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Old 8th January 2013, 05:21 PM   #11
Baldin is offline Baldin  Denmark
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Think Fredos is on the spot with 6N137. U1 and U3, bust be delivering 5V (or so) from pin 8 ..... still have no idea of what IC it is!

It's not a triple feedback network. The two signals to U6 measures signal over R17 and therefore output current, which when over a certain level will short the input signal.

But there is both a pre- (through R27)and post filter feedback (through R32||C11)... quite nice for 80's design
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Old 8th January 2013, 06:57 PM   #12
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Thanks makes sense to me.
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Old 8th January 2013, 08:55 PM   #13
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U1 and U3 have to be the old MC3842, i fit in the design, and have a build in 5V regulator...
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Old 10th January 2013, 08:27 PM   #14
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Thanks Jesper this one looks like a good choice!

Am I right to choose the AMC3843 instead of AMC3842 because of the "on" threshold of UVLO?

AMC3842 16V on 10V off
AMC3843 8.4V on 7.6V off

Vdrive is about 15V
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Old 22nd January 2013, 04:19 PM   #15
mskeete is offline mskeete  United Kingdom
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Quote:
Originally Posted by Joseph R View Post
And the builder does not live anymore so no chances to kow :-(
He's alive and well. Someone I know spoke to him last week
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Old 22nd January 2013, 05:30 PM   #16
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Wow great! I would love to meet him and discuss about his stuff. Do you know if he still repairs his amps?
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Old 14th June 2013, 12:42 PM   #17
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Joseph R...
Look for this help to you?
You have more PICTURES?
Send for me to help.

Test...
U2 and U4 = HCPL-2611 / 6N137
U1 and U3 = TC4427
Attached Images
File Type: png Look to Help.PNG (73.6 KB, 136 views)

Last edited by lindomar; 14th June 2013 at 01:00 PM.
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Old 17th June 2013, 01:26 AM   #18
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Can anyone tell me quel is the trademark and model of that amp? Thank you.
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Old 5th August 2014, 06:00 AM   #19
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Quote:
Originally Posted by phase_accurate View Post
I'd say this is to prevent/reduce shoot-through.
Regards

Charles
How?
& Also there is no Anti-parallel diode after those two inductors, going towards the rails to snub any VDS avalanche situation arising from overshoot-undershoot at the junction of three inductors.

Last edited by Workhorse; 5th August 2014 at 06:23 AM.
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Old 5th August 2014, 12:27 PM   #20
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I have to admit that it doesn't look too complete in terms of snubbers and stuff.

If you just have a look at the shoot-through situation you can see that you have a series inductance between the high-side and the low side switches. Shoot through situtions usually last for only short time. During this time an inductor should be enough to keep shot-through current within reasonable limits. The devise in question actually works as an autotransfomer at this very moment.

Regards

Charles
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