Voltage regulation circuit 12V to 5V in 5A range

[Ioannis]

Ten dollars is quite enough. I'd select that 1oz too.

Maybe and more caps too.

Ioannis

[Demon]

I ordered 2 models:

- 4 layers, all 1 oz, 5 for $147 including shipping and duties, $29.40 each
- 2 layers, all 1 oz, 5 for $108 including shipping and duties, $21.60 each

I was able to stay on Economic price by avoiding 2oz layers, and remained at recommended area size by TI.

Output caps, 47uF (recommended), 10uF and 1uF.

I was tempted to add 0.1uF and 0.001uF but I thought I might be exaggerating. I can still add them in the final version if you guys think I should; I have room and it's not like they cost anything.

At least I'll have something to see how it ripples using PWM from transistors and mosfets.

I can also push it for heat test by PWMing a whole roll of LED strip.

[Demon]

I can get the price down a bit more by using another inductor:

Current: XAL1010-332MED by Coilcraft, $4.4191 x 5 = $22.10

Alternative: SRP1265A-3R3M by Bourns, $1.5387 x 5 = $7.70

That's a difference of $14.40 ($2.88/unit)


I didn't use the Bourns cause I'd have to order a minimum of 10 from Mouser, and that takes 8-15 lead days, and I wanted my PCB for testing yesterday.

There was 73 inductors in stock from Coilcraft, but that's already down to 38 (I only used 10 in my 2 orders).


Ioannis, have you had any experience ordering from Element or Onlinecomponents?

[Demon]

Once I get my order and done some testing, I'll be in a better position to know what configuration of layers I'm going to need.

I'm always getting emails from PCB assembly suppliers from alibaba, so I'll to make a RFQ for that "winning" configuration.

Just to see if I can get anything better than JLCPCB.

That'll also give me a chance to find a good competitor for my PCBs in the future. But I gotta admit, JLCPCB's online system is pretty slick once you get used to it.

[Ioannis]

Ioannis, have you had any experience ordering from Element or Onlinecomponents?

No. My country adds a lot of import taxes so I select suppliers within European Union or Mouser that ships tax free.

May main suppliers are Mouser, TME, SOSelectronics and local resellers for larger quantities.

Regarding the inductors, I think either Coilcraft or Burns (or other reputable brands) will make no difference, as long as you select one that has the specs.

At testing time you will see if adding more caps on output of the power supply makes any significant difference. Can't tell right now.

For mass production of assembled pcb JLCPCB may be more expensive. I usually do this for no more than 20-30 pcs, depending on the component count too. Greater production is cheaper for me if I do it locally and just order only the pcb's from JLCPCB.

Ioannis

[Demon]

Assembled, checked each header and basic test on v1; 2 layer, 1-1oz.




Now I need to finish my load tester using this puppy.




The plan is to PWM the power resistor while monitoring current, and using E02 thermal camera to watch heat spots on PCB.

Still undecided if using N or P channel logic-level MOSFET. I have yet to find a good tutorial to determine the base resistor.

[Demon]

Tested on prototype board; 430mA.




Top side, TPS56637 step-down IC is the hottest at 25C, followed by inductor and switch bracket. I just touched power jack at far left, so that's not actual temp.




Bottom side, center is at 23C, the max spots are my finger (can see through top left mounting hole too) and LED strip in background.




That's insane compared to 7805 or LM1084. Humungous difference in efficiency and heat (never expected it to be so much difference).

I can touch this with my fingers.

[Demon]

The LM1084 was maxxing out near 124C, and that was only at 300mA with heatsinks on front and back.




I'm both flabber and gasted.