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.
My Regulator based on Salas Shunt Regulator
Regards 🙂
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Regards 🙂
Yes, just custom layout for PCB. Thank you very much for the schematic. It's sound wonderful.
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
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.
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.
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.
The GND connection I mean is the 'S0' connection. This connection is according to the schematic.
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...
@Studiostevus : What BC547 did you use?
@Salas : Is it possible to see oscillation without oscilloscope?
Regards 🙂
@Salas : Is it possible to see oscillation without oscilloscope?
Regards 🙂
If you move a portable AM radio over an oscillating circuit it can pick it up given its strong and high enough. Not reliable, kinda Mad Max world solution.
Plain BC547's...
I just noticed that on both my negative regs, the bc547's get really hot
I just checked on the scope: the -15V reg (the troubling one) is absolutely not stable. The output voltage moves irregularly down, on the scope visible as the trace pulling several mV's down. It's very irregular, i can't see any particular pattern, it's more like flickering, and goes instantly 😕
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