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

[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.

[Ioannis]

This is not a heatsink. It is a sample of heatsink!

Ioannis

[Demon]

Tested the TPS56637 against my prototyping board. It's operating beyond expectations for heat. The only thing I could improve is the ripples in the lines. I think max peak-to-peak was 22mV during preliminary tests, and the TI's Webench power designer tool said 11.73mV.

It took a lot of trial and error playing with capacitors,, but I've found a happy medium that runs under 11mV except for the LED strip.




As I say in the video, I'm going to reorganize the board so the TPS56637 is in the middle, and all breadboard rails get individual VDD/VSS lines. the only drawback is that I'm going to lose that centralized row of input capacitors, but I've already got an idea to solve this as I'm typing.

And I'm not sure what I'm going to do with that bank of capacitors on the breadboard. There's about 18 of each (I just emptied my box compartment). I did notice that it costs some mV to feed all those caps.

I'd really like to keep a MOSFET for the LED strip cause right now I'm limiting how much current it consumes (I think it's 180mA). But if the TPS can supply so much more efficiently, I'm thinking of letting the PWM rate go up a bit higher. It'll all depend on how the TPS behaves with 3 LED strips connected.

[Ioannis]

I am glad you got the results you hoped for.

With all those ground loops and the probe cable also, I'd expect much more noise of that!

Usually to measure noise on a regulators rail, you would ditch the cable with the crocodile clip and use a coil spring to earth the probe as close as possible near the tip.

Adding so much capacitance, from a certain point on, is not worth it as much as have good grounds.

Congrats,
Ioannis