output stage of tda2030a

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hentai

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Hello, i wonder if anyone has an idea or mb a schematic of whats under the hood of a tda2030a...
I'm thinking can these chips (and others) be biased into class a by adding a current load between output and one of the supply rails like with opamps.
Any input is appreciated! Thank you.
 

I think you might be correct. They certainly run as class AB I believe under normal operation. I think their outputs are just a complimentary pair of power transistors. Did you see the datasheet? It may not show that much detail so really nobody can know for sure.
 
I would have thought not?, there's a specific reason that method works on one particular type of opamp - it's not going to work on a power amplifier, or indeed other opamps.

In any case, the 2030 is already a fairly decent performer, why do you want to alter it?.
 
well there was a sell out thing at one of my local stores and they sold tda2030a with about 0.3$ so i bought a bag full of them . I was just curious if it can be done... thinking mb i could use it as a class a headphone amp or in tri-amping for those high freq.
Nigel i find it curious why u say that the method only works on one type of opamp... do u mean the lm324?
i found the internal schematic of the tda2040... could it be somehow similar?
in this case couldnt the output stage be forced to work single ended?
 

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You need to consider what the external resistor does on an LM324 - essentially it's a pullup resistor, so that provides the current rather than the other transistor. This is only possible because of the low output current it provides - for a power amp, assuming it could be done?, it would require a VERY low value resistor, which would destroy the bottom transistor.

But I'll say again, why not just use them 'as is' they are pretty respectable devices, 0.1% distortion at 8W into 8 ohms.
 
You are right... but i can afford experimenting
and i think resistors can be replaced with an active load? i remember i've seen it done on opamps with some cascode with fets... if u keep the bias curent at bay could it still be dangerous for the device?
Thx for ur help!
 

The mod for the LM324 is to remove the excessive cross-over distortion in the chip, the problem doesn't apply to the TDA2030. I don't see how an active load would help?, it would only be worse than a resistor.
 
hmm i got'em from a store... dont know if they will ship but i live in Romania so shiping to US will probably cost more than the ics...
Cheers!
 
The fanatics at the headphones amplifier forum added a class-A load to the OPA2134 opamps they use, to reduce the 0.00008% distortion!!!
 

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