Super Regulator

- You are not just talking to me. You are talking to members of this forum many of them do not know circuits as these by heart, but would be interested to follow this and/or offer insight. That's the nature of this forum. It's not a one-to-one affair.

- You may have made an error adapting a known circuit to your own use. This does happen, and we should always discuss the actual implementation that gives the problem.
Good point.
My gut feeling is that you have not a full grip of what happens during start-up.
No certainly not. That's the big question.
 
Good morning to all and excuse my English.
I have some problems with the regulator and then I thought about asking here.
can you help me please? .
the questions are many, please be patient.

- I do not understand the following sentence:
"A word about the input voltage from your rectifier / reservoir caps: make sure it is at least 5V above the required output voltage."

- what does the following text mean? :
"And, do not put a high-quality film cap at the output of the regulator! 10 oF (and do not overdo it) at the end of the period.
Do I need to add a 10 μF capacitor between output and load?

- 0.25W resistors are often metallic film?

- between the diode rectifier bridge and inputs J1, J5 must I add a capacitor or are sufficient C2, C6?

- I need two positive and equal tensions for
feed the PCM1794 + 8V + 8V chip (can you do?) and two opposite voltages for the carlsor + 12V-12V buffer for DDDAC1794 and then I did the following calculations using the formulas from the Jan Didden web page.

x output + 12-12 volts:
R5, R12 = (12V - 6.9V = 5.1V) then 5.1V / 0.002mA = 2.55k ohms
D5, D10 = 6.9V LM329
D2, D7 = 6.2V
BZX79B6V2 R0G Taiwan Semiconductor | Mouser Italia
R13, R7 = 6.9V / 0.002mA = 3.45K ohms
V (R14, R6) 12V - 6.9V = 5.1V
R14, R6 = (5.1V / 6.9V) x 3.45K = 2.55K ohms

x output + 8 + 8 volts:
R5, R12 = (8V - 6.9V = 1.1V) then 1.1V / 0.002mA = 550 ohms
D5, D10 = 6.9V LM329
D2, D7 = 3.9V
BZX55C3V9 R0G Taiwan Semiconductor | Mouser Italia
R13, R7 = 6.9V / 0.002mA = 3.45K ohms
V (R14, R6) 8V - 6.9V = 1.1V
R14, R6 = (1,1V / 6,9V) x 3,45K = 550 ohms

I noticed from my calculations that R5, R12, R14, R6 are the same, but in the order table on the web page R14, R6 is twice the size of R5, R12.
Furthermore :
R13, R7 are greater than R14, R6 instead in the order table on the web page are the same.
Where did I go wrong ?

- I can not figure out how to make connections for remote sensing of J2, J6
 
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- I do not understand the following sentence:
"A word about the input voltage from your rectifier / reservoir caps: make sure it is at least 5V above the required output voltage."

I don't know how to make it more clear. You know what the rectifier output means? That is the input to the superreg.

Do I need to add a 10 μF capacitor between output and load?

It is a DC supply. Do you think there will be a DC current from regulator to load if there is a cap between regulator to load? ;-)
The output cap goes from output to ground and is clearly shown on the schematics.

For my superreg, all important issues are addressed in the writeup accessible from the diyaudio store super reg page.

I am sure P-A has a similar writeup.

Jan
 
When it comes to minimum input voltage it is dependent of the LED colour. Red, yellow and green LED will generate 2.0-2.5 V drop out voltage and using a blue or white LED will add up to 2 V. The minimum voltage is with the ripple included so under no circumstances under 2.5 V but for having a marginal 5 V or more is recommended.

A good side effect is that the LED is on when you have a stable output voltage.
 
I've had a couple Super Regulators using the Old Colony boards since 2000. They've been ultra reliable and I used the AD817s on them.
I've been pretty much away from the discussion of this reg since then.
I am wanting to build another one to power the op amp IV stage on my Sabre DAC.
I have a couple questions as I move forward on this.
Back in 2000, there was a mention of a bootstrapped 3 term reg for the input... this idea seems to have died off and rarely mentioned. I could not find a definitive reason why bootstrapping is not being used anymore. Where might I find any information on this?
Would using a preregulator like a normal 317/337 PS ahead of the SuperReg be of any benefit at all anymore? or is it better to just use a clean rectified and smoothed DC source?
Thanks all.
Mike
 
I asked the same question some time ago and, IIRC, and maybe someone can confirm or correct if I've recalled wrong:

Inserting a 317, etc, before the super reg, in some ways, limits the performance of the super reg to that of the pre-reg. But it can, or does, somewhat improve the rejection of power supply ripple.
 
