I already checked LM1875, 1876 and 3886 datasheets; with LM1876 and 3886 there is no problem that they have a bit under 100Khz but LM1876 they only say 70Khz power bandwidth..
But at this point i have a transformer calculation problem.
- First, i dont know detailed trafo calculations,
- Second, the trafo has to be 80Khz tuned
- Third, primary coil must have 8 ohm exact inductive load at 80Khz.
- Fourth, this trafo must handle at least 20W power.
And naturally i cannot calculate a working trafo that can realise that needs!
I know that, here is not place for trafo calculations but may anybody calculate that trafo for me?
Thanks a lot.
But at this point i have a transformer calculation problem.
- First, i dont know detailed trafo calculations,
- Second, the trafo has to be 80Khz tuned
- Third, primary coil must have 8 ohm exact inductive load at 80Khz.
- Fourth, this trafo must handle at least 20W power.
And naturally i cannot calculate a working trafo that can realise that needs!
I know that, here is not place for trafo calculations but may anybody calculate that trafo for me?
Thanks a lot.
In the following website, you can see a large amount of the power op amp product and the technical documents about the pzt driver using their products.
http://www.apexmicrotech.com
In my experience, their product works well on the pzt actuators.
http://www.apexmicrotech.com
In my experience, their product works well on the pzt actuators.
No. Its for piezo ceramic motor driver. And i will use a signal generator to change frequency. So the amp must have 70-80Khz bandwidth at least.
My piezo pads have 65pF capacitance. At this frequency (75Khz) it looks like short circuit from the amp output.. Do you think LM3886s can handle this?
So if i use two LM3886 bridge and feed with +/-38v i can have 38x4=152v swing teorically. Is it? But i guess there is another problem that;
My piezo pads have 65pF capacitance. At this frequency (75Khz) it looks like short circuit from the amp output.. Do you think LM3886s can handle this?
I havent made any calculation! Just a friend said that! Sorry.
Hmmm i remember Netron7 said something and i add some otherthings.. Never mind.
Sorry I can't look up everything for this design.
I do not have the time.
Check out Google
http://www.google.co.in/search?hl=en&q=ferrite+core+calculations+for+100khz+operation&meta=
and this
http://www.ee.latrobe.edu.au/~djc/UltraSonics/Ultrasonics.htm
http://www.google.co.in/search?hl=en&q=80khz+piezo+driver+design&btnG=Google+Search&meta=
seems to have lots of links.
I do not have the time.
Check out Google
http://www.google.co.in/search?hl=en&q=ferrite+core+calculations+for+100khz+operation&meta=
and this
http://www.ee.latrobe.edu.au/~djc/UltraSonics/Ultrasonics.htm
http://www.google.co.in/search?hl=en&q=80khz+piezo+driver+design&btnG=Google+Search&meta=
seems to have lots of links.
Here is another one .
http://www.lab-systems.com/products/amplifier/a303.html
Gives you an idea of what they are using in the market !
Looks like you can rig up a simple class B amp with MOSFET's in bridged mode. Should be simple and no need for transformers which can be a big pain in itself.
You want 150V pp. So each bridge should give 75 vpp.
With split supplies you need AT LEAST +/- 45 volts supplies. More to take into account supply drop on load and transistor losses.
Looks like 0.5 % distortion is OK. So a class B or 'almost on' biased transistors might be OK . I think !
Comments anyone ?
http://www.lab-systems.com/products/amplifier/a303.html
Gives you an idea of what they are using in the market !
Looks like you can rig up a simple class B amp with MOSFET's in bridged mode. Should be simple and no need for transformers which can be a big pain in itself.
You want 150V pp. So each bridge should give 75 vpp.
With split supplies you need AT LEAST +/- 45 volts supplies. More to take into account supply drop on load and transistor losses.
Looks like 0.5 % distortion is OK. So a class B or 'almost on' biased transistors might be OK . I think !
Comments anyone ?
1.) Do you need to be able to vary the output voltage ?
2.) Do you want a bandwidth form 70 kHz to 80 kHz or do you need from DC up to this frequency range?
If the voltage can be fixed AND the output signal is narrow-band (i.e. 70 to 80 kHz) then you could as well use a class-C output stage and the voltage-transformation can be done purely by the use of caps and inductors.
Regards
Charles
2.) Do you want a bandwidth form 70 kHz to 80 kHz or do you need from DC up to this frequency range?
If the voltage can be fixed AND the output signal is narrow-band (i.e. 70 to 80 kHz) then you could as well use a class-C output stage and the voltage-transformation can be done purely by the use of caps and inductors.
Regards
Charles
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