

Regards,

Emil
The questioned values are usually determined by experimentation or simulation. But here is a quess calculation:
Charge time constant of capacitor tau_charge=(R7+Rout)*C6
Discrage time constant of capacitor tau_discharge=(Rout)*C6
where Rout is the output impedance of the comparator.
The approximate dead time is the difference between this two time constant: delta-tau=R6*C6
This is an approximate only, the dead-time valuse should be experimented. Increasing dead-time decreases the idele current (due to cross-conduction), but also increases THD. There is usually an optimum dead-time value, where THD is small, and losses also small, because the antiparralel diode loss minimalization.

Keep in mind that IR2110 has a serious issue when driving with short pulses. Since you are using a fast comparator (this is good of course, but), you may encounter problems. Th RCD network may help you with this, not only with dead-time.
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Old 5th March 2012, 11:36 AM   #12
norazmi is offline norazmi  Malaysia
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emilvv, what is your targeting power (rms)? load(4-2-1 ohm)? And lorylaci already stated about deadtime, of course you need to experimented for the optimum value, state ur target here, seems ur preparing for high power and maybe 1 ohm load?
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Old 5th March 2012, 11:43 AM   #13
emilvv is offline emilvv  Bulgaria
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Default Hello,

Hi,

My load is 8 ohm ... But you may post your answer for 4 and 2 ohm - if someone want's to use this values ...and test the project ....

Please correct everything except power stage .... I have to add current limiting .... protection .... so schematic is not complete in this part ..

Regards,

Emil
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Old 5th March 2012, 01:16 PM   #14
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Quote:
Originally Posted by emilvv View Post
Hi,

My load is 8 ohm ... But you may post your answer for 4 and 2 ohm - if someone want's to use this values ...and test the project ....

Please correct everything except power stage .... I have to add current limiting .... protection .... so schematic is not complete in this part ..

Regards,

Emil
If you are a beginner, first design only the amp, without everything else. You will be happy if only the amp works. The schemtic is the easier part, the layout is much harder way to go.

So 8 ohm, 50V full bridge, I still reccomend TAS5630. Or for bigger supply voltages here is an idea you can start on:
Click the image to open in full size.
Click the image to open in full size.
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Old 5th March 2012, 01:26 PM   #15
emilvv is offline emilvv  Bulgaria
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Default Hi

I don't want to build TAS5630 amp ... THD+H = 10 % - I am beginner in class d, but not deaf !!

I want go as I requested .... not with HIP4080 ... or similar ways ...

Can you help with suggestions for LM361 --> 2 x IR2110 --> MOS --> T200-2 .... ??

That is what I need help.....

Regards,

Emil
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Old 5th March 2012, 01:37 PM   #16
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Quote:
Originally Posted by emilvv View Post
I don't want to build TAS5630 amp ... THD+H = 10 % - I am beginner in class d, but not deaf !!

I want go as I requested .... not with HIP4080 ... or similar ways ...

Can you help with suggestions for LM361 --> 2 x IR2110 --> MOS --> T200-2 .... ??

That is what I need help.....

Regards,

Emil
TAS5630 has a THD of 0,03% at medium power (1-50W). 10% is for 150W at 8 Ohm from 50V supply. At 120W it is 1%, and at 100W it is 0,1%.

First of all you must decide what you want!
You said 8 ohm and 50V single supply. But what THD levels and complexity you choose? What is your planned switching frequeny? Do you want fixed frequency PWM, hystereis or UcD self-oscillation. Since in the topic you said UcD, but your latest schematic is a hysteresis oscillation amp.

From 50V supply you cannot get really more than 100W at 0,1% THD, because of the modulation limit. Because IR2110 has limited pulse width, it really limits modulation. For 50V, you also should not use a 600V driver.
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Old 5th March 2012, 01:49 PM   #17
emilvv is offline emilvv  Bulgaria
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Default Hi

Thank you !

That is answer that I am waiting for .. !

The power that I have is 50-56 V - single supply .... I don't want to change it .. so let me to use it ....

Second I have 8 Ohm load ... BUT it can be 4 Ohm .... Is it better for schematics .... ???

Please forget about TAS5630 for now .... please .....

"From 50V supply you cannot get really more than 100W at 0,1% THD"
- if we speak only about SUB amp - 0-300 Hz - how much is the possible MIN THD ??

"Do you want fixed frequency PWM, hystereis or UcD self-oscillation" - which kind ( topology ) of this amps can do less THD with 50V + 4/8 Ohm load ??

"For 50V, you also should not use a 600V driver" - please suggest me driver ...

Regards,

Emil
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Old 5th March 2012, 02:09 PM   #18
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Quote:
Originally Posted by emilvv View Post
Thank you !

That is answer that I am waiting for .. !

The power that I have is 50-56 V - single supply .... I don't want to change it .. so let me to use it ....

Second I have 8 Ohm load ... BUT it can be 4 Ohm .... Is it better for schematics .... ???

Please forget about TAS5630 for now .... please .....

"From 50V supply you cannot get really more than 100W at 0,1% THD"
- if we speak only about SUB amp - 0-300 Hz - how much is the possible MIN THD ??

"Do you want fixed frequency PWM, hystereis or UcD self-oscillation" - which kind ( topology ) of this amps can do less THD with 50V + 4/8 Ohm load ??

"For 50V, you also should not use a 600V driver" - please suggest me driver ...

Regards,

Emil
THD levels below 0,1% is pretty hard with Class-D, need a lot of optimalization. It is not really frequency dependent! It is mainly limited by the supply and the modulation. What don't you understand in it?

Which topology will have less THD? I cannot tell, because it depends heavily on lot of other factors. (supply voltage, load, dead-time setting, feedback, driving network) UcD is usually the simplest, and gives low THD levels, but as I said THD can be high with unproper dead-time selection and others. Ucd has a con: limited loop gain.
Fixed freq PWM has a great pro with fixed freq, which you can syncrhonize to other channels and/or to power supply (reduced interferrence). Also gain can be easily changed. Hysteresis oscillation has less frequency change, but it is pre LC feedback, so its cons comes from it.

TI has a lot of 120V drivers UCC27xx series. Intersil has HIP4081 (which is a full-bridge driver only, no comparator). But using HIP4080 with integarated high-speed comparator can raise your modulation limit. HIP2100 is half-bridge driver of Intersil. IRF has IR2010 which much faster than IR2110 (don't know if has the same minimal pulse width error as IR2110).

You can also use a discrete gate drive.
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Old 5th March 2012, 06:48 PM   #19
savu is offline savu  Romania
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Default Try Something like this

You could try something like this:
Attached Images
File Type: jpg singlesupply.jpg (138.1 KB, 630 views)
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Old 6th March 2012, 12:30 AM   #20
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Default Try Something like this

Hi Savu
hello just some tips i need to know before i start this project
1 will single PCB be good enough for this amp as i have little experience in designing ds pcb
2 can IRFP 250 N be used for experimental purpose once amp working irfb4227 will
be used
3 ultra fast ic LT1711 ANY substitutes this ic hard to get in my city
savu with little help from you i think i can suceed in my project
thanking you
sameer x1
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