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"Bootstrapping" is sometimes the name given to a cascade of two series voltage regulators, in which the reference voltage for the upstream regulator is derived from the output voltage of the downstream regulator.

I'm not enthusiastic about this connection, because it means the upstream regulator's reference voltage includes some portion of the output noise and ripple. The not-bootstrapped approach, in which the upstream regulator's reference voltage generator is connected to GROUND (rather than the output), must be quieter. So -- no bootstrapping for me.

Other circuit designers have other opinions, of course.
 
I asked the same question some time ago and, IIRC, and maybe someone can confirm or correct if I've recalled wrong:

Inserting a 317, etc, before the super reg, in some ways, limits the performance of the super reg to that of the pre-reg. But it can, or does, somewhat improve the rejection of power supply ripple.

Not going to look for the measurements, but the LM317 wrap around increases the output impedance slightly, improves PSRR and has minimal effect upon noise.
 
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MCP6022

Or search the Analog Devices website for SMD-only, <4V supply , silicon germanium rail to rail opamps. Be sure to get one that's ultra stable (phase margin > 60 degrees) at unity gain.

I think that's a dual.

I would try the AD8031; I'm using that in high voltage regulators.
It's also available in DIP08, some prefer that.

Jan
 
I think that's a dual.

I would try the AD8031; I'm using that in high voltage regulators.
It's also available in DIP08, some prefer that.

Jan

Jan, thanks for the suggestion. I like that op amp. The previously suggested one seemed a little low in bandwidth as I am aiming for a very fast PS for a DAC AVCC.

This evening I was testing an AD817 vs. an LME49710 in the DAC IV circuit and I was surprised to hear the difference. I was not expecting it.

Now with respect to improved PSRR vs. output impedance, when would one choose one aspect over the other? Can you suggest certain circumstances that would allow me to prefer to implement one over the other?

Also, any thoughts on using an LTC6655 as the reference voltage? This should improve noise over the LM329? https://www.analog.com/media/en/technical-documentation/data-sheets/6655ff.pdf
 
...I am aiming for a very fast PS for a DAC AVCC...

LTC6252

If your building from scratch... otherwise you will need an adaptor - different pin out.
I don't know if it will work correctly in the super reg, I haven't tried it but it looks like it will fit the bill: I'm ordering some to try.

Gain Bandwidth Product: 720MHz
–3dB Frequency (AV = 1): 400MHz
Low Quiescent Current: 3.5mA Max
High Slew Rate: 280V/μs
Input Common Mode Range Includes Both Rails
Output Swings Rail-to-Rail
Low Broadband Voltage Noise: 2.75nV/√Hz
Power-Down Mode: 42μA
Fast Output Recovery
Supply Voltage Range: 2.5V to 5.25V
Input Offset Voltage: 350μV Max
Large Output Current: 90mA
CMRR: 105dB
Open Loop Gain: 60V/mV

...Also, any thoughts on using an LTC6655 as the reference voltage? This should improve noise over the LM329?...

Use the 1.25V version, set the gain to x2.64 for 3.3V out.
 

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LTC6252

If your building from scratch... otherwise you will need an adaptor - different pin out.
I don't know if it will work correctly in the super reg, I haven't tried it but it looks like it will fit the bill: I'm ordering some to try.

Gain Bandwidth Product: 720MHz
–3dB Frequency (AV = 1): 400MHz
Low Quiescent Current: 3.5mA Max
High Slew Rate: 280V/μs
Input Common Mode Range Includes Both Rails
Output Swings Rail-to-Rail
Low Broadband Voltage Noise: 2.75nV/√Hz
Power-Down Mode: 42μA
Fast Output Recovery
Supply Voltage Range: 2.5V to 5.25V
Input Offset Voltage: 350μV Max
Large Output Current: 90mA
CMRR: 105dB
Open Loop Gain: 60V/mV



Use the 1.25V version, set the gain to x2.64 for 3.3V out.

Well I have some LM385 - 1.2 (20yrs old) and I also have a LTC6655-1.25 already so that kind of seals the deal for what I will try there. I also like the ease of using a normal DIP verison of the AD8031. But there are options.
 
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