GaN Point of Load converter 48V to 1V 50A - part 1: Design Overview

RE: GaN Point of Load converter 48V to 1V 50A - part 1: Design Overview

Jan Cumps — Sun, 14 May 2017 16:52:52 GMT

Part 2 posted : GaN Point of Load converter 48V to 1V 50A - part 2: Current Doubler

RE: GaN Point of Load converter 48V to 1V 50A - part 1: Design Overview

Jan Cumps — Fri, 12 May 2017 10:36:12 GMT

I've shopped around at the brick+mortar electronics shop in Brussels and bought some power resistors.

4 of each of

0R1 10W
1R 10W

At this moment, the point of load circuit is trained by 2 0R1 in parallel, drawing 20 A out of the circuit.

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Output voltage is 0.983V.

RE: GaN Point of Load converter 48V to 1V 50A - part 1: Design Overview

Jan Cumps — Sat, 11 Feb 2017 12:08:50 GMT

A few test setup photo's and scope captures:

[View:/resized-image/__size/621x661/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-4e62f230-fb24-4b4c-8822-991fc287fb15/6330.contentimage_5F00_190287.png:621:661]

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A capture of the high and low driver signal of the primary side with screen persistence of 5s, one with the trigger on high signal, one with low.

[View:/resized-image/__size/620x372/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-4e62f230-fb24-4b4c-8822-991fc287fb15/4251.contentimage_5F00_190289.png:620:372]

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And a random photo of the setup because I think it's a pretty one.:

[View:/resized-image/__size/620x654/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-4e62f230-fb24-4b4c-8822-991fc287fb15/7416.contentimage_5F00_190291.png:620:654]

RE: GaN Point of Load converter 48V to 1V 50A - part 1: Design Overview

DAB — Fri, 10 Feb 2017 18:07:12 GMT

Very interesting board.

I am curious, do they have a specific load type?

I wonder if it could drive either a laser diode or a inductive load at those current levels.

DAB

RE: GaN Point of Load converter 48V to 1V 50A - part 1: Design Overview

jc2048 — Fri, 10 Feb 2017 13:15:57 GMT

"I hope that someone with sound electromagnetic knowledge chimes in..."

That's me out of it, then. You'll have to ask one of the PWMs if it's clever theory you want.

It's confusing when you first look at it. That's partly because of the way it's drawn - it looks like a switched transformer. If you redraw the input like this, it becomes clearer:

[View:/resized-image/__size/600x450/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-4e62f230-fb24-4b4c-8822-991fc287fb15/contentimage_5F00_190278.jpg:600:450]

the 1:1 transformer is simply using the ripple current in the coil of the input buck converter to induce the voltage in the secondary side which is then synchronously rectified for efficiency. What a neat idea - wish I could think of things like that. Can't quite get my head around the control side for the moment - does the input have to operate at the point between continuous and discontinous operation? Perhaps I should read the datasheet...

Be careful with probing this one.