The simplistic Salas low voltage shunt regulator

[vgeorge]

This is what I used : http://www.diyaudio.com/forums/powe...-voltage-shunt-regulator-314.html#post3791710 for my Subbu DAC.

You can use use what value capacitor you like, in a CRC arrangement before the regulator and calculate R by using Ohm' law.

 

[kinku]

George ,Can you please explain a bit more. What part of your circuit is the CRC?

 

[vgeorge]

After the rectifier, before the regulator.

 

[kinku]

Components on the way from digikey and ebay. How do you guys check the circuit for noise and stuff?

 

[Salas]

With oscilloscope. The Reflektor is not too easily reactive though.

 

[kinku]

Does anyone has a Reflektor with a 1amp continuous ,2amp peak rating?

 

[Salas]

Cant do that with the 9610 but can try with a 9640 and really good sinking. Big heat penalty if set at 2A peak and little is used up in average.

 

[kinku]

Cant do that with the 9610 but can try with a 9640 and really good sinking. Big heat penalty if set at 2A peak and little is used up in average.

Is there any modifications needed in circuit (George's design) if 9640 is used?

 

[Salas]

I don't think so, although danger for instability may occur with any change in such wide bandwidth systems. The current should be set far higher with a much smaller control resistor of course. 9640 has much more parasitic capacitance (a price to pay with stronger silicon die) vs the 9610. So that's a change. It will also be a less effective CCS as the frequency goes higher. Mainly beyond the audio band.

 

[cwtim01]

Reflektor 10V

Hi,

I would like to build a Reflektor @10V and 300mA. May I know if the attached circuit is OK. Basically it's a redrawn of the original circuit at post #4287, with the following changes:

• Certain R and C values are updated, based on schematics of some later posts;
• J1 is a BF861A (Idss 3.2mA - 5.5mA) as I have some stocks, and I use R4 of 50ohm to give around 2.5mA of Id
• M2 is IRLZ24, leftovers from another project. Is this MOSFET ok?

Thanks and regards.

 

[Salas]

Your semis look compatible enough with the line of the other builds, it should work. You could use an all red Leds low noise ref though. Don't know about that 5V one and self noise. A smaller 100-200R trimmer could do only fine tuning of Vo.

 

[cwtim01]

Thanks Salas for your quick reply, to be safe I'll change to use normal red LEDs then (is the one attached OK? it sells at 5 dollar per 100 pieces at a local store so I'll probably buy it).

 

[Salas]

It looks OK.

 

[cwtim01]

Thanks, and I have another question, is it possible to use 2 positive Reflektor to create a dual rail supply, by having separate transformer secondaries and rectifier bridges, like in the attached schematic.

I want to use this to power a Kuartlotron buffer by Keantoken.

Thanks and regards.

 

[Salas]

When stacking same polarities to dual its like when stacking batteries. Arrange the Kelvin wiring like in the attached drawing. You may use more LEDS and smaller trimmer value to have the best part of the 10Vout made up by active parts.

 

[kinku]

Ok I made the Reflektor from parts on a vero board but for sure did not do something right. No voltage out put. How to trouble shoot?I am feeding with 20VDC and using Georges circuit with resistors R2,R3,R6 150Ohm and R1 0.82 Ohm. I am getting 20V between IRF9610's drain and Ground.

 

[Salas]

Trace it out carefully against the original circuit. BTW, there is an open connection between the two Leds in that drawing from George, that is some print glitch, it should be connected.
If all is well with the wiring, then you will look for dead semis that do not show VBE or VGS voltages or dead LEDs. Or bad orientations, check pinouts.

 

[kinku]

2n4403 or 2SK117 sensitive to heat? I think I really made them hot while soldering?
I can not find any voltage between Q5 VBE,I am using a 0.82Ohm R1.Is it too low?

 

[Salas]

0.82 is for 700mA+ setting if that was your target. 0.6V/R1=ICCS. Exchange suspect semis only after you know all physical connections and orientations are loyal to the drawing.

 

[kinku]

I changed the 2N4403 and check the voltage between BE again no reading ,between E and ground 20VDC. where could be the problem?