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My thinking was based on considering only that thermal runaway is caused because Vbe is temperature dependent - and the actual temperature / dissipation never entered into the approach.
That will not necessarily stop thermal runaway: it depends on heatsink, supply, voltage, etc.
For runaway to occur, the gain of the loop must be >1: if an initial increase of 1W in dissipation results in a larger than 1W response, there is positive feedback.
1W will increase Tj by Rth, Tj will increase Ic by tempco/Re, and Pd will increase by Vs x Ic.
That is the somewhat simplified outline.
Being too near the limit is not recommended, as small perturbations will lead to huge delta T°'s
Thank you for this advices.
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TRINITY Electronic Design GmbH
I read follow: 288 output power devices in parallel mode/each channel - selected by hand.
Are there a schematic therefore?
Pics are to find under post #18 about
http://www.diyaudio.com/forums/plan...la-information-about-efficiency-wanted-2.html
The amp about
http://www.diyaudio.com/forums/soli...ke-pure-classa-se-despite-low-idle-power.html
uses also a lot of power devices in parallel mode.
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Mr. Andrea Ciuffoli is the designer both of single ended power follower (one stage unity gain amplifier) - go to
http://www.audiodesignguide.com/my/Follower_99c.gif
https://www.diyaudio.com/community/threads/power-follower-99-sound-impressions.8552/
and variants with Sziklai darlington resp. resistor instead CCS
https://www.diyaudio.com/community/threads/pavel-macuras-mosfet-power-follower.45460/
https://www.diyaudio.com/community/threads/sewa-seven-watt-amplifier.66822/#post753744 (post #1)
so as two true complementary power follower variants - go to
http://www.audiodesignguide.com/my/Cool_Follower1.GIF
http://www.audiodesignguide.com/my/Hot_Follower2.GIF
I have found Andrea Ciuffoli's schematics here:
http://www.audiodesignguide.com/my/index.html
other Push-Pull versions with only NPN BjT resp. N-CH MOSFET are only possible with driver transformer like to find under
https://www.diyaudio.com/community/threads/zero-feedback-impedance-amplifiers.42259/
and in a circlotron topology, whose feature is two necessary power supplies and two transformer windings for one power follower stage - but this eliminates the need for driver- and output transformers in the signal path.
for this reason I am most interested in this topology as a power follower.
Are there a circlotron power follower as diy project - i. e. one-stage unity gain circlotron (both class-A and class AB) ?
Thank you for an advice.
This threads don't provide the wanted information.
https://www.diyaudio.com/community/...ar-transistor-circlotrons.175466/#post2337331
https://www.diyaudio.com/community/threads/i-call-it-infinitron.270239/
https://www.diyaudio.com/community/...ind-of-andrea-ciuffolis-cool-follower.385491/
http://www.audiodesignguide.com/my/Follower_99c.gif
https://www.diyaudio.com/community/threads/power-follower-99-sound-impressions.8552/
and variants with Sziklai darlington resp. resistor instead CCS
https://www.diyaudio.com/community/threads/pavel-macuras-mosfet-power-follower.45460/
https://www.diyaudio.com/community/threads/sewa-seven-watt-amplifier.66822/#post753744 (post #1)
so as two true complementary power follower variants - go to
http://www.audiodesignguide.com/my/Cool_Follower1.GIF
http://www.audiodesignguide.com/my/Hot_Follower2.GIF
I have found Andrea Ciuffoli's schematics here:
http://www.audiodesignguide.com/my/index.html
other Push-Pull versions with only NPN BjT resp. N-CH MOSFET are only possible with driver transformer like to find under
https://www.diyaudio.com/community/threads/zero-feedback-impedance-amplifiers.42259/
and in a circlotron topology, whose feature is two necessary power supplies and two transformer windings for one power follower stage - but this eliminates the need for driver- and output transformers in the signal path.
for this reason I am most interested in this topology as a power follower.
Are there a circlotron power follower as diy project - i. e. one-stage unity gain circlotron (both class-A and class AB) ?
Thank you for an advice.
This threads don't provide the wanted information.
https://www.diyaudio.com/community/...ar-transistor-circlotrons.175466/#post2337331
https://www.diyaudio.com/community/threads/i-call-it-infinitron.270239/
https://www.diyaudio.com/community/...ind-of-andrea-ciuffolis-cool-follower.385491/