How Class D Amplifiers Work part 1 with EPC GaN FETs

This video is about How Class D Amplifiers Work part 1. This Class D amplifier uses GaN FETs from EPC. In this video I explain how the output stage works in a Class D and show how the square wave can reproduce a sign wave.

Class D Amplifiers are very efficient and can be made much smaller than a Class A/B amplifier of the same power. Also, this board that I am using is an eval card that was loaned to me by EPC to do these videos. #howclassDworks #howclassdamplifierswork #EPC #GaN #GaNFET

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[jackstanek]

Great video! Very informative, thumbs up!

[thatradkid]

7:29 based on that tip alone i subbed. you're talking real lab talk and i like it.

[makarov]

I've recently purchased a Fosi Audio DAC class D audio amplifier that is about the size of a box of kitchen matches. It produces about the same audio power that my old Pioneer 100W per channel amp does. And it sounds wonderful! Those really low bass notes come rolling through unimpeded. This thing is really efficient. Ahead of it is a tube preamp with tone controls to set the highs and lows. When I'm really cranking this thing all over the house; she barely gets warm! Phenomenal!

[paulhackney]

Holy CRAP! I've never seen so many DMM's in one place before, haha!
The way you describe this reminds me of how AM and FM works. - Pauly

[thatradkid]

this video is getting better with every second!! i really like this . its like i'm sitting with you on the bench. you're doing a really good job at explaining things! this is so helpful

[ronkessler]

Great Job! YES I would love to see your scope images and more details about how the Comparator signals look and a closer look at the currents in the MOSFETS

[gregkirby]

Thank you for the profanity free education. It is very appreciated! God bless you sir

[deankay]

As a dealer tech, I know GM dealer parts. Wiring my son’s early 80’s car into the 21st century is my job. This led me to Mini ANL fuse distribution blocks for 3-4 circuits. After finding audiophiles discussing class-D amp and fuse sizing led me to you. Boy, that was long! They are actually taking output in watts, de-rating by 20%, dividing by system voltage at 13.8 volts and screw it up worse. We know P-I-E is the formula but a 1, 400 watt amp divided by 0.8= 1, 750 watts? What? Then divide system voltage 13.8Vdc, =128 amp fuse to protect the circuit. I have amp clamps, DMM and a lab scope but what am I missing?
I truly think their abacus is a few beads shy of full.
I have been an ASE Master Tech since 1978. I taught 6 electrical classes (Of 30) for ACDelco in 13 Midwest tech schools much less hold tech seminars for over 100 techs, owners and colleges instructors that were 4hrs long. Am I missing something here? Why use rated output of a “Class-D” amp instead of an amp clamp around supply voltage to pick a fuse for this 1 of 3 components. If they did it correctly, add all 3, then pick a main fuse next to the battery.
Look, some techs won’t touch an automatic other than fluid & filter, but math used in electrical circuits, be it voltage drop, power solving or simple ohms law is not 100% accurate but real close.
I really enjoy learning an watched twice. I can see there is a slight difference in time on the control side to out put. I don’t teach electronics at this level but I don’t like welding cable pinched in doors going into the trunk with a 300 amp fuse or none at all.
I thought they were perhaps doing drive-by welding on mailboxes or exhaust. This is crazy. Thanks so much as you have many videos to watch that I want to know! Don’t retire because you have more work.
DK, ASE master tech, 78. Retired.

[sparkyskinner]

A tad late to the show but, hey, I don't mind the seat at the back. Fantastic Explanation . I've got a bit to catch up on here with this class D stuff but your explanations are making it much easier to get there. Really enjoying the vids. Thanks Eddie. Great job.

[pedrolourenco]

very cool video! learned something today!

[samanthadeepal]

Superb explanation. Thank you so much! 👍👌🙏❤️

[garydirkse]

Thank you for another great video Eddie. I tried the zoom trick and got lies from my GW Instek 200 MHz Oscilloscope! My fault pushing my luck. My 60 MHz Tek showed dashed lines to let me know that it was guessing. My old Tek 468 guessed about right though it is a 2.5 MHz one shot bandwidth. I was trying to measure fast fall times of monostables and capture the mono pulse width at the same time. Eventually I saw my mistake and triggered on the falling edge with a fast sweep speed. Periodic signals are less subject to operator error.

[misterjorous]

Nice video!!! Looking foward for the next video.
Cheers!!!

[makarov]

Back in the 1970s, the Harris Company built 50KW AM radio transmitters using this technology in their audio path to conserve power and heat. It was very effective. At that time and decade it was called pulse-width modulation. The 25KW power needed to properly modulate the 50KW carrier was generated this way. 90% audio efficiency was achieved. Modern audio class D amps are relatively speaking this efficient.

[kevinkang]

Nice video! I like your way of explaining how class D amplifier works.

[rods]

thanks great video. one of the best on class D amps. I'm sure you could get more DMM's on your bench ha ha (Iam jealous had a set up like that when I was on the bench)
Would have liked some n&d specs when its pumping 100W into 8Ω and to see what zero cross distortion if any?

[batyrlanbopbekoff]

I didn't know that James Hetfield have a good skill in electronic! 👍👍👍

[BjornV]

7:07 That is why some manufacturers of electronic devices use resin to cover the electronics after filling the smoke, so that the smoke stays inside :-)

[orchids]

Another great video, very informative.. Thank you..

[zazio]

With WBG devices as power stage it's almost for sure the switching will be swift and clean. Im wondering the normal Si Mosfet based class-D amps, how they achieve 200kHz+ switching without using huge gate drivers. I mean, the speaker is a inductive load so it must be hard swiched, not that easy to deal with switching losses.