Salas SSLV1.3 UltraBiB shunt regulator

[juliobozek]

Yes, of course I will insulate the mosfet from heatsink.

Thanks for the help!

 

[juliobozek]

New double positive regulator with custom pcb is alive.
It will be used for DAC, one for digital and one for analog power supply.

This is 4 layer pcb with 2 internal ground planes.

Anyways, the supply is extraordinary thanks to the Salas!

 

[Salas]

Why one side has three TH resistors underneath and the other does not?

 

[NikNet]

Good day! I wanted to know if capacitor C3 is required? If the legs of the microcircuit already have capacitors?

 

[juliobozek]

Why one side has three TH resistors underneath and the other does not?

This is a CCS resistor (3 in series), and I didn't have the vaule I needed. It will be replaced soon with single one.

It is hard to see but i have PANASONIC 100nf PPS film capacitors between Q2 base and GND (parallel to C2), one is between Q3 base and GND, and there is a 0402 3.3nf C0G capacitor between two leds and GND.
The LEDs are HLMP-6000.

I got interesting results with this configuration. Somehow highs are more alive.
I don't have any preregulation on my DAC - it is supplied directly with this regulator.

 

[juliobozek]

And yes, my DAC has only 100nf PPS decoupling capacitors. There are no big electrolytic caps which could influence the regulator

 

[Salas]

Good day! I wanted to know if capacitor C3 is required? If the legs of the microcircuit already have capacitors?

Required

 

[Salas]

It is hard to see but i have PANASONIC 100nf PPS film capacitors between Q2 base and GND (parallel to C2), one is between Q3 base and GND, and there is a 0402 3.3nf C0G capacitor between two leds and GND.
The LEDs are HLMP-6000.

I got interesting results with this configuration. Somehow highs are more alive.
I don't have any preregulation on my DAC - it is supplied directly with this regulator.

Here's the situation, generally more phase shift before zero gain.

 

[juliobozek]

Thank you for the graphs Salas. So generally those extra capacitors shouldn't hurt the regulator in any situation?

 

[juliobozek]

Is it OK to decrease C1 value to have less effective voltage across M1 for less heat dissipation?

For example I now have 320mA CCS setting, 12VAC 35VA transformer (outputting 13.8VAC), C1 is 4700uF and M1-Vds = 9V
I planned to make C1 2200uf or even lower.

 

[Salas]

Thank you for the graphs Salas. So generally those extra capacitors shouldn't hurt the regulator in any situation?

Stability wise they don't hurt it, it still has -120deg phase at zero gain.

 

[Salas]

Is it OK to decrease C1 value to have less effective voltage across M1 for less heat dissipation?

For example I now have 320mA CCS setting, 12VAC 35VA transformer (outputting 13.8VAC), C1 is 4700uF and M1-Vds = 9V
I planned to make C1 2200uf or even lower.

Decreasing C1 increases ripple voltage. Which is AC. Thus you get less DC. I don't think its wise to exchange little heat benefit with more ripple. Ripple is detrimental.

 

[jimk04]

Hi Nic. Not sure if I missed it but is there an alternative for the application of the FQPs in the Ubib now that they are getting hard to find?
Obviously assuming we need CC >1A.!

 

[Salas]

Hi,

IRF9620 (positive section M1) IRF620 (negative section M1) for up to about 2A continuous, then for more current the IRF9630/630. The stronger the type the slower (more parasitic pF in the semiconductor die).

 

[juliobozek]

Stability wise they don't hurt it, it still has -120deg phase at zero gain.

Thank you!

 

[juliobozek]

Decreasing C1 increases ripple voltage. Which is AC. Thus you get less DC. I don't think its wise to exchange little heat benefit with more ripple. Ripple is detrimental.

Thanks! So I will find 10VAC transformer instead

 

[Salas]

You could alternatively add a few Ω power resistor between bridge and C1 making RC filter and eating some DC voltage. It will dissipate some power itself of course. Not a good looking botch on a finished pcb design also.

 

[Properdouble]

Hello . I have a question - how low i can go with voltage ?
I want to power I2S over usb kind off like xmos usb to spdif . I need 4 -5.3 v 400ma for usb side and 4.5 -5.3 for oscillator reclock 100ma. I have a transformer 20Va with 10v ac output. Obviously I would built 2 separate ultra bib . Can I power them from the same transformer ?
They would not be connected at any point on the I2S board .
I recieved with my kit PF5103 with label below 7.5 ma . Do I need one per ultra bib ? Where does it need to be installed as on pcb there is 3 of them ?
Thank you .

 

[juliobozek]

You could alternatively add a few Ω power resistor between bridge and C1 making RC filter and eating some DC voltage. It will dissipate some power itself of course. Not a good looking botch on a finished pcb design also.

I thought about that. I might combine a bit bigger resistor (so it fits the PCB) and a lower voltage transformer. I need to buy new transformers anyway.

Again, thanks for the help!

 

[Properdouble]

Hello . Ok . I found info i needed so I installed J3 and silly me I swaped by mistake M1 with M2 soon as i saw no leds and smoke I immediatly turned power off. Pulled M1 and M2 cause needs to change their location anyway. Checked both and both ok on tester . Quick test with multimeter show no components failed . Is that possible . What could fail most likely ? Thank you . I could cut my hand off that i checked everything 10 times . Oh well.