EveryCircuit - Efficient Amplitude Modulator

hurz

8 years ago

Just use a little chip class D amp as supply for the RF class C amp.

thebugger

8 years ago

Yeah, exactly.

zorgrian

8 years ago

And replace the class C amp with a more efficient class E RF amp?

jason9

8 years ago

@zorgrian, if that was done, then the efficiency would be too high and this would be overpowered! Oh, wait, this isn’t a game. Maybe I’m playing too much Terraria. Anyway, I’m not really sure about this, but looking at a class-C amplifier and looking at a class-E amplifier, I think that the class-E might just be a very highly optimized version of the class-C. What do you think?

jason9

8 years ago

Here’s a version with a class-E instead of a class-C: http://everycircuit.com/circuit/5992413159227392

zorgrian

8 years ago

Yes.. But no! Class E is when the MOSFET is hard driven off and on. Like this the FET does not operate in the liner zone. This results in a huge improvement ineffectiveness efficiency etc. Also, MOSFETs driven like this are easy to achieve using a digital source. MOSFETs dont suffer from thermal runaway!

zorgrian

8 years ago

@jadon9, your modded version is full class E driven by the bugger's audio contraption. Therefore, this is thee most efficient design!

zorgrian

8 years ago

Sorry about wrong spelling of your user name @Jason9

zorgrian

8 years ago

However, having looked at the bugger's audio contraption, i feel compelled to say that it is not necessary nor wise to clock the digital audio amplifier with the same frequency up at 1Mhz. Its far more realistic that such an amplifier would use a much lower frequency.

jason9

8 years ago

You mean the class-D? I’ve heard of class-Ds going well above 1MHz before. I might just have terrible sources or am remembering wrong, but I could have sworn that 1MHz was definitely not the upper limit on class-D frequency. If you mean the class-E, then how are you going to make it output radio frequencies when the inout is well below the radio frequencies without some kind of most likely highly inefficient and distorting frequency multiplier?

thebugger

8 years ago

There are some class D amps working up to 50MHz if I remember correctly - specifically the Tripath's class T amplifier. Anyway the class D part needs some modification with the output filter if you want it to work with a class E amp. Class E amps are best driven with a class F drivers.

zorgrian

8 years ago

Yes, its all possible, but not desirable to have the class D amp clocked at the same frequency as the TX. You risk product mixing, phase problems etc. Better to clock the class D amp at a lower frequency like 50 -100 kHz or so......

jason9

8 years ago

How does a class-T amplifier work? (Not to be confused with a model-T car)

thebugger

8 years ago

I think it works with a self sustained oscillation and advanced feedback systems. It must've not had a lot success on the market, cuz as far as I know, there aren't any class T amps on the market now.

jason9

8 years ago

Ok.

hurz

8 years ago

Wow, our market insider buggzy

zorgrian

8 years ago

Please can he give tips to us on the latest world development. What does he make of non comrade Vladimir Putin (self elect) and his probable connection with the Cambridge Facebook spin job? Who is really pulling the strings? Maybe we need to regulate their power supplies???

thebugger

8 years ago

Can you like not comment shit or something? Totally irrelevant comments :)

zorgrian

8 years ago

So sorry to offend your worshipful eminence; knower of all lessons, VHF is FM, Thy fame and acknowledged superiority within the particular sphere of absolutely everything, oh bugger, is untarnished!

toysinthehood

8 years ago

Dude every time I search something your name pops up. Can you work on a couple circuits with me? Mostly tube, but maybe some effects as well?

thebugger

8 years ago

You wanna work with tubes, nice. I have a few tube amp and oscillator circuits designed.