Help me with my PSU PCB

[Alcaid]

Is the grounding correct on this power supply, or do I need a star ground?

It will be used as a power supply for an active filter in an active subwoofer, and I wonder if it will do the job, or do I need something more complex? It will be used to power two opa2134's.

C1,C2=4700uF elec.
C3,C4,C5,C6=100nF Polypropylene
C7,C8=100uF elec.
R1,R2=220R
R3,R4=2k94

[richwalters]

Hi there........youre doing fine.......a wise bet would be to really beef up the ground tracking especially around the 4700uF filter caps where the commons join. This is where peak currents flow. Common wisdom dictates all ground related layouts be physically made massive and IC bypass caps be physically close to devices.
Remember IC's are also amps, and will oscillate with poor layouts.
The o/p track layout be also thick to take advantage of the low Z impedance. The earthy junctions of R2/4; C7/9;C3/5 should be as short as possible to take advantage of the good PSRR. (power supply ripple rejection)

rich

[Alcaid]

Better like this?

[Alcaid]

...or maybe like this?

[Alcaid]

Should all the traces be of same width? Then it would look something like this...

[tool49]

I might be wrong but this is how I would do it if I had to. I know that two opa2132 will probably require less than 80mA total, but still, fatter traces are easier to make at home and will give you enough headroom even if the transfer/etching process goes wrong.

Sébastien

[Frank Berry]

Sébastien has it.
The bigger the traces, the better IMHO.

[richwalters]

BUILD IT

RICH

[tcpip]

I was trying to "design" a PSU, by putting together two circuits from Randy Slone's Audiophile Projects book. Here's the schematic. It uses LM317/337 for regulation, and uses a high-gain transistor at the ADJ pin of each for making the regulation more sensitive. My schematic keeps only the transformer outside the PCB, and mounts all other parts on the PCB. I guess the circuit will be good for upto about 1A in each leg? That should see me through quite a large set of active xo and preamp and what have you.

Any comments? I'm new, so please point out mistakes.

Tarun

[tcpip]

And I designed the PCB for this thing, in Eagle. Will the layout work? Any tips on PCB design?

I kept two ground terminals on the input side, to allow both leads from a toroidal transformer to come in; normal E+I transformers seem to have just one lead for the centre tap. I also kept three-of-each terminals on the output side, so that up to three different PCBs could easily draw power from this board, without having to do messy wire splicing. In the local market, I get screw-tightened terminal blocks with legs spaced 0.2" apart. I intend to use those for the input and output connections. I've used vertical multi-turn pots for the voltage adjustments... don't know if that's overkill. There's one short jumper, carrying one of the supply rails, near IC1 at the bottom. Couldn't avoid it easily. Though the PCB therefore looks double-sided, I've decided to use a piece of wire for that lead, and make it single-sided.

Comments please. I can't go ahead and make it till I hear from you guys. Don't know what goofups I've made.

Tarun