The simplistic Salas low voltage shunt regulator

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Mosfet has almost no gate current but more capacitance so it needs higher gate stopper to bring the two versions in comparable Bode open loop gain plot for zero point phase margin. Its good it worked for you in a completely different layout also. No worries about the old blocking part, I do worse mistakes all the time. Regards.
 
Funny stuff here... My 4 salas shunts seemed to be working correctly.... However one of them has a problem: the bc547 gets really hot and eventually burns (after several hours)

Specs:
Bib version, but on my own pcb, using irf610 for ccs and irf620 for shunt
Vout=15v
Vin=25v
Ccs=130mA
Iload=50mA tda1541a

Any ideas?

The other 3 regs on the board (5v, -5v, 3.6v) all work fine
 
How's this?
Note that there are positions for some caps which are not used. Also I have connected the collector of the BC547 (depicted on the picture as BC550) to GNDplane. For the rest this is accurate.

Screen shot 2012-07-08 at 5.03.07 PM.png
 
diyAudio Chief Moderator
Joined 2002
Paid Member
Funny stuff here... My 4 salas shunts seemed to be working correctly.... However one of them has a problem: the bc547 gets really hot and eventually burns (after several hours)

Specs:
Bib version, but on my own pcb, using irf610 for ccs and irf620 for shunt
Vout=15v
Vin=25v
Ccs=130mA
Iload=50mA tda1541a

Any ideas?

The other 3 regs on the board (5v, -5v, 3.6v) all work fine

See if the 170 on top of it feeds it too much current. Could that 170 got shorted dead? See if something oscillates in the particular unit if all its semis are healthy.
 
See if the 170 on top of it feeds it too much current. Could that 170 got shorted dead? See if something oscillates in the particular unit if all its semis are healthy.
Do you mean U$22 in my schematic?

I have replaced it yesterday, as I thought it was the reason for the trouble I had. It turned out that the BC547 was the problem. After I replaced it (yesterday), regulation was back, however after listening to the unit for some hours today, again the voltage was drifting upwards as the bc547 got hotter and hotter...
 
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