diyAudio

diyAudio (https://www.diyaudio.com/forums/index.php)
-   Analog Line Level (https://www.diyaudio.com/forums/analog-line-level/)
-   -   The Kuartlotron - keantoken's simple error-correction superbuffer (https://www.diyaudio.com/forums/analog-line-level/251413-kuartlotron-keantokens-simple-error-correction-superbuffer.html)

keantoken 3rd September 2015 07:27 PM

Looks good so far even with an IRF510, which makes it far faster. I was using the wrong lytic in my simulation. The 1MHz resonance also seems to be from the SMPS.

Salas 3rd September 2015 08:16 PM

Quote:

Originally Posted by keantoken (https://www.diyaudio.com/forums/analog-line-level/251413-kuartlotron-keantokens-simple-error-correction-superbuffer-post4440136.html#post4440136)
I just threw one together on the breadboard. I just happened to have a single IRF630. Testing with an SMPS at ~75mA I see resonances at 20MHz (seems to be from the SMPS) and 1MHz.

IRF9630 it could use, not IRF630, thats for the negative polarity. Termination lytic should not be low ESR.

Salas 3rd September 2015 08:25 PM

Quote:

Originally Posted by keantoken (https://www.diyaudio.com/forums/analog-line-level/251413-kuartlotron-keantokens-simple-error-correction-superbuffer-post4440230.html#post4440230)
Looks good so far even with an IRF510, which makes it far faster. I was using the wrong lytic in my simulation. The 1MHz resonance also seems to be from the SMPS.

No problem pretty soon then and its just makeshift. You will test again in your prototype PCB layout. My sim gives 133 deg phase margin at gain=0dB open loop analysis with the original TO-247s and 0.3R ESR 5nH ESL assumed terminal cap parasitics. It never resonated on its dedicated board. Try use no wimpy MOSFET if you will leave it open to user hot-rod. You will sort it out, no worries.

wintermute 6th September 2015 10:47 AM

:cop: Project16's "all in one" posts moved here http://www.diyaudio.com/forums/analo...onception.html

Project16 6th September 2015 11:03 AM

Quote:

Originally Posted by wintermute (https://www.diyaudio.com/forums/analog-line-level/251413-kuartlotron-keantokens-simple-error-correction-superbuffer-post4442686.html#post4442686)
:cop: Project16's "all in one" posts moved here http://www.diyaudio.com/forums/analo...onception.html

Many thank's wintermute! :cheers:

keantoken 10th September 2015 04:46 AM

The IRF510 can handle at least 20W. The main thermal hazard is not FET power, but inadequate sinking, which will be equally destructive for IRF510 and IRF240. Considering this I don't see a point in using TO-247 devices. They are slower and probably not even more stable than the IRF510. With good sinking the IRF510 in this design can handle more than 1A of current.

jean-paul 10th September 2015 05:49 AM

The Lego piece you can use has been tested and proven to work OK.You have permission of the author to use his tested and working design. Why loose time questioning the size of the original parts ? The MOSFETs are not expensive and with TO247 you won't need heatsinks with low current. You could click this Lego piece on your Lego piece and test and measure. Maybe it is because I am a builder and have never simulated anything but things seem to delay without necessity. Sorry but, as said before, IMO focus should be on completing this design to a complete working device that can be used in 99% of cases in everyday life. For this reason I will focus on Project16's design. Good luck with the project, the topology is promising.

Salas 10th September 2015 06:24 PM

Quote:

Originally Posted by keantoken (https://www.diyaudio.com/forums/analog-line-level/251413-kuartlotron-keantokens-simple-error-correction-superbuffer-post4446978.html#post4446978)
The IRF510 can handle at least 20W. The main thermal hazard is not FET power, but inadequate sinking, which will be equally destructive for IRF510 and IRF240. Considering this I don't see a point in using TO-247 devices. They are slower and probably not even more stable than the IRF510. With good sinking the IRF510 in this design can handle more than 1A of current.

As I wrote, the topology lends itself to various devices substitution. If you will decide a fixed constant current then you can pre-package the thermal policy too. If left open to user hot-rod it must be taken into account that the bigger MOSFET has much better RθJC, RθJA, RθCS. Constant current power dissipation is not giving cooling breaks, its not lending itself to the pulsed rating spec of a device. I.e. the power spec gets derated and then again for long life reliability. There is no rule you should leave it open to user hot-rod. You may as well optimize a level. Your choice.

keantoken 10th September 2015 06:34 PM

If there is any significant pulsing in a shunt regulator, then it's already broken. It is straightforward to set operating points according to thermal limits. Am I missing something? A drain resistor should be enough to prevent FET destruction in the prototype.

Salas 10th September 2015 07:15 PM

The SOA curves for power MOSFETS are usually given in pulsed current durations since they are made for switching applications primarily in mind. Thus their constant power abilities should not be based on their 25C case temperature pulsed current spec in the data sheet. That's what I am saying.


All times are GMT. The time now is 11:31 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 17.65%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright ©1999-2020 diyAudio

Wiki