Discrete Class-D anno 1986

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Baldin

Baldin

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Joined 2005
sensibleaudio.dk/
Just thought I would share my first encounter with class-d amplification.

This artichle is from 1986, from the now closed Danish magazin "Ny Elektronik" ...... so I've had it in my drawer for 20 years :spin:

It's unfortunatly in danish, but the diagram and component list is universal :)

We're talking about a total construction with only 5 transistors .... :cool:

5W from a single 12 VDC ... distortion .... not known .... switch freq 100 kHz

Maybe it could be adopted to some more power and split supply.

I know it isn't high end, but I think it's quite intriguing anyway ;)

UcD = 14 transistors ....... this one 5! :D
http://home20.inet.tele.dk/audio/Class_D_Ny_Elektronik_1986.PDF
 
BWRX

BWRX

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Joined 2005
A single 12V rail with a half bridge output stage will only give you 4.5W peak (2.25Wrms max) into 8ohms and 9W peak (4.5Wrms max) into 4ohms. And that's assuming a full output voltage swing and the output stage can provide enough current into those impedances.
 
RX5

RX5

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Joined 2004
beamx5.solarbotics.net/index.htm
BWRX said:
A single 12V rail with a half bridge output stage will only give you 4.5W peak (2.25Wrms max) into 8ohms and 9W peak (4.5Wrms max) into 4ohms. And that's assuming a full output voltage swing and the output stage can provide enough current into those impedances.
Click to expand...


Brian,

could you give me the maths here... I cant seem to remember WHERE I saved those equations.. also, how do you calculate power output with dual polarity supply (+/-)...

:D
 
Baldin

Baldin

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Joined 2005
sensibleaudio.dk/
RX5
There is not that muct to read about the workings in the article.
I think you would need to simulate to get a better understanding and to find ways to improve. .... could be quite usefull to have a very simple desig for, say 20W .... would be enough to drive a small active speaker for the PC or something.

Then we'll of course also need a similar simple SMPS :D
 
RX5

RX5

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Joined 2004
beamx5.solarbotics.net/index.htm
Baldin said:
RX5
Thee is not that muct to read about the workings in the article.
I think you would need to simulate to get a better understanding and to find ways to improve. .... could be quite usefull to have a very simple desig for, say 20W .... would be enough to drive a small active speaker for the PC or something.

Then we'll of course also need a similar simple SMPS :D
Click to expand...


hhhmmmmmm WHY didnt I think of it?? hahahaha sure would be nice to simulate and improve... :angel:

in a few days....:smash:
 
BWRX

BWRX

Ex-Moderator
Joined 2005
To calculate peak theoretical power output you just need to know the maximum output voltage across the load and the load impedance.
Peak power = (V^2)/R
RMS power = ((V/sqrt(2))^2)/R = (V^2)/(2*R)

For a single ended output the maximum theoretical output voltage is half of the total rail voltage. For a bridged output the maximum theoretical output voltage is the rail voltage.

Edit: Baldin beat me to it :)
 
RX5

RX5

Member
Joined 2004
beamx5.solarbotics.net/index.htm
BWRX said:
To calculate peak theoretical power output you just need to know the maximum output voltage across the load and the load impedance.
Peak power = (V^2)/R
RMS power = ((V/sqrt(2))^2)/R = (V^2)/(2*R)

For a single ended output the maximum theoretical output voltage is half of the total rail voltage. For a bridged output the maximum theoretical output voltage is the rail voltage.

Edit: Baldin beat me to it :)
Click to expand...


thanks!!!

:smash:

I love furoms..:D knowledge is POWER in RMS :p hehehe


need to sleeeeeeeeeeeeeeeeeeeep.... zzzzzzzzzzzzzzz
 
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