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

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

Jan Cumps — Sun, 02 Dec 2018 18:17:18 GMT

I have this on the desk again. I'm now testing it with the homemade electronic load.

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Output current is 4.86 A. Output is 0.99 V. = 4.81 W

Inputs 36.10 V * 0.15 A = 5.42 W:

I have to add 0.38 W consumption for the controller to the consumption part, making it 5.80 W consumed power vs 4.81 W delivered.

Efficiency is 83%. A little bit lower (possibly reading errors from my side) than the almost 85% of the TI documentation.

[View:/resized-image/__size/610x293/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-d40357e7-093b-4e7f-a8cf-f12d88cec67a/2043.contentimage_5F00_190305.png:610:293]

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This is an interesting setup - with the two output circuits delivering part of the output each.

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The yellow trace is the gate of Q3. The Blue line is drain of Q3, the purple the drain of Q4.

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In reality, things are no so subtle. This is a subst of the design, showing the same FETs and inductors.

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All FETs are GaN devices. On the primary side, the half-bridge sits in a single package. On the secondary side, Each one is actually two GaN FETs in parallel.

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

Jan Cumps — Sun, 21 May 2017 16:09:44 GMT

Measurements for the next blog.

Load 0.05 Ohm

Scope captures:

CH1 PWM high (trigger point)

CH2 Switch node

CH3 output

1st capture output DC, 2nd output AC

no load

input 48V 0.023A 1.14W

output 0.999V

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load

input 48V 0.357 A 17.9W

output 0.982V

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setup photos

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

jw0752 — Sun, 21 May 2017 03:05:04 GMT

Thank You for your continuation of this experiment. It is great to learn about the new technologies.

John

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

Jan Cumps — Sat, 20 May 2017 23:12:57 GMT

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

rachaelp — Mon, 15 May 2017 10:23:37 GMT

An excellent blog again, thank you, and for me this is really interesting, and I need to go back through all your earlier blogs on this again but much like[mention:4966e6ad97f64dac9ea8919abb220e1d:e9ed411860ed4f2ba0265705b8793d05] I too have quite a few ideas in my head for uses of this circuit now. I like the simpler transformer and that smaller inductors can be used, I have a project where currently the transformer and inductors are a significant cost factor and this might allow me to alter the design to use a cheaper transformer and smaller inductors. I need to do some more research!

Best Regards,

Rachael

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

DAB — Sun, 14 May 2017 18:27:47 GMT

When you began this series, I was just so-so on interest, but as you have revealed the capabilities, you now have my mind abuzz with potential uses for the circuit.

I really appreciate your efforts in educating me to this potentially valuable resource.

Hopefully I can resolve my ideas into an implementable project.

DAB