Introducing the PowerReg

[BobMaximus]

The jfet can limit the output transistor curent, with the TeddyReg it acts as overload protection (you can short-circuit the output and nothing happens, I tried it!).

The TeddyReg is protected by the current limiting in the LM317 anyway, which is in series with the VBE.

The crowbar protection in the 135 PSU suffers in that it begins to limit the output current before the cut-off point is reached. I guess a similar scheme using a relay to short the gate of the 2SK117 to ground would work though.

 

[maxlorenz]

Hi Teddy,

I am projecting some PowerRegs for 40-42VDC out (since the L317 adjust is floating, it should work OK, or that is what I read) for some power amps that I will build this year, since I found some mil-spec solid Tantalum which work until 50VDC, to be used as C4.
For those PowerRegs, I "designed" a PCB which has convenient holes for a jumper from output of the pre-regulator to the Drain of T1: the case is that a canned inductor of 10-33mH also fits there so I soldered one to see what happens. I have not tried it yet...

Have you tried inductors between the pre-reg and the gyrator???

The DC resistance of the inductors is between 7 and 20R (or my multimeter is faulty )
(This idea is also to be tried on my TeddyRegs).

Thanks,
M

 

[martin clark]

Have you tried inductors between the pre-reg and the gyrator??

They'll add virtually nothing; even quite large inductors (10-100s mH) have a tiny impedance compared with the brute-force filtering in Teddy's design; and inductors large enough to add significant impedance will also be limited at HF by the interwinding capacitance starting to bypass what they offer.

Don't let me stop you, it's just an observation

 

[maxlorenz]

OK, Martin. Thanks for the quick reply. I will do the test anyway just to know how it sounds.