cheap usb oscilloscope for measuring amplifiers

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For the MosFet selection you must know your desired power. This will lead to a certain requirement for voltage , current ratings and Rdson of the MosFet.
You should not use MosFets which are much to strong, because they are more difficult to drive. Also above 100V it is difficult to find types with low Qrr of the body diodes.

1. Define the proper MosFet rating.
2. Search for a MosFet with the best trade off from Qrr (most critical), Qdg (second critical) and Qgs (third).
3. Design proper low side and high side driver + level shifter, or decide to use a halfbridge driver IC.
4. Have a look to the switching behavior of the power stage before you build the entire amp. Layout is one of the keys for good results.
5. Complete the amp by your favourite modulation principle and of course also output filter.

Point 4 might influence your consumption of acetylsalicylic acid products.
;)
 
choco

ok..i decided to make a sub amplifier..i did a 20hz-20khz in the past..but didnt work well..now i have tl072 ne5532 and lm4562..i will use one of them.2 ir2110..i decided to make full bridge sub amplifier..i want to have good bass and low thd..i have 16amperes 33,6volts toroidal transformer.and i want 200watts rms .what do you prefer?are st stripfets good choice?
cherry is a naturel aspirin..do not use much asetilsalisilik asit (in my language)..harmful for stomach and intestines ;)
 
So you are going for a single supply around 50V unloaded, correct? With a full bridge this could work to get something around 200Wrms into 4 Ohms...
For the MosFets you should search multiple brands and compare their types around 80V (at least 60V) / 15A.

Post a comparison list with brand&type, voltage rating, current rating, Rdson, Qrr, Qdg & Qgs. Then we can see...

If you really only want it for a sub, then there is not need at all for switching frquencies above 100kHz.
I think your OP amps are OK for an error correction gain stage, but they will not satisfy you in comparator operation.
 
choco

as comparator i have lm360 and lt1016..i made a triangle wave generator with cd4069 gates as intersil hip4081 evo board..
yes 33,6*1,41 it will be 47volts...mosfets have 60volts vdss

there are some choices about mosfets

STF40NF06
STP60NF06L
STD20NF06LT4 it is d pack:)
and also irf540 st
what do you think?is input capacitance not important?
what can i do ?may i use feedback or not?it will be a full bridge?does it really need feedback;)
 
Re: choco

umut1001 said:

what do you think?is input capacitance not important?
what can i do ?may i use feedback or not?it will be a full bridge?does it really need feedback;)


Input capacitance is corresponding to Qgs. It is important.
Reverse transfer capacitance is corresponding to Qgd. It is very important.
I prefer to look at the charges instead of the capacitances, because the capacitances are nonlinear capacitances. Furtheron you have to take ino account that Crss has to be charged to much higher voltages than Ciss, means even a small looking Crss might need more charge than the bigger Ciss.....

It does not really NEED feedback, but in most class D designs it is quite fortunate.

Full bridge vs halfbridge:
The full bridge has the disadvantage of double component count.. Also you have two times the dead time related distorsions.
But the advantage is that you have less issues with the poor freewheeling diodes of high voltage MosFets, because you do not need high voltage types.
Another advantage is that a full bridge does not cause so much supply voltage pumping.
 
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