Super Regulator, collecting the facts

[KlipschKid]

Does anyone know the internal design of the LM723 ? How about the bandwidth etc of the internal error amp ? I'd like to try Jung's super-reg but I'm wondering how to connect a current source into the output of the error amp to bias into classA, and also a diode to control flow into its output. Here is the functional diagram :



Can I use the frequency compensation pin ? The diagram appears to suggest I can but of course I don't know what the actual circuit is.

I'm planning to connect the unregulated input supply directly to pin11, and a regulated supply to pin12. Vref connects to the non-inverting input via a low-pass filter.

I'll start with unity gain with the output connecting to the inverting input via a 10K resistor.

I was wondering if I could also use the zener between pins 9 and 10 as the zener on the output of the error amp ?

Any help is greatly appreciated !

[KlipschKid]

Doh !

[jackinnj]

.SUBCKT LM723 2 3 4 5 6 7 9 10 11 12 13
* CL CS IN- IN+ VREF VCC- VZ OUT VC VCC+ FRCO
*
AZ1 15 12 ZENER1
J1 15 7 7 JMOD
R1 15 16 15K
Q1 16 16 17 QP1
Q2 20 16 19 QP1
Q3 20 21 7 QN1
C1 20 21 5PF
Q4 12 20 22 QN1
Q5 12 22 23 QN1
R2 23 6 100
AZ2 25 6 ZENER1
R3 21 25 30K
R4 25 7 5K
R5 12 17 500
R6 12 19 25K
R7 12 26 1K
Q6 27 16 26 QP1
Q7 23 27 28 QN1
Q8 27 28 29 QN1
R8 29 7 300
R9 28 7 20K
R10 12 30 1K
Q9 13 16 30 QP1
Q10 22 5 33 QN1
Q11 13 4 33 QN1
Q12 33 28 34 QN1
R11 34 7 150
Q13 12 13 36 QN1
Q14 11 36 10 QOUT
AZ3 10 9 ZENER2
Q15 13 2 3 QN1
R12 36 37 15K
I1 0 9 0
I2 0 2 0
I3 0 3 0
.MODEL QN1 NPN (BF=200 BR=2 RB=200 RC=200 RE=2 TF=0.35N IS=1E-14 VAF=125
+ CJE=1.0P VJE=0.7 MJE=0.33 CJC=0.3P
+ VJC=0.55 MJC=0.5 CJS=3.0P VJS=0.52 MJS=0.5 )
.MODEL QP1 PNP (BF=50 BR=4 RB=300 RC=100 RE=10 TF=30N IS=1E-14 VAF=50
+ CJE=0.3P VJE=0.55 MJE=0.5 CJC=1.0P
+ VJC=0.55 MJC=0.5 CJS=3.0P VJS=0.52 MJS=0.5 )
.MODEL QOUT NPN BF=80 RB=10 RC=5 IS=1E-16 VAF=50 CJE=10P CJC=10P
+ TF=3N TR=20N
.MODEL JMOD NJF VTO=-3 RS=1 RD=1 LAMBDA=.02 CGS=5P
.MODEL ZENER1 zener( v_breakdown=6.6 i_breakdown=0.02 r_breakdown=1.5 i_rev=1e-4 i_sat=1e-12)
.MODEL ZENER2 zener( v_breakdown=6.2 i_breakdown=0.02 r_breakdown=1.5 i_rev=1e-4 i_sat=1e-12)
.ENDS

[KlipschKid]

Hi,

I have LT Spice but I don't know how to load code into it - sim noob. I saw a discussion about that code here :

lm723 ripple rejection ratio @100kHz

and it seems it has a very good ripple rejection and low noise, which is what i want - it'll be a pre-regulator feeding a 5V LT1763, a 2.8V LT1761 and a 5V LT1761, drawing 50mA in total (for the analogue supply of an AD1955 DAC).

[KlipschKid]

Well, I entered it as a netlist but it doesn't run and says AZ1 is missing a node ?

[KlipschKid]

I tried using it but I'm having problems with the circuit, so I'm abandoning my efforts. Instead I'll use a jfet cascode to turn on an LM329 + red LED for 8.7V, and feed that via a low pass filter into the base of a BC550C.

[DDB]

Has anyone purchased and built any superreg boards from http://www.at-tunes.co.uk recently? These are the original Andrew Weekes design although I am unsure if he has anything to do with them now. I thought they originally were 2oz copper and now they are 1oz, other than that they are the same board I believe WJ indicated worked well. I want to build some +/- 15V for a low distortion oscillator using the AD825 and LM329 as per his boards so if anyone has built these what did you think of them?

[martin clark]

Just fine, yes they are the original ALWSR design and work exactly as described.

[peranders]

DDB, nothing wrong with 1 oz. for the currents you want to take out. Mr ALW seems to have close down the DIY activities but his friend at-tunes is selling his stuff.

[jackinnj]

ALWSR -- you should probably consider using the depletion MOSFET pre-regulator which WJ shows on his blog -- lower Zout than the Weekes version.