HI,
My jung super regulator output when turned on:
First 1.6V and then raises to 5.0V after 1-2sec
I need for my Squeezebox 3 (used with coax output only)that the PSU start with 5V on the output
Is it possible if I remove the Pre regulator that the super reg starts with
5V instead of first 1.6V on the output?
Will I loose any performance?
Kim
My jung super regulator output when turned on:
First 1.6V and then raises to 5.0V after 1-2sec
I need for my Squeezebox 3 (used with coax output only)that the PSU start with 5V on the output
Is it possible if I remove the Pre regulator that the super reg starts with
5V instead of first 1.6V on the output?
Will I loose any performance?
Kim
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It allways starts at zero volts 🙂 , the problem is how fast does it raise.
You could try with C2 and C4 (100µ) much smaller (0µ1).
Mona
You could try with C2 and C4 (100µ) much smaller (0µ1).
Mona
Thanks:
I don´t think that will give the big difference - maybe some stability problems🙂
The current use is about 300mA
Would be good to know which schematic are we talking about.
Stability problem doesn't cause slow turn on.
As Ketje mentioned, most probably the capacitor is charged with little current, so it turns on slow.
Stability problem doesn't cause slow turn on.
As Ketje mentioned, most probably the capacitor is charged with little current, so it turns on slow.
Looked at it closer.What did you change to get 5V out of it ?
Normaly the bottem is 7volts. Lower gets the op-amp in trouble, it's power comes from the regulator output and the inputs at almost 7V.
Mona
Normaly the bottem is 7volts. Lower gets the op-amp in trouble, it's power comes from the regulator output and the inputs at almost 7V.
Mona
How much current are you trying to pull from the SR?
Squeezeboxes draw quite a lot of current and as it is, the Jung SR is set-up for 300-500mA. Beyond that - the output transistor can cope fine, but you need to increase the bias of the current source a little to ensure the output transistor is driven hard enough. Without that the voltage will not sustain high loads, or heavy start-up load transients.
Alternatively I wonder if your pre-reg is going into current limiting, hence the slow start.
Note the Jung SR itself does not have a start-up problem - indeed, the CCS bias makes it turn-on hard when you apply power, to make the error amp startup-up fast and pull-down the output. Leave the onboard caps at the value recommended.
Squeezeboxes draw quite a lot of current and as it is, the Jung SR is set-up for 300-500mA. Beyond that - the output transistor can cope fine, but you need to increase the bias of the current source a little to ensure the output transistor is driven hard enough. Without that the voltage will not sustain high loads, or heavy start-up load transients.
Alternatively I wonder if your pre-reg is going into current limiting, hence the slow start.
Note the Jung SR itself does not have a start-up problem - indeed, the CCS bias makes it turn-on hard when you apply power, to make the error amp startup-up fast and pull-down the output. Leave the onboard caps at the value recommended.
That sounds like my situation.. I have split the supplies in the SB3 so I supply the display with the default switch mode with current use around 0.5A and the digital part with a jung regulator (sjostrom PCB) 5V/ 0.3A
You can read about the split on the dungeon hifi page🙂
I will measure some more and get back soon.
Thanks again
I have tested with 10 ohm connected to PSU out =500mA
It seems to be the pre reg is a bit slow in start up, first 5V and then raise to 7.5v from that to input of the D44h11.
Any advices here to improve?
It seems to be the pre reg is a bit slow in start up, first 5V and then raise to 7.5v from that to input of the D44h11.
Any advices here to improve?
I have also read that low noise is important for digital circuits DACS /clocks
maybe more important than a high ripple rejection?
Have someone made a measurement on a super regulator without and pre regulator?
maybe more important than a high ripple rejection?
Have someone made a measurement on a super regulator without and pre regulator?
Well, yes, though not the iteration you have, which is actually an aftermarket interpretation of the Jung SR topology.
It would be worth you trying yours bypassing the pre-reg, to see if the issue you have remains; i.e. - whether the pre-reg is the cause; or if the pre-reg's output is rising slowly because the SR part cannot cope with the load start-up transient. Or you could ask your supplier once you've identified the problem load case...
It would be worth you trying yours bypassing the pre-reg, to see if the issue you have remains; i.e. - whether the pre-reg is the cause; or if the pre-reg's output is rising slowly because the SR part cannot cope with the load start-up transient. Or you could ask your supplier once you've identified the problem load case...
